Holographic Ricci Dark Energy Model
NASA Astrophysics Data System (ADS)
Saadat, Hassan
2012-03-01
In this paper, we consider holographic Ricci dark energy model, and by using general relativity equations obtain time-dependent density of the Universe. We show that the resulting density in independent of space curvature.
Holographic dark energy model from Ricci scalar curvature
Gao Changjun; Wu Fengquan; Chen Xuelei; Shen Yougen
2009-02-15
Motivated by the holographic principle, it has been suggested that the dark energy density may be inversely proportional to the area of the event horizon of the Universe. However, such a model would have a causality problem. In this paper, we propose to replace the future event horizon area with the inverse of the Ricci scalar curvature. We show that this model does not only avoid the causality problem and is phenomenologically viable, but also naturally solves the coincidence problem of dark energy. Our analysis of the evolution of density perturbations show that the matter power spectra and cosmic microwave background temperature anisotropy is only slightly affected by such modification.
Quantisation of the holographic Ricci dark energy model
Albarran, Imanol; Bouhmadi-López, Mariam E-mail: mbl@ubi.pt
2015-08-01
While general relativity is an extremely robust theory to describe the gravitational interaction in our Universe, it is expected to fail close to singularities like the cosmological ones. On the other hand, it is well known that some dark energy models might induce future singularities; this can be the case for example within the setup of the Holographic Ricci Dark Energy model (HRDE). On this work, we perform a cosmological quantisation of the HRDE model and obtain under which conditions a cosmic doomsday can be avoided within the quantum realm. We show as well that this quantum model not only avoid future singularities but also the past Big Bang.
Holographic Ricci Dark Energy Model with Non-constant c 2 Term
NASA Astrophysics Data System (ADS)
Saadat, Hassan
2013-03-01
In this paper, we study holographic Ricci dark energy model with non-constant c 2 term in dark energy density formula. We consider FRW metric in flat space-time and calculate density. Also we find scale factor and Hubble expansion parameter.
Zhang Xin
2009-05-15
In this work, we consider the cosmological constraints on the holographic Ricci dark energy proposed by Gao et al.[Phys. Rev. D 79, 043511 (2009)], by using the observational data currently available. The main characteristic of holographic Ricci dark energy is governed by a positive numerical parameter {alpha} in the model. When {alpha}<1/2, the holographic Ricci dark energy will exhibit a quintomlike behavior; i.e., its equation of state will evolve across the cosmological-constant boundary w=-1. The parameter {alpha} can be determined only by observations. Thus, in order to characterize the evolving feature of dark energy and to predict the fate of the Universe, it is of extraordinary importance to constrain the parameter {alpha} by using the observational data. In this paper, we derive constraints on the holographic Ricci dark energy model from the latest observational data including the Union sample of 307 type Ia supernovae, the shift parameter of the cosmic microwave background given by the five-year Wilkinson Microwave Anisotropy Probe observations, and the baryon acoustic oscillation measurement from the Sloan Digital Sky Survey. The joint analysis gives the best-fit results (with 1{sigma} uncertainty): {alpha}=0.359{sub -0.025}{sup +0.024} and {omega}{sub m0}=0.318{sub -0.024}{sup +0.026}. That is to say, according to the observations, the holographic Ricci dark energy takes on the quintom feature. Finally, in light of the results of the cosmological constraints, we discuss the issue of the scalar-field dark energy reconstruction, based on the scenario of the holographic Ricci vacuum energy.
NASA Astrophysics Data System (ADS)
Forte, Mónica
2016-12-01
We make a scalar representation of interactive models with cold dark matter and modified holographic Ricci dark energy through unified models driven by scalar fields with non-canonical kinetic term. These models are applications of the formalism of exotic k-essences generated by the global description of cosmological models with two interactive fluids in the dark sector and in these cases they correspond to the usual k-essences. The formalism is applied to the cases of constant potential in Friedmann-Robertson-Walker geometries.
Viscous extended holographic Ricci dark energy in the framework of standard Eckart theory
NASA Astrophysics Data System (ADS)
Chattopadhyay, Surajit
2016-11-01
In this paper, we report a study on the viscous extended holographic Ricci dark energy (EHRDE) model under the assumption of existence of bulk viscosity in the linear barotropic fluid and the EHRDE in the framework of standard Eckart theory of relativistic irreversible thermodynamics and it has been observed that the non-equilibrium bulk viscous pressure is significantly smaller than the local equilibrium pressure. We have studied the equation of state (EoS) parameter and observed that the EoS behaves like “quintom” and is consistent with the constraints set by observational data sets from SNLS3, BAO and Planck + WMAP9 + WiggleZ measurements in [S. Kumar and L. Xu, Phys. Lett. B 737, 244 (2014)]. Analysis of statefinder parameters has shown the possibility of attainment of Lambda cold dark matter (ΛCDM) phase under current model and at the same time it has been pointed out that the redshift z = 0, i.e. the current universe, the statefinder pair is different from that of ΛCDM and the ΛCDM can be attained in a later stage of the universe. An analysis of stability has shown that although the viscous EHRDE along with viscous barotropic is classically unstable in the present epoch, it can lead to a stable universe in very late stage. Considering an universe enveloped by event horizon, we have observed validity of generalized second law (GSL) of thermodynamics.
Instability in interacting dark sector: an appropriate holographic Ricci dark energy model
NASA Astrophysics Data System (ADS)
Herrera, Ramón; Hipólito-Ricaldi, W. S.; Videla, Nelson
2016-08-01
In this paper we investigate the consequences of phantom crossing considering the perturbative dynamics in models with interaction in their dark sector. By mean of a general study of gauge-invariant variables in comoving gauge, we relate the sources of instabilities in the structure formation process with the phantom crossing. In order to illustrate these relations and its consequences in more detail, we consider a specific case of an holographic dark energy interacting with dark matter. We find that in spite of the model is in excellent agreement with observational data at background level, however it is plagued of instabilities in its perturbative dynamics. We reconstruct the model in order to avoid these undesirable instabilities, and we show that this implies a modification of the concordance model at background. Also we find drastic changes on the parameters space in our model when instabilities are avoided.
Bianchi type-I and -III modified holographic Ricci Dark energy models in Saez-Ballester theory
NASA Astrophysics Data System (ADS)
Rao, V. U. M.; Divya Prasanthi, U. Y.
2017-02-01
In this work, we study the spatially homogeneous and anisotropic Bianchi type-III (B-III) and locally rotationally symmetric (LRS) Binachi type-I (B-I) models filled with matter and dark energy in the framework of the Saez-Ballester (1986) scalar-tensor theory of gravitation. Here, we consider the modified holographic Ricci dark energy as the viable candidate to dark energy. To obtain a deterministic solution we consider the time-varying deceleration parameter, which leads to the average scale factor a(t)=[sinh(α t)]^{1/k}. This average scale factor describes a model which generates a smooth transition of the universe from the early decelerating phase to the recent accelerating phase. The physical and kinematical aspects of the models are discussed through figures and also found to be in good agreement with recent astrophysical observations under suitable conditions.
Non-adiabatic perturbations in Ricci dark energy model
Karwan, Khamphee; Thitapura, Thiti E-mail: nanodsci2523@hotmail.com
2012-01-01
We show that the non-adiabatic perturbations between Ricci dark energy and matter can grow both on superhorizon and subhorizon scales, and these non-adiabatic perturbations on subhorizon scales can lead to instability in this dark energy model. The rapidly growing non-adiabatic modes on subhorizon scales always occur when the equation of state parameter of dark energy starts to drop towards -1 near the end of matter era, except that the parameter α of Ricci dark energy equals to 1/2. In the case where α = 1/2, the rapidly growing non-adiabatic modes disappear when the perturbations in dark energy and matter are adiabatic initially. However, an adiabaticity between dark energy and matter perturbations at early time implies a non-adiabaticity between matter and radiation, this can influence the ordinary Sachs-Wolfe (OSW) effect. Since the amount of Ricci dark energy is not small during matter domination, the integrated Sachs-Wolfe (ISW) effect is greatly modified by density perturbations of dark energy, leading to a wrong shape of CMB power spectrum. The instability in Ricci dark energy is difficult to be alleviated if the effects of coupling between baryon and photon on dark energy perturbations are included.
Holographic Dark Energy Density
NASA Astrophysics Data System (ADS)
Saadat, Hassan
2011-06-01
In this article we consider the cosmological model based on the holographic dark energy. We study dark energy density in Universe with arbitrary spatially curvature described by the Friedmann-Robertson-Walker metric. We use Chevallier-Polarski-Linder parametrization to specify dark energy density.
Redshift drift constraints on holographic dark energy
NASA Astrophysics Data System (ADS)
He, Dong-Ze; Zhang, Jing-Fei; Zhang, Xin
2017-03-01
The Sandage-Loeb (SL) test is a promising method for probing dark energy because it measures the redshift drift in the spectra of Lyman- α forest of distant quasars, covering the "redshift desert" of 2 ≲ z ≲ 5, which is not covered by existing cosmological observations. Therefore, it could provide an important supplement to current cosmological observations. In this paper, we explore the impact of SL test on the precision of cosmological constraints for two typical holographic dark energy models, i.e., the original holographic dark energy (HDE) model and the Ricci holographic dark energy (RDE) model. To avoid data inconsistency, we use the best-fit models based on current combined observational data as the fiducial models to simulate 30 mock SL test data. The results show that SL test can effectively break the existing strong degeneracy between the present-day matter density Ωm0 and the Hubble constant H 0 in other cosmological observations. For the considered two typical dark energy models, not only can a 30-year observation of SL test improve the constraint precision of Ωm0 and h dramatically, but can also enhance the constraint precision of the model parameters c and α significantly.
Holographic Dark Energy Density and JBP Parametrization
NASA Astrophysics Data System (ADS)
Saadat, Hassan; Mousavi, S. N.; Saadat, A. M.
2011-09-01
In this article we consider the holographic dark energy density. We study dark energy density in Universe with arbitrary spatially curvature described by the Friedmann-Robertson-Walker metric. We use Jassal-Bagla-Padmanabhan parametrization to specify dark energy density.
G-corrected holographic dark energy model
NASA Astrophysics Data System (ADS)
Malekjani, M.; Honari-Jafarpour, M.
2013-08-01
Here we investigate the holographic dark energy model in the framework of FRW cosmology where the Newtonian gravitational constant, G, is varying with cosmic time. Using the complementary astronomical data which support the time dependency of G, the evolutionary treatment of EoS parameter and energy density of dark energy model are calculated in the presence of time variation of G. It has been shown that in this case, the phantom regime can be achieved at the present time. We also calculate the evolution of G-corrected deceleration parameter for holographic dark energy model and show that the dependency of G on the comic time can influence on the transition epoch from decelerated expansion to the accelerated phase. Finally we perform the statefinder analysis for G-corrected holographic model and show that this model has a shorter distance from the observational point in s- r plane compare with original holographic dark energy model.
Holographic dark energy models: a comparison from the latest observational data
Li, Miao; Li, Xiao-Dong; Wang, Shuang; Zhang, Xin E-mail: renzhe@mail.ustc.edu.cn E-mail: zhangxin@mail.neu.edu.cn
2009-06-01
The holographic principle of quantum gravity theory has been applied to the dark energy (DE) problem, and so far three holographic DE models have been proposed: the original holographic dark energy (HDE) model, the agegraphic dark energy (ADE) model, and the holographic Ricci dark energy (RDE) model. In this work, we perform the best-fit analysis on these three models, by using the latest observational data including the Union+CFA3 sample of 397 Type Ia supernovae (SNIa), the shift parameter of the cosmic microwave background (CMB) given by the five-year Wilkinson Microwave Anisotropy Probe (WMAP5) observations, and the baryon acoustic oscillation (BAO) measurement from the Sloan Digital Sky Survey (SDSS). The analysis shows that for HDE, χ{sub min}{sup 2} = 465.912; for RDE, χ{sub min}{sup 2} = 483.130; for ADE, χ{sub min}{sup 2} = 481.694. Among these models, HDE model can give the smallest χ{sup 2}{sub min}. Besides, we also use the Bayesian evidence (BE) as a model selection criterion to make a comparison. It is found that for HDE, ADE, and RDE, Δln BE = −0.86, −5.17, and −8.14, respectively. So, it seems that the HDE model is more favored by the observational data.
(m, n)-TYPE Holographic Dark Energy Models
NASA Astrophysics Data System (ADS)
Ling, Yi; Pan, Wen-Jian
2013-09-01
We construct (m, n)-type holographic dark energy models at a phenomenological level, which can be viewed as a generalization of agegraphic models with the conformal-like age as the holographic characteristic size. For some values of (m, n) the holographic dark energy can automatically evolve across ω = -1 into a phantom phase even without introducing an interaction between the dark energy and background matter. Our construction is also applicable to the holographic dark energy with generalized future event horizon as the characteristic size. Finally, we address the issue on the stability of our model and show that they are generally stable under the scalar perturbation.
Holographic dark matter and Higgs models.
Díaz-Cruz, J Lorenzo
2008-06-06
We propose a dark matter candidate within the class of models where electroweak symmetry breaking is triggered by a light composite Higgs boson. In these dual anti-de Sitter/conformal field theory models, the Higgs boson emerges as a holographic pseudo-Goldstone boson, while dark matter can be identified with a stable composite fermion X0. The effective Lagrangian description of the Higgs and X0-multiplets, including higher-dimensional operators, can be tested at future colliders (LHC, ILC) and through astrophysical signals (ultrahigh-energy cosmic rays). The expected mass of X0, mX0 < or approximately 4pif approximately O (TeV), satisfies the bounds extracted from the cosmological relic density, while the experimental searches for dark matter further constrains the possible models.
Holographic dark energy with cosmological constant
Hu, Yazhou; Li, Nan; Zhang, Zhenhui; Li, Miao E-mail: mli@itp.ac.cn E-mail: zhangzhh@mail.ustc.edu.cn
2015-08-01
Inspired by the multiverse scenario, we study a heterotic dark energy model in which there are two parts, the first being the cosmological constant and the second being the holographic dark energy, thus this model is named the ΛHDE model. By studying the ΛHDE model theoretically, we find that the parameters d and Ω{sub hde} are divided into a few domains in which the fate of the universe is quite different. We investigate dynamical behaviors of this model, and especially the future evolution of the universe. We perform fitting analysis on the cosmological parameters in the ΛHDE model by using the recent observational data. We find the model yields χ{sup 2}{sub min}=426.27 when constrained by Planck+SNLS3+BAO+HST, comparable to the results of the HDE model (428.20) and the concordant ΛCDM model (431.35). At 68.3% CL, we obtain −0.07<Ω{sub Λ0}<0.68 and correspondingly 0.04<Ω{sub hde0}<0.79, implying at present there is considerable degeneracy between the holographic dark energy and cosmological constant components in the ΛHDE model.
Holographic dark energy with cosmological constant
NASA Astrophysics Data System (ADS)
Hu, Yazhou; Li, Miao; Li, Nan; Zhang, Zhenhui
2015-08-01
Inspired by the multiverse scenario, we study a heterotic dark energy model in which there are two parts, the first being the cosmological constant and the second being the holographic dark energy, thus this model is named the ΛHDE model. By studying the ΛHDE model theoretically, we find that the parameters d and Ωhde are divided into a few domains in which the fate of the universe is quite different. We investigate dynamical behaviors of this model, and especially the future evolution of the universe. We perform fitting analysis on the cosmological parameters in the ΛHDE model by using the recent observational data. We find the model yields χ2min=426.27 when constrained by Planck+SNLS3+BAO+HST, comparable to the results of the HDE model (428.20) and the concordant ΛCDM model (431.35). At 68.3% CL, we obtain -0.07<ΩΛ0<0.68 and correspondingly 0.04<Ωhde0<0.79, implying at present there is considerable degeneracy between the holographic dark energy and cosmological constant components in the ΛHDE model.
Inflation via logarithmic entropy-corrected holographic dark energy model
NASA Astrophysics Data System (ADS)
Darabi, F.; Felegary, F.; Setare, M. R.
2016-12-01
We study the inflation in terms of the logarithmic entropy-corrected holographic dark energy (LECHDE) model with future event horizon, particle horizon, and Hubble horizon cut-offs, and we compare the results with those obtained in the study of inflation by the holographic dark energy HDE model. In comparison, the spectrum of primordial scalar power spectrum in the LECHDE model becomes redder than the spectrum in the HDE model. Moreover, the consistency with the observational data in the LECHDE model of inflation constrains the reheating temperature and Hubble parameter by one parameter of holographic dark energy and two new parameters of logarithmic corrections.
Time-Dependent Dark Energy Density and Holographic DE Model with Interaction
NASA Astrophysics Data System (ADS)
Saadat, H.; Saadat, A. M.
2011-05-01
In this article we consider holographic dark energy model with interaction and space curvature. We calculate cosmic scale factor by using the time-dependent dark energy density. Then we obtain phenomenological interaction between holographic dark energy and matter.
Planck constraints on holographic dark energy
Li, Miao; Zhang, Zhenhui; Li, Xiao-Dong; Ma, Yin-Zhe; Zhang, Xin E-mail: xiaodongli@kias.re.kr E-mail: zhangxin@mail.neu.edu.cn
2013-09-01
We perform a detailed investigation on the cosmological constraints on the holographic dark energy (HDE) model by using the Plank data. We find that HDE can provide a good fit to the Plank high-l (l ∼> 40) temperature power spectrum, while the discrepancy at l ≅ 20-40 found in the ΛCDM model remains unsolved in the HDE model. The Plank data alone can lead to strong and reliable constraint on the HDE parameter c. At the 68% confidence level (CL), we obtain c = 0.508 ± 0.207 with Plank+WP+lensing, favoring the present phantom behavior of HDE at the more than 2σ CL. By combining Plank+WP with the external astrophysical data sets, i.e. the BAO measurements from 6dFGS+SDSS DR7(R)+BOSS DR9, the direct Hubble constant measurement result (H{sub 0} = 73.8 ± 2.4 kms{sup −1}Mpc{sup −1}) from the HST, the SNLS3 supernovae data set, and Union2.1 supernovae data set, we get the 68% CL constraint results c = 0.484 ± 0.070, 0.474 ± 0.049, 0.594 ± 0.051, and 0.642 ± 0.066, respectively. The constraints can be improved by 2%-15% if we further add the Plank lensing data into the analysis. Compared with the WMAP-9 results, the Plank results reduce the error by 30%-60%, and prefer a phantom-like HDE at higher significant level. We also investigate the tension between different data sets. We find no evident tension when we combine Plank data with BAO and HST. Especially, we find that the strong correlation between Ω{sub m}h{sup 3} and dark energy parameters is helpful in relieving the tension between the Plank and HST measurements. The residual value of χ{sup 2}{sub Plank+WP+HST}−χ{sup 2}{sub Plank+WP} is 7.8 in the ΛCDM model, and is reduced to 1.0 or 0.3 if we switch the dark energy to w model or the holographic model. When we introduce supernovae data sets into the analysis, some tension appears. We find that the SNLS3 data set is in tension with all other data sets; for example, for the Plank+WP, WMAP-9 and BAO+HST, the corresponding Δχ{sup 2} is equal to 6
Planck constraints on holographic dark energy
NASA Astrophysics Data System (ADS)
Li, Miao; Li, Xiao-Dong; Ma, Yin-Zhe; Zhang, Xin; Zhang, Zhenhui
2013-09-01
We perform a detailed investigation on the cosmological constraints on the holographic dark energy (HDE) model by using the Plank data. We find that HDE can provide a good fit to the Plank high-l (l gtrsim 40) temperature power spectrum, while the discrepancy at l simeq 20-40 found in the ΛCDM model remains unsolved in the HDE model. The Plank data alone can lead to strong and reliable constraint on the HDE parameter c. At the 68% confidence level (CL), we obtain c = 0.508 ± 0.207 with Plank+WP+lensing, favoring the present phantom behavior of HDE at the more than 2σ CL. By combining Plank+WP with the external astrophysical data sets, i.e. the BAO measurements from 6dFGS+SDSS DR7(R)+BOSS DR9, the direct Hubble constant measurement result (H0 = 73.8 ± 2.4 kms-1Mpc-1) from the HST, the SNLS3 supernovae data set, and Union2.1 supernovae data set, we get the 68% CL constraint results c = 0.484 ± 0.070, 0.474 ± 0.049, 0.594 ± 0.051, and 0.642 ± 0.066, respectively. The constraints can be improved by 2%-15% if we further add the Plank lensing data into the analysis. Compared with the WMAP-9 results, the Plank results reduce the error by 30%-60%, and prefer a phantom-like HDE at higher significant level. We also investigate the tension between different data sets. We find no evident tension when we combine Plank data with BAO and HST. Especially, we find that the strong correlation between Ωmh3 and dark energy parameters is helpful in relieving the tension between the Plank and HST measurements. The residual value of χ2Plank+WP+HST-χ2Plank+WP is 7.8 in the ΛCDM model, and is reduced to 1.0 or 0.3 if we switch the dark energy to w model or the holographic model. When we introduce supernovae data sets into the analysis, some tension appears. We find that the SNLS3 data set is in tension with all other data sets; for example, for the Plank+WP, WMAP-9 and BAO+HST, the corresponding Δχ2 is equal to 6.4, 3.5 and 4.1, respectively. As a comparison, the Union2
A Note on Holographic Dark Energy with Varying c 2 Term
NASA Astrophysics Data System (ADS)
Sheykhi, A.; Ghaffari, S.; Roshanshah, N.
2017-03-01
We reconsider the holographic dark energy (HDE) model with a slowly time varying c 2(z) parameter in the energy density, namely ρ D=3{Mp2} c2(z)/L2, where L is the IR cutoff and z is the redshift parameter. As the system's IR cutoff we choose the Hubble radius and the Granda-Oliveros (GO) cutoffs. The latter inspired by the Ricci scalar curvature. We derive the evolution of the cosmological parameters such as the equation of state and the deceleration parameters as the explicit functions of the redshift parameter z. Then, we plot the evolutions of these cosmological parameters in terms of the redshift parameter during the history of the universe. Interestingly enough, we observe that by choosing L = H -1 as the IR cutoff for the HDE with time varying c 2(z) term, the present acceleration of the universe expansion can be achieved, even in the absence of interaction between dark energy and dark matter. This is in contrast to the usual HDE model with constant c 2 term, which leads to a wrong equation of state, namely that for dust w D =0, when the IR cutoff is chosen the Hubble radius.
Holographic vortices in the presence of dark matter sector
NASA Astrophysics Data System (ADS)
Rogatko, Marek; Wysokinski, Karol I.
2015-12-01
The dark matter seem to be an inevitable ingredient of the total matter configuration in the Universe and the knowledge how the dark matter affects the properties of superconductors is of vital importance for the experiments aimed at its direct detection. The homogeneous magnetic field acting perpendicularly to the surface of (2+1) dimensional s-wave holographic superconductor in the theory with dark matter sector has been modeled by the additional U(1)-gauge field representing dark matter and coupled to the Maxwell one. As expected the free energy for the vortex configuration turns out to be negative. Importantly its value is lower in the presence of dark matter sector. This feature can explain why in the Early Universe first the web of dark matter appeared and next on these gratings the ordinary matter forming cluster of galaxies has formed.
Holographic dark energy and late cosmic acceleration
NASA Astrophysics Data System (ADS)
Pavón, Diego
2007-06-01
It has been persuasively argued that the number of effective degrees of freedom of a macroscopic system is proportional to its area rather than to its volume. This entails interesting consequences for cosmology. Here we present a model based on this 'holographic principle' that accounts for the present stage of accelerated expansion of the Universe and significantly alleviates the coincidence problem also for non-spatially flat cosmologies. Likewise, we comment on a recently proposed late transition to a fresh decelerated phase.
Holographic Dark Energy Model with Interaction and Cosmological Constant in the Flat Space-Time
NASA Astrophysics Data System (ADS)
Saadat, Hassan
2012-06-01
In this paper we consider holographic dark energy model with interaction in the flat space-time with non-zero cosmological constant. We calculate cosmic scale factor and Hubble expansion parameter by using the time-dependent dark energy density. Then, we obtain phenomenological interaction between holographic dark energy and matter. We fixed our solution by using the observational data.
New holographic dark energy model inspired by the DGP braneworld
NASA Astrophysics Data System (ADS)
Sheykhi, A.; Dehghani, M. H.; Ghaffari, S.
2016-11-01
The energy density of the holographic dark energy (HDE) is based on the area law of entropy, and thus any modification of the area law leads to a modified holographic energy density. Inspired by the entropy expression associated with the apparent horizon of a Friedmann-Robertson-Walker (FRW) universe in DGP braneworld, we propose a new model for the HDE in the framework of DGP brane cosmology. We investigate the cosmological consequences of this new model and calculate the equation of state (EoS) parameter by choosing the Hubble radius, L = H-1, as the system’s IR cutoff. Our study show that, due to the effects of the extra dimension (bulk), the identification of IR cutoff with Hubble radius, can reproduce the present acceleration of the universe expansion. This is in contrast to the ordinary HDE in standard cosmology which leads to the zero EoS parameter in the case of choosing the Hubble radius as system’s IR cutoff in the absence of interaction between dark matter (DM) and dark energy (DE).
Reconstruction of interaction rate in holographic dark energy
NASA Astrophysics Data System (ADS)
Mukherjee, Ankan
2016-11-01
The present work is based on the holographic dark energy model with Hubble horizon as the infrared cut-off. The interaction rate between dark energy and dark matter has been reconstructed for three different parameterizations of the deceleration parameter. Observational constraints on the model parameters have been obtained by maximum likelihood analysis using the observational Hubble parameter data (OHD), type Ia supernovab data (SNe), baryon acoustic oscillation data (BAO) and the distance prior of cosmic microwave background (CMB) namely the CMB shift parameter data (CMBShift). The interaction rate obtained in the present work remains always positive and increases with expansion. It is very similar to the result obtained by Sen and Pavon [1] where the interaction rate has been reconstructed for a parametrization of the dark energy equation of state. Tighter constraints on the interaction rate have been obtained in the present work as it is based on larger data sets. The nature of the dark energy equation of state parameter has also been studied for the present models. Though the reconstruction is done from different parametrizations, the overall nature of the interaction rate is very similar in all the cases. Different information criteria and the Bayesian evidence, which have been invoked in the context of model selection, show that the these models are at close proximity of each other.
Variable modified Chaplygin gas in the holographic dark energy scenario
NASA Astrophysics Data System (ADS)
Chattopadhyay, Surajit; Debnath, Ujjal
2012-07-01
The holographic principle emerged in the context of black-holes, where it was noted that a local quantum field theory can not fully describe the black holes [1]. Some long standing debates regarding the time evolution of a system, where a black hole forms and then evaporates, played the key role in the development of the holographic principle [2,3,4]. The Chaplygin gas is characterized by an exotic equation of state p=-B/ρ. where B is a positive constant. Role of Chaplygin gas in the accelerated universe has been studied by several authors. The above mentioned equation of state has been modified to p=-B/ρ^{α}, where α lies between 0 and 1. This equation has been further modified to p=-A+B/ρ^{α}. This is called the modified Chaplygin gas. Debnath [5] introduced a variable modified Chaplygin gas by considering B as a function of scale factor a. In this work, we have considered that the universe is filled with normal matter and variable modified Chaplygin gas. Also we have considered the interaction between normal matter and variable modified Chaplygin gas in FRW universe. Then we have considered a correspondence between the holographic dark energy density and interacting variable modified Chaplygin gas energy density. Then we have reconstructed the potential of the scalar field which describes the variable modified Chaplygin cosmology References: [1] K. Enqvist, S. Hannested and M. S. Sloth, JCAP 2, 004 (2005). [2] L. Thorlocius, hep-th/0404098. [3] G. T. Hooft, gr-qc/9310026. [4] L. Susskind, J. Math. Phys. 36, 6377 (1995). [5] U. Debnath, Astrophys. Space Sci. 312, 295 (2007).
Entropy corrected holographic dark energy models in modified gravity
NASA Astrophysics Data System (ADS)
Jawad, Abdul; Azhar, Nadeem; Rani, Shamaila
We consider the power law and the entropy corrected holographic dark energy (HDE) models with Hubble horizon in the dynamical Chern-Simons modified gravity. We explore various cosmological parameters and planes in this framework. The Hubble parameter lies within the consistent range at the present and later epoch for both entropy corrected models. The deceleration parameter explains the accelerated expansion of the universe. The equation of state (EoS) parameter corresponds to quintessence and cold dark matter (ΛCDM) limit. The ωΛ‑ωΛ‧ approaches to ΛCDM limit and freezing region in both entropy corrected models. The statefinder parameters are consistent with ΛCDM limit and dark energy (DE) models. The generalized second law of thermodynamics remain valid in all cases of interacting parameter. It is interesting to mention here that our results of Hubble, EoS parameter and ωΛ‑ωΛ‧ plane show consistency with the present observations like Planck, WP, BAO, H0, SNLS and nine-year WMAP.
Contact term, its holographic description in QCD and dark energy
NASA Astrophysics Data System (ADS)
Zhitnitsky, Ariel R.
2012-08-01
In this work we study the well-known contact term, which is the key element in resolving the so-called U(1)A problem in QCD. We study this term using the dual holographic description. We argue that in the dual picture the contact term is saturated by the D2-branes which can be interpreted as the tunneling events in Minkowski space-time. We quote a number of direct lattice results supporting this identification. We also argue that the contact term receives a Casimir-like correction ˜(ΛQCDR)-1 rather than the naively expected exp(-ΛQCDR) when the Minkowski space-time R3,1 is replaced by a large but finite manifold with a size R. Such a behavior is consistent with other quantum field theory (QFT)-based computations when powerlike corrections are due to nontrivial properties of topological sectors of the theory. In holographic description, such a behavior is due to a massless Ramond-Ramond (RR) field living in the bulk of multidimensional space when powerlike corrections is a natural outcome of a massless RR field. In many respects, the phenomenon is similar to the Aharonov-Casher effect when the “modular electric field” can penetrate into a superconductor where the electric field is exponentially screened. The role of “modular operator” from the Aharonov-Casher effect is played by a large-gauge transformation operator T in four-dimensional QCD, resulting in the transparency of the system to topologically nontrivial pure gauge configurations. We discuss some profound consequences of our findings. In particular, we speculate that a slow variation of the contact term in expanding universe might be the main source of the observed dark energy.
NASA Astrophysics Data System (ADS)
Peng, Yan; Pan, Qiyuan; Liu, Yunqi
2017-02-01
We investigate holographic phase transitions with dark matter sector in the AdS soliton background away from the probe limit. In cases of weak backreaction, we find that the larger coupling parameter α makes the gap of condensation shallower and the critical chemical potential keeps as a constant. In contrast, for very heavy backreaction, the dark matter sector could affect the critical chemical potential and the order of phase transitions. We also find the jump of the holographic topological entanglement entropy corresponds to a first order transition between superconducting states in this model with dark matter sector. More importantly, for certain sets of parameters, we observe novel phenomenon of retrograde condensation. In a word, the dark matter sector provides richer physics in the phase structure and the holographic superconductor properties are helpful in understanding dark matter.
Probing interaction and spatial curvature in the holographic dark energy model
Li, Miao; Li, Xiao-Dong; Wang, Shuang; Wang, Yi; Zhang, Xin E-mail: renzhe@mail.ustc.edu.cn E-mail: wangyi@hep.physics.mcgill.ca
2009-12-01
In this paper we place observational constraints on the interaction and spatial curvature in the holographic dark energy model. We consider three kinds of phenomenological interactions between holographic dark energy and matter, i.e., the interaction term Q is proportional to the energy densities of dark energy (ρ{sub Λ}), matter (ρ{sub m}), and matter plus dark energy (ρ{sub m}+ρ{sub Λ}). For probing the interaction and spatial curvature in the holographic dark energy model, we use the latest observational data including the type Ia supernovae (SNIa) Constitution data, the shift parameter of the cosmic microwave background (CMB) given by the five-year Wilkinson Microwave Anisotropy Probe (WMAP5) observations, and the baryon acoustic oscillation (BAO) measurement from the Sloan Digital Sky Survey (SDSS). Our results show that the interaction and spatial curvature in the holographic dark energy model are both rather small. Besides, it is interesting to find that there exists significant degeneracy between the phenomenological interaction and the spatial curvature in the holographic dark energy model.
NASA Astrophysics Data System (ADS)
Reddy, D. R. K.; Raju, P.; Sobhanbabu, K.
2016-04-01
Five dimensional spherically symmetric space-time filled with two minimally interacting fields; matter and holographic dark energy components is investigated in a scalar tensor theory of gravitation proposed by Brans and Dicke (Phys. Rev. 124:925, 1961). To obtain a determinate solution of the highly non-linear field equations we have used (i) a relation between metric potentials and (ii) an equation of state which represents disordered radiation in five dimensional universe. The solution obtained represents a minimally interacting and radiating holographic dark energy model in five dimensional universe. Some physical and Kinematical properties of the model are, also, studied.
Holographic dark energy in Brans-Dicke theory with logarithmic correction
NASA Astrophysics Data System (ADS)
Sheykhi, A.; Karami, K.; Jamil, M.; Kazemi, E.; Haddad, M.
2012-03-01
In the derivation of holographic dark energy density, the area law of the black hole entropy plays a crucial role. However, the entropy-area relation can be modified from the inclusion of quantum effects, motivated from the loop quantum gravity, string theory and black hole physics. In this paper, we study cosmological implication of the interacting entropy-corrected holographic dark energy model in the framework of Brans-Dicke cosmology. We obtain the equation of state and the deceleration parameters of the entropy-corrected holographic dark energy in a non-flat Universe. As system's IR cutoff we choose the radius of the event horizon measured on the sphere of the horizon, defined as L = ar( t). We find out that when the entropy-corrected holographic dark energy is combined with the Brans-Dicke field, the transition from normal state where w D > -1 to the phantom regime where w D < -1 for the equation of state of interacting dark energy can be more easily achieved for than when resort to the Einstein field equations is made.
A Study of Holographic Dark Energy Models in Chern-Simon Modified Gravity
NASA Astrophysics Data System (ADS)
Ali, Sarfraz; Amir, M. Jamil
2016-12-01
This paper is devoted to study some holographic dark energy models in the context of Chern-Simon modified gravity by considering FRW universe. We analyze the equation of state parameter using Granda and Oliveros infrared cut-off proposal which describes the accelerated expansion of the universe under the restrictions on the parameter α. It is shown that for the accelerated expansion phase -1<ω _{Λ }<-1/3, the parameter α varies according as 1<α <2/3. Furthermore, for 0< α<1, the holographic energy and pressure density illustrates phantom-like theory of the evolution when ω Λ<-1. Also, we discuss the correspondence between the quintessence, K-essence, tachyon and dilaton field models and holographic dark energy models on similar fashion. To discuss the accelerated expansion of the universe, we explore the potential and the dynamics of quintessence, K-essence, tachyon and dilaton field models.
P-wave holographic superconductor/insulator phase transitions affected by dark matter sector
NASA Astrophysics Data System (ADS)
Rogatko, Marek; Wysokinski, Karol I.
2016-03-01
The holographic approach to building the p-wave superconductors results in three different models: the Maxwell-vector, the SU(2) Yang-Mills and the helical. In the probe limit approximation, we analytically examine the properties of the first two models in the theory with dark matter sector. It turns out that the effect of dark matter on the Maxwell-vector p-wave model is the same as on the s-wave superconductor studied earlier. For the non-Abelian model we study the phase transitions between p-wave holographic insulator/superconductor and metal/superconductor. Studies of marginally stable modes in the theory under consideration allow us to determine features of p-wave holographic droplet in a constant magnetic field. The dependence of the superconducting transition temperature on the coupling constant α to the dark matter sector is affected by the dark matter density ρD . For ρ D > ρ the transition temperature is a decreasing function of α. The critical chemical potential μ c for the quantum phase transition between insulator and metal depends on the chemical potential of dark matter μ D and for μ D = 0 is a decreasing function of α.
Holographic entanglement entropy in insulator/superconductor transitions with dark matter sector
NASA Astrophysics Data System (ADS)
Peng, Yan; Chen, Lu; Liu, Guohua
2016-05-01
We generalize the Stückelberg holographic superconductor model by including dark matter sector in the five-dimensional AdS soliton space-time beyond the probe limit. We study phase transitions with large charge of the scalar field through the condensation of the scalar operator and the holographic topological entanglement entropy of the system. We find that the entanglement entropy is a good probe of the order of phase transitions and second-order critical phase transition points. By investigating the behaviors of the entanglement entropy, we show that the larger coupling parameter α makes the first-order phase transition more difficult to happen. In all, we conclude that the entanglement entropy can be used to study the effects of the dark matter sector in this general insulator/superconductor system.
Viscous holographic dark energy universe with Nojiri-Odintsov cut-off
NASA Astrophysics Data System (ADS)
Khurshudyan, Martiros
2016-12-01
In this paper we consider a toy model of large scale universe, when one of the dark components is a generalized holographic DE with a Nojiri-Odintsov cut-off. On the other hand, we made another assumption concerning to the companion of considered DE model due to impossibility of exact parameterization of dark side of the large scale universe. In particular, we assume an inhomogeneous viscous dark fluid discussed in literature very actively, to be possible candidate for the companion. In addition to cosmographic analysis we discuss the results from Om and two point Om analysis and estimated present day values of statefinder parameters (r,s) and (ω^' }_{de}, ω_{de}). Moreover, validity of generalized second law of thermodynamics is studied showing that theoretical results are well consistent with observational data. Constraints on cosmological parameters are due to Planck 2015 experiments.
NASA Astrophysics Data System (ADS)
Katore, S. D.; Kapse, D. V.
2017-02-01
In this paper, we have studied the anisotropic and homogeneous Bianchi type-VI 0 Universe filled with dark matter and holographic dark energy components in the framework of general relativity and Lyra's geometry. The Einstein's field equations have been solved exactly by taking the expansion scalar ( 𝜃) in the model is proportional to the shear scalar ( σ). Some physical and kinematical properties of the models are also discussed.
On holographic dark energy in non-isotropic Universe with Brans-Dicke theory
NASA Astrophysics Data System (ADS)
Hossienkhani, H.
2016-07-01
A spatially homogeneous and anisotropic Bianchi type I Universe has been studied with the interacting holographic dark energy (HDE) in the framework of Brans-Dicke theory. At first, we obtain the equation of state parameter, the deceleration parameter and the evolution equation of the interacting HDE in BD theory. We find that, in this case, ω_{Λ} can cross the phantom line (ω_{Λ}>-1) and eventually the Universe approaches a de-Sitter phase of expansion (ω_{Λ}→-1). Then, we extend our study to the case of stability of the interacting HDE in BI Universe according to BD theory. In case of we find that the squared sound speed of the interacting HDE is either positive or negative. This implies that the interacting HDE in BD theory can lead to a stable Universe favored by observations at the present time in an anisotropic Universe.
Holographic dark energy in the DGP braneworld with Granda-Oliveros cutoff
NASA Astrophysics Data System (ADS)
Ghaffari, S.; Dehghani, M. H.; Sheykhi, A.
2014-06-01
We consider the holographic dark energy (HDE) model in the framework of the DGP braneworld with Granda-Oliveros infrared (IR) cutoff, L =(αH˙+βH2)-1/2. With this choice for IR cutoff, we are able to derive evolution of the cosmological parameters such as the equation of state and the deceleration parameters, w and q, as the functions of the redshift parameter z. As far as we know, most previous models of HDE presented in the literature, do not give analytically ω =ω(z) and q=q(z). We plot the evolution of these parameters versus z and discuss that the results are compatible with the recent observations. With suitably choosing the parameters, this model can exhibit a transition from deceleration to the acceleration around z≈0.6. Then we suggest a correspondence between the quintessence and tachyon scalar fields and HDE in the framework of the DGP braneworld. This correspondence allows us to reconstruct the evolution of the scalar fields and the scalar potentials. We also investigate the stability of the presented model by calculating the squared sound speed, vs2, whose sign determines the stability of the model. Our study shows that vs2 could be positive provided the parameters of the model are chosen suitably. In particular, for α>1, β>0, and α<1, β<0, we have vs2>0 during the history of the Universe, and so the stable dark-energy-dominated universe can be achieved. This is in contrast to the HDE in standard cosmology, which is unstable against background perturbations and so cannot lead to a stable dark- energy-dominated universe.
NASA Astrophysics Data System (ADS)
Gomes, J. N.; Wang, Qiaoling; Xia, Changyu
2017-04-01
We introduce the concept h-almost Ricci soliton which extends naturally the almost Ricci soliton by Pigola-Rigoli-Rimoldi-Setti and show that a compact nontrivial h-almost Ricci soliton of dimension no less than three with h having defined signal and constant scalar curvature is isometric to a standard sphere with the potential function well determined. We also consider the h-Ricci soliton which is a particular case of the h-almost Ricci soliton and a generalization of the Ricci soliton and give characterizations for a special class of gradient h-Ricci solitons.
Retro-causal Holographic Dark Energy Coherent Vacuum Super-Solid Tetrad Emergent Gravity
NASA Astrophysics Data System (ADS)
Sarfatti, Jack
2010-10-01
Frictionless irrotational flow in superfluid helium comes from the gradient of a single Goldstone phase in the spontaneous broken U1 symmetry ground state, so too the four gravity tetrad and six spin connection Einstein-Cartan 1-form fields come from eight SU3 Goldstone phases of the post-inflation macro-quantum coherent 4D super-solid ``world crystal lattice'' QCD vacuum superconductor. Wheeler-Feynman's advanced potential, Hoyle-Narlikar's future influence functional, Cramer's ``transaction'' and Aharonov's pre-selection history/post-selection destiny double quantum state vector lead to the hologram idea that our interior bulk accelerating comoving spacelike slice 3D cosmological metric expansion rate in conformal time is a dynamical 3D back-from-the-future (final cause) retro-causal holographic image of 2D surface fractional quantum statistical anyonic qubit patterns on our observer-dependent thermal future de Sitter (dS) event horizon whose asymptotically constant area/entropy is the reciprocal dark energy density.
NASA Astrophysics Data System (ADS)
Ranjit, Chayan; Rudra, Prabir
2016-10-01
The present work is based on the idea of an interacting framework of new holographic dark energy (HDE) with cold dark matter in the background of f(T) gravity. Here, we have considered the flat modified Friedmann universe for f(T) gravity which is filled with new HDE and dark matter. We have derived some cosmological parameters like deceleration parameter, equation of state (EoS) parameter, state-finder parameters, cosmographic parameters, Om parameter and graphically investigated the nature of these parameters for the above mentioned interacting scenario. The results are found to be consistent with the accelerating universe. Also, we have graphically investigated the trajectories in ω-ω‧ plane for different values of the interacting parameter and explored the freezing region and thawing region in ω-ω‧ plane. Finally, we have analyzed the stability of this model.
Zhang, Jing-Fei; Zhao, Ming-Ming; Li, Yun-He; Zhang, Xin E-mail: zhaomingmingsp@163.com E-mail: zhangxin@mail.neu.edu.cn
2015-04-01
The model of holographic dark energy (HDE) with massive neutrinos and/or dark radiation is investigated in detail. The background and perturbation evolutions in the HDE model are calculated. We employ the PPF approach to overcome the gravity instability difficulty (perturbation divergence of dark energy) led by the equation-of-state parameter w evolving across the phantom divide w=−1 in the HDE model with c<1. We thus derive the evolutions of density perturbations of various components and metric fluctuations in the HDE model. The impacts of massive neutrino and dark radiation on the CMB anisotropy power spectrum and the matter power spectrum in the HDE scenario are discussed. Furthermore, we constrain the models of HDE with massive neutrinos and/or dark radiation by using the latest measurements of expansion history and growth of structure, including the Planck CMB temperature data, the baryon acoustic oscillation data, the JLA supernova data, the Hubble constant direct measurement, the cosmic shear data of weak lensing, the Planck CMB lensing data, and the redshift space distortions data. We find that ∑ m{sub ν}<0.186 eV (95% CL) and N{sub eff}=3.75{sup +0.28}{sub −0.32} in the HDE model from the constraints of these data.
NASA Astrophysics Data System (ADS)
Sarkar, Sanjay
2014-08-01
The present work deals with the accretion of two minimally interacting fluids: dark matter and a hypothetical isotropic fluid as the holographic dark energy components onto black hole and wormhole in a spatially homogeneous and anisotropic Bianchi type-V universe. To obtain an exact solution of the Einstein's field equations, we use the assumption of linearly varying deceleration parameter. Solution describes effectively the actual acceleration and indicates a big rip type future singularity of the universe. We have studied the evolution of the mass of black hole and the wormhole embedded in this anisotropic universe in order to reproduce a stable universe protected against future-time singularity. It is observed that the accretion of these dark components leads to a gradual decrease and increase of black hole and wormhole mass respectively. Finally, we have found that contrary to our previous case (Sarkar in Astrophys. Space. Sci. 341:651, 2014a), the big rip singularity of the universe with a divergent Hubble parameter of this dark energy model may be avoided by a big trip.
Zhai, Zhong-Xu; Liu, Wen-Biao; Zhang, Tong-Jie E-mail: tjzhang@bnu.edu.cn
2011-08-01
The newly released observational H(z) data (OHD) is used to constrain Λ(t)CDM models as holographic and agegraphic dark energy. By the use of the length scale and time scale as the IR cut-off including Hubble horizon (HH), future event horizon (FEH), age of the universe (AU), and conformal time (CT), we achieve four different Λ(t)CDM models which can describe the present cosmological acceleration respectively. In order to get a comparison between such Λ(t)CDM models and standard ΛCDM model, we use the information criteria (IC), Om(z) diagnostic, and statefinder diagnostic to measure the deviations. Furthermore, by simulating a larger Hubble parameter data sample in the redshift range of 0.1 < z < 2.0, we get the improved constraints and more sufficient comparison. We show that OHD is not only able to play almost the same role in constraining cosmological parameters as SNe Ia does but also provides the effective measurement of the deviation of the DE models from standard ΛCDM model. In the holographic and agegraphic scenarios, the results indicate that the FEH is more preferable than HH scenario. However, both two time scenarios show better approximations to ΛCDM model than the length scenarios.
On a holographic dark energy model with a Nojiri-Odintsov cut-off in general relativity
NASA Astrophysics Data System (ADS)
Khurshudyan, Martiros
2016-07-01
In this paper we consider the models of the accelerated expanding large scale universe (according to general relativity) containing a generalized holographic dark energy with a Nojiri-Odintsov cut-off. The second component of the darkness is assumed to be the pressureless cold dark matter according to observed symmetries of the large scale universe. Moreover, we assume specific forms of the interaction between these two components and besides the cosmographic analysis, we discuss appropriate results from Om and Om3 analysis and organize a closer look to the models via the statefinder hierarchy analysis, too. In this way we study mainly impact of the interaction on the dynamics of the background of our universe (within specific forms of interaction). To complete the cosmographic analysis, the present day values of the statefinder parameters (r,s) and (ω^'_{de}, ω_{de}) has been estimated for all cases and the validity of the generalized second law of thermodynamics is demonstrated. Our study showed that theoretical results from considered phenomenological models are consistent with the available observational data and symmetries.
Algebraic Ricci solitons of three-dimensional Lorentzian Lie groups
NASA Astrophysics Data System (ADS)
Batat, W.; Onda, K.
2017-04-01
We study algebraic Ricci solitons of three-dimensional Lorentzian Lie groups. All algebraic Ricci solitons that we obtain are solvsolitons. In particular, we obtain new solitons on G2, G5, and G6, and we prove that, contrary to the Riemannian case, Lorentzian Ricci solitons need not be algebraic Ricci solitons.
NASA Astrophysics Data System (ADS)
Saha, Pameli; Debnath, Ujjal
2016-09-01
Here, we peruse cosmological usage of the most promising candidates of dark energy in the framework of f( T) gravity theory where T represents the torsion scalar teleparallel gravity. We reconstruct the different f( T) modified gravity models in the spatially flat Friedmann-Robertson-Walker universe according to entropy-corrected versions of the holographic and new agegraphic dark energy models in power-law and logarithmic corrections, which describe an accelerated expansion history of the universe. We conclude that the equation of state parameter of the entropy-corrected models can transit from the quintessence state to the phantom regime as indicated by recent observations or can lie entirely in the phantom region. Also, using these models, we investigate the different areas of the stability with the help of the squared speed of sound.
Discrete Ricci Flow in Higher Dimensions
2015-02-01
tessellation of the lattice spacetime . The symbols Vkk∗ in the left column completely characterize the hybrid polytope in the d–dimensional lattice. The first...regular sim- plexes, etc.). Finally, there are many similarities between RF and issues involved in evolving black hole spacetimes that we believe can...black hole solutions of the Einstein equations. In fact, the Einstein equations for a vacuum spacetime is just the Ricci tensor. First, Hamilton showed
NASA Astrophysics Data System (ADS)
Pasqua, Antonio; Chattopadhyay, Surajit; Assaf, Khudhair A.; Salako, Ines G.
2016-06-01
In this paper, we study the properties of the Holographic Dark Energy (HDE) model in the context of Kaluza-Klein (KK) cosmology with infrared cut-off given by the recently proposed by Granda-Oliveros cut-off, which contains a term proportional to the time derivative of the Hubble parameter and one proportional to the Hubble parameter squared. Moreover, this cut-off is characterized by two free parameters which are the proportional constants of the two terms of the cut-off. We derive the expression of the Equation of State (EoS) parameter ωD and of the deceleration parameter q for both non-interacting and interacting Dark Sectors and in the limiting case of a flat Dark Dominated Universe. Moreover, we study the squared speed of the sound vs2 and the statefinder diagnostic \\{r,s\\} in order to understand the cosmological properties of the model considered. We also develop a correspondence between the model considered and three scalar field models: the tachyon, the k-essence and the quintessence ones.
Comparison of dark energy models after Planck 2015
NASA Astrophysics Data System (ADS)
Xu, Yue-Yao; Zhang, Xin
2016-11-01
We make a comparison for ten typical, popular dark energy models according to their capabilities of fitting the current observational data. The observational data we use in this work include the JLA sample of type Ia supernovae observation, the Planck 2015 distance priors of cosmic microwave background observation, the baryon acoustic oscillations measurements, and the direct measurement of the Hubble constant. Since the models have different numbers of parameters, in order to make a fair comparison, we employ the Akaike and Bayesian information criteria to assess the worth of the models. The analysis results show that, according to the capability of explaining observations, the cosmological constant model is still the best one among all the dark energy models. The generalized Chaplygin gas model, the constant w model, and the α dark energy model are worse than the cosmological constant model, but still are good models compared to others. The holographic dark energy model, the new generalized Chaplygin gas model, and the Chevalliear-Polarski-Linder model can still fit the current observations well, but from an economically feasible perspective, they are not so good. The new agegraphic dark energy model, the Dvali-Gabadadze-Porrati model, and the Ricci dark energy model are excluded by the current observations.
Ricci solitons on low-dimensional generalized symmetric spaces
NASA Astrophysics Data System (ADS)
Calvaruso, Giovanni; Rosado, Eugenia
2017-02-01
We consider three- and four-dimensional pseudo-Riemannian generalized symmetric spaces, whose invariant metrics were explicitly described in Černý and Kowalski (1982). While four-dimensional pseudo-Riemannian generalized symmetric spaces of types A, C and D are algebraic Ricci solitons, the ones of type B are not so. The Ricci soliton equation for their metrics yields a system of partial differential equations. Solving such system, we prove that almost all the four-dimensional pseudo-Riemannian generalized symmetric spaces of type B are Ricci solitons. These examples show some deep differences arising for the Ricci soliton equation between the Riemannian and the pseudo-Riemannian cases, as any homogeneous Riemannian Ricci soliton is algebraic Jablonski (2015). We also investigate three-dimensional generalized symmetric spaces of any signature and prove that they are Ricci solitons.
A MAGNIFIED GLANCE INTO THE DARK SECTOR: PROBING COSMOLOGICAL MODELS WITH STRONG LENSING IN A1689
Magaña, Juan; Motta, V.; Cárdenas, Victor H.; Verdugo, T.; Jullo, Eric E-mail: veronica.motta@uv.cl E-mail: tomasverdugo@gmail.com
2015-11-01
In this paper we constrain four alternative models to the late cosmic acceleration in the universe: Chevallier–Polarski–Linder (CPL), interacting dark energy (IDE), Ricci holographic dark energy (HDE), and modified polytropic Cardassian (MPC). Strong lensing (SL) images of background galaxies produced by the galaxy cluster Abell 1689 are used to test these models. To perform this analysis we modify the LENSTOOL lens modeling code. The value added by this probe is compared with other complementary probes: Type Ia supernovae (SN Ia), baryon acoustic oscillations (BAO), and cosmic microwave background (CMB). We found that the CPL constraints obtained for the SL data are consistent with those estimated using the other probes. The IDE constraints are consistent with the complementary bounds only if large errors in the SL measurements are considered. The Ricci HDE and MPC constraints are weak, but they are similar to the BAO, SN Ia, and CMB estimations. We also compute the figure of merit as a tool to quantify the goodness of fit of the data. Our results suggest that the SL method provides statistically significant constraints on the CPL parameters but is weak for those of the other models. Finally, we show that the use of the SL measurements in galaxy clusters is a promising and powerful technique to constrain cosmological models. The advantage of this method is that cosmological parameters are estimated by modeling the SL features for each underlying cosmology. These estimations could be further improved by SL constraints coming from other galaxy clusters.
Dilatonic non-linear sigma models and Ricci flow extensions
NASA Astrophysics Data System (ADS)
Carfora, M.; Marzuoli, A.
2016-09-01
We review our recent work describing, in terms of the Wasserstein geometry over the space of probability measures, the embedding of the Ricci flow in the renormalization group flow for dilatonic non-linear sigma models.
NASA Astrophysics Data System (ADS)
Yu, Dan; Liu, Hongpeng; Geng, Yaohui; Wang, Weibo; Zhao, Yuanyuan
2014-11-01
Photochemical radical polymerization in phenathrenequinone doped poly(methyl methacrylate) photopolymer are investigated theoretically and experimentally under consecutive exposure. The detailed photochemical mechanisms are analyzed. Based on the rate equations of photochemical reactions, the diffusion models with nonlocal response are proposed to describe the kinetic process of radical polymerization and the significance of photochemical processes for the grating formation. In experiments, the temporal evolution of diffraction efficiency in grating formation is measured under consecutive exposure and after exposure. The percentages of these radical polymerizations, namely the polymerization of PQ with matrix, the bimolecular combination of MMA molecules, and the disproportionation of MMA molecules, are extracted quantitatively by comparing theory with experiments. It is indicated that the polymerization of PQ with matrix is primary photochemical process which dominated the grating formation under consecutive exposure. In this period, the contribution of chain polymerization of MMA radicals is weak for the grating formation. After reaching the peak values of grating strength, the influence of the free MMA molecules and photoproduct macromolecules on the grating decay is discussed in a long-term period. The diffusion coefficients of MMA and photoproduct are extracted by fitting the curves using double exponential function. MMA’s diffusion contributed to the fast decay process of grating after exposure and photoproduct’s diffusion contributed to the slow and long decay of grating. The results break previous understanding about the diffusion of single photoproduct macromolecules lead to the dark decay of grating. This investigation can provide a significant foundation for improving modulation depth and long-term stability by photochemical mechanism.
Karami, K.
2010-01-01
Author of ref. 1, M.R. Setare (JCAP 01 (2007) 023), by redefining the event horizon measured from the sphere of the horizon as the system's IR cut-off for an interacting holographic dark energy model in a non-flat universe, showed that the generalized second law of thermodynamics is satisfied for the special range of the deceleration parameter. His paper includes an erroneous calculation of the entropy of the cold dark matter. Also there are some missing terms and some misprints in the equations of his paper. Here we present that his conclusion is not true and the generalized second law is violated for the present time independently of the deceleration parameter.
NASA Astrophysics Data System (ADS)
Sutcliffe, Paul M.
Skyrmions are topological solitons that describe baryons within a nonlinear theory of pions. In holographic QCD, baryons correspond to topological solitons in a bulk theory with an extra spatial dimension: thus the three-dimensional Skyrmion lifts to a four-dimensional holographic Skyrmion in the bulk. We begin this review with a description of the simplest example of this correspondence, where the holographic Skyrmion is exactly the self-dual Yang-Mills instanton in flat space. This places an old result of Atiyah and Manton within a holographic framework and reveals that the associated Skyrme model extends the nonlinear pion theory to include an infinite tower of vector mesons, with specific couplings for a BPS theory. We then describe the more complicated curved space version that arises from the string theory construction of Sakai and Sugimoto. The basic concepts remain the same but the technical difficulty increases as the holographic Skyrmion is a curved space version of the Yang-Mills instanton, so self-duality and integrability are lost. Finally, we turn to a low-dimensional analogue of holographic Skyrmions, where aspects such as multi-baryons and finite baryon density are amenable to both numerical computation and an approximate analytic treatment.
NASA Astrophysics Data System (ADS)
Odhner, Jefferson E.
2016-07-01
Holographic optical elements (HOEs) work on the principal of diffraction and can in some cases replace conventional optical elements that work on the principal of refraction. An HOE can be thinner, lighter, can have more functionality, and can be lower cost than conventional optics. An HOE can serve as a beam splitter, spectral filter, mirror, and lens all at the same time. For a single wavelength system, an HOE can be an ideal solution but they have not been widely accepted for multispectral systems because they suffer from severe chromatic aberration. A refractive optical system also suffers from chromatic aberration but it is generally not as severe. To color correct a conventional refractive optical system, a flint glass and a crown glass are placed together such that the color dispersion of the flint and the crown cancel each other out making an achromatic lens (achromat) and the wavelengths all focus to the same point. The color dispersion of refractive lenses and holographic lenses are opposite from each other. In a diffractive optical system, long wavelengths focus closer (remember for HOEs: RBM "red bends more") than nominal focus while shorter wavelengths focus further out. In a refractive optical system, it is just the opposite. For this reason, diffractives can be incorporated into a refractive system to do the color correction and often cut down on the number of optical elements used [1.]. Color correction can also be achieved with an all-diffractive system by combining a holographic optical element with its conjugate. In this way the color dispersion of the first holographic optical element can be cancelled by the color dispersion of the second holographic optic. It is this technique that will be exploited in this paper to design a telescope made entirely of holographic optical elements. This telescope could be more portable (for field operations) the same technique could be used to make optics light enough for incorporation into a UAV.
Topologically massive gravity and Ricci-Cotton flow
NASA Astrophysics Data System (ADS)
Lashkari, Nima; Maloney, Alexander
2011-05-01
We consider topologically massive gravity (TMG), which is three-dimensional general relativity with a cosmological constant and a gravitational Chern-Simons term. When the cosmological constant is negative the theory has two potential vacuum solutions: anti-de Sitter space and warped anti-de Sitter space. The theory also contains a massive graviton state which renders these solutions unstable for certain values of the parameters and boundary conditions. We study the decay of these solutions due to the condensation of the massive graviton mode using Ricci-Cotton flow, which is the appropriate generalization of Ricci flow to TMG. When the Chern-Simons coupling is small the AdS solution flows to warped AdS by the condensation of the massive graviton mode. When the coupling is large the situation is reversed, and warped AdS flows to AdS. Minisuperspace models are constructed where these flows are studied explicitly.
Spectral functionals, nonholonomic Dirac operators, and noncommutative Ricci flows
Vacaru, Sergiu I.
2009-07-15
We formulate a noncommutative generalization of the Ricci flow theory in the framework of spectral action approach to noncommutative geometry. Grisha Perelman's functionals are generated as commutative versions of certain spectral functionals defined by nonholonomic Dirac operators and corresponding spectral triples. We derive the formulas for spectral averaged energy and entropy functionals and state the conditions when such values describe (non)holonomic Riemannian configurations.
Saldin, D.K. ); de Andres, P.L. )
1990-03-12
We propose a new electron holographic scheme for the three-dimensional imaging of the atomic environment of disordered adsorbate atoms on a crystal surface, in which the object acts as its own beam splitter. The technique may be regarded as a direct method in low-energy electron diffraction, or even, in a sense, as a form of lensless electron microscopy.''
NASA Astrophysics Data System (ADS)
Anninos, Dionysios; Anous, Tarek; Denef, Frederik; Peeters, Lucas
2015-04-01
We establish the existence of stable and metastable stationary black hole bound states at finite temperature and chemical potentials in global and planar four-dimensional asymptotically anti-de Sitter space. We determine a number of features of their holographic duals and argue they represent structural glasses. We map out their thermodynamic landscape in the probe approximation, and show their relaxation dynamics exhibits logarithmic aging, with aging rates determined by the distribution of barriers.
Labeling spherically symmetric spacetimes with the Ricci tensor
NASA Astrophysics Data System (ADS)
Ferrando, Joan Josep; Sáez, Juan Antonio
2017-02-01
We complete the intrinsic characterization of spherically symmetric solutions partially accomplished in a previous paper (Ferrando and Sáez 2010 Class. Quantum Grav. 27 205024). In this approach we consider every compatible algebraic type of the Ricci tensor, and we analyze specifically the conformally flat case for perfect fluid and Einstein–Maxwell solutions. As a direct application we obtain the ideal labeling (exclusively involving explicit concomitants of the metric tensor) of the Schwarzschild interior metric and the Vaidya solution. The Stephani universes and some significative subfamilies are also characterized.
NASA Astrophysics Data System (ADS)
Clube, Francis S.; Gray, Simon; Struchen, Denis; Tisserand, Jean-Claude; Malfoy, Stephane; Darbellay, Yves
1995-09-01
Holographic mask aligners represent the latest addition to commercially available lithographic technologies. Their combination of very high resolution (< 0.5 micrometers ) and very large exposure field brings a new capability to the microelectronics industry, especially for the manufacture of flat panel displays. The machine is fully automated and includes a scanning laser illumination system, a dynamic focus system permitting patterns to be printed over poor-flatness substrates, and an alignment system providing 0.3-micrometers overlay accuracy. A higher-accuracy alignment system under development demonstrates 50-nm measurement accuracy. A step-and-repeat hologram recording method enables tighter control of feature linewidth.
NASA Astrophysics Data System (ADS)
Ian, Richard; King, Elisabeth
1988-01-01
Proposed is an exploratory study to verify the feasibility of an inexpensive micro-climate control system for both marine and freshwater pond and tank aquaculture, offering good control over water temperature, incident light flux, and bandwidth, combined with good energy efficiency. The proposed control system utilizes some familiar components of passive solar design, together with a new holographic glazing system which is currently being developed by, and proprietary to Advanced Environmental Research Group (AERG). The use of solar algae ponds and tanks to warm and purify water for fish and attached macroscopic marine algae culture is an ancient and effective technique, but limited seasonally and geographically by the availability of sunlight. Holographic Diffracting Structures (HDSs) can be made which passively track, accept and/or reject sunlight from a wide range of altitude and azimuth angles, and redirect and distribute light energy as desired (either directly or indirectly over water surface in an enclosed, insulated structure), effectively increasing insolation values by accepting sunlight which would not otherwise enter the structure.
NASA Astrophysics Data System (ADS)
Yi, Piljin
We review baryons in the D4-D8 holographic model of low energy QCD, with the large Nc and the large't Hooft coupling limit. The baryon is identified with a bulk soliton of a unit Pontryagin number, which from the four-dimensional viewpoint translates to a modified Skyrmion dressed by condensates of spin one mesons. We explore classical properties and find that the baryon in the holographic limit is amenable to an effective field theory description. We also present a simple method to capture all leading and subleading interactions in the 1/Nc and the derivative expansions. An infinitely predictive model of baryon-meson interactions is thus derived, although one may trust results only for low energy processes, given various approximations in the bulk. We showcase a few comparisons to experiments, such as the leading axial couplings to pions, the leading vector-like coupling, and a qualitative prediction of the electromagnetic vector dominance that involves the entire tower of vector mesons.
NASA Astrophysics Data System (ADS)
Palais, Joseph C.; Miller, Mark E.
1996-09-01
A unique method for the construction and display of a 3D holographic movie is developed. An animated film is produced by rotating a 3D object in steps between successive holographic exposures. Strip holograms were made on 70-mm AGFA 8E75 Holotest roll film. Each hologram was about 11-mm high and 55-mm high and 55-mm wide. The object was rotated 2 deg between successive exposures. A complete cycle of the object motion was recorded on 180 holograms using the lensless Fourier transform construction. The ends of the developed film were spliced together to produce a continuous loop. Although the film moves continuously on playback and there is not shutter, there is no flicker or image displacement because of the Fourier transform hologram construction, as predicted by the theoretical analysis. The movie can be viewed for an unlimited time because the object motion is cyclical and the film is continuous. The film is wide enough such that comfortable viewing with both eyes is possible, enhancing the 3D effect. Viewers can stand comfortably away from the film since no viewing slit or aperture is necessary. Several people can simultaneously view the movie.
Random holographic "large worlds" with emergent dimensions
NASA Astrophysics Data System (ADS)
Trugenberger, Carlo A.
2016-11-01
I propose a random network model governed by a Gaussian weight corresponding to Ising link antiferromagnetism as a model for emergent quantum space-time. In this model, discrete space is fundamental, not a regularization; its spectral dimension ds is not a model input but is, rather, completely determined by the antiferromagnetic coupling constant. Perturbative terms suppressing triangles and favoring squares lead to locally Euclidean ground states that are Ricci flat "large worlds" with power-law extension. I then consider the quenched graphs of lowest energy for ds=2 and ds=3 , and I show how quenching leads to the spontaneous emergence of embedding spaces of Hausdorff dimension dH=4 and dH=5 , respectively. One of the additional, spontaneous dimensions can be interpreted as time, causality being an emergent property that arises in the large N limit (with N the number of vertices). For ds=2 , the quenched graphs constitute a discrete version of a 5D-space-filling surface with a number of fundamental degrees of freedom scaling like N2 /5, a graph version of the holographic principle. These holographic degrees of freedom can be identified with the squares of the quenched graphs, which, being triangle-free, are the fundamental area (or loop) quanta.
Lorentzian three-metrics with degenerate Ricci tensors
NASA Astrophysics Data System (ADS)
McManus, Des J.
1995-03-01
A classification of Lorentzian three-metrics whose Ricci tensor satisfies Rij=λ1gij+λ2vivj with λ1 and λ2(≠0) constant where vivi=κ(=0 or ±1) is given. An explicit coordinate representation is given for all the metrics that admit a G4 group as their maximal isometry group. Those metrics that admit a G3 as their maximal isometry group belong to either Bianchi class VI0, or VII0, or VIII, or IX when κ ≠ 0, and to either Bianchi class III, or IV, or VI0, VIh, or VIII when κ=0. An explicit coordinate representation is given for all the inhomogeneous solutions in the case κ ≠ 0.
Science and Faith for promoting the Gospel: Matteo Ricci and Gerbert of Aurillac
NASA Astrophysics Data System (ADS)
Sigismondi, Costantino
Matteo Ricci (1562-1610), Jesuit and Gerbert of Aurillac (938-1003), Benedictin were outstanding scientisits for their times; astronomers and geographers. Their contribution on the dialogue between cultures is evidenced. For Matteo Ricci and his followers the scientific culture become a support for the evangelization, as a mean to help the chinese society and to promote it. Chinese nowadays are still grateful to Matteo Ricci, Li Ma To. Gerbert of Aurillac enjoyed the period of time when Arabs and Christians were in peaceful contact during his permanence in Catalonia. He left his intellectual heritage to Europe, even after the fall of this favorable period.
Linder, Eric V.
2004-04-01
The physical process leading to the acceleration of the expansion of the universe is unknown. It may involve new high energy physics or extensions to gravitation. Calling this generically dark energy, we examine the consistencies and relations between these two approaches, showing that an effective equation of state function w(z) is broadly useful in describing the properties of the dark energy. A variety of cosmological observations can provide important information on the dynamics of dark energy and the future looks bright for constraining dark energy, though both the measurements and the interpretation will be challenging. We also discuss a more direct relation between the spacetime geometry and acceleration, via ''geometric dark energy'' from the Ricci scalar, and superacceleration or phantom energy where the fate of the universe may be more gentle than the Big Rip.
Haba, Kazumoto; Matsuzaki, Shinya; Yamawaki, Koichi
2010-09-01
Technidilaton, a pseudo-Nambu-Goldstone boson of scale symmetry, was predicted long ago in the scale-invariant/walking/conformal technicolor (SWC-TC) as a remnant of the (approximate) scale symmetry associated with the conformal fixed point, based on the conformal gauge dynamics of ladder Schwinger-Dyson (SD) equation with nonrunning coupling. We study the technidilaton as a flavor-singlet bound state of technifermions by including the technigluon condensate (tGC) effect into the previous (bottom-up) holographic approach to the SWC-TC, a deformation of the holographic QCD with {gamma}{sub m{approx_equal}}0 by large anomalous dimension {gamma}{sub m{approx_equal}}1. With including a bulk scalar field corresponding to the gluon condensate, we first improve the operator product expansion of the current correlators so as to reproduce gluonic 1/Q{sup 4} term both in QCD and SWC-TC. We find in QCD about 10% (negative) contribution of gluon condensate to the {rho} meson mass. We also calculate the oblique electroweak S-parameter in the presence of the effect of the tGC and find that for the fixed value of S the tGC effects dramatically reduce the flavor-singlet scalar (technidilaton) mass M{sub TD} (in the unit of F{sub {pi}}), while the vector and axial-vector masses M{sub {rho}}and M{sub a{sub 1}} are rather insensitive to the tGC, where F{sub {pi}}is the decay constant of the technipion. If we use the range of values of tGC implied by the ladder SD analysis of the nonperturbative scale anomaly in the large N{sub f} QCD near the conformal window, the phenomenological constraint S{approx_equal}0.1 predicts the technidilaton mass M{sub TD{approx}}600 GeV which is within reach of LHC discovery.
A New Class of Almost Ricci Solitons and Their Physical Interpretation
2016-01-01
We establish a link between a connection symmetry, called conformal collineation, and almost Ricci soliton (in particular Ricci soliton) in reducible Ricci symmetric semi-Riemannian manifolds. As a physical application, by investigating the kinematic and dynamic properties of almost Ricci soliton manifolds, we present a physical model of imperfect fluid spacetimes. This model gives a general relation between the physical quantities (u, μ, p, α, η, σij) of the matter tensor of the field equations and does not provide any exact solution. Therefore, we propose further study on finding exact solutions of our viscous fluid physical model for which it is required that the fluid velocity vector u be tilted. We also suggest two open problems. PMID:28044145
The Wasserstein geometry of nonlinear σ models and the Hamilton-Perelman Ricci flow
NASA Astrophysics Data System (ADS)
Carfora, Mauro
Nonlinear sigma models are quantum field theories describing, in the large deviation sense, random fluctuations of harmonic maps between a Riemann surface and a Riemannian manifold. Via their formal renormalization group analysis, they provide a framework for possible generalizations of the Hamilton-Perelman Ricci flow. By exploiting the heat kernel embedding introduced by Gigli and Mantegazza, we show that the Wasserstein geometry of the space of probability measures over Riemannian metric measure spaces provides a natural setting for discussing the relation between nonlinear sigma models and Ricci flow theory. In particular, we analyze the embedding of Ricci flow into a heat kernel renormalization group flow for dilatonic nonlinear sigma models, and characterize a non-trivial generalization of the Hamilton-Perelman version of the Ricci flow. We discuss in detail the monotonicity and gradient flow properties of this extended flow.
Aharony, Ofer; Kutasov, David; Lunin, Oleg; Sonnenschein, Jacob; Yankielowicz, Shimon
2010-11-15
We study a brane configuration of D4-branes and NS5-branes in weakly coupled type IIA string theory, which describes in a particular limit d=4 N=1 SU(N+p) supersymmetric QCD with 2N flavors and a quartic superpotential. We describe the geometric realization of the supersymmetric vacuum structure of this gauge theory. We focus on the confining vacua of the gauge theory, whose holographic description is given by the MQCD brane configuration in the near-horizon geometry of N D4-branes. This description, which gives an embedding of MQCD into a field theory decoupled from gravity, is valid for 1<
An upper diameter bound for compact Ricci solitons with application to the Hitchin-Thorpe inequality
NASA Astrophysics Data System (ADS)
Tadano, Homare
2017-02-01
In this article, stimulated by Fernández-López and García-Río, we shall give an upper diameter bound for compact shrinking Ricci solitons in terms of the range of the scalar curvature, as well as in terms of the range of the potential function. As an application, we shall provide some new sufficient conditions for compact four-dimensional shrinking Ricci solitons to satisfy the Hitchin-Thorpe inequality.
Ricci collineation vectors in fluid space-times
Tsamparlis, M. ); Mason, D.P. )
1990-07-01
The properties of fluid space-times that admit a Ricci collineation vector (RCV) parallel to the fluid unit four-velocity vector {ital u}{sup {ital a}} are briefly reviewed. These properties are expressed in terms of the kinematic quantities of the timelike congruence generated by {ital u}{sup {ital a}}. The cubic equation derived by Oliver and Davis (Ann. Inst. Henri Poincare {bold 30}, 339 (1979)) for the equation of state {ital p}={ital p}({mu}) of a perfect fluid space-time that admits an RCV, which does not degenerate to a Killing vector, is solved for physically realistic fluids. Necessary and sufficient conditions for a fluid space-time to admit a spacelike RCV parallel to a unit vector {ital n}{sup {ital a}} orthogonal to {ital u}{sup {ital a}} are derived in terms of the expansion, shear, and rotation of the spacelike congruence generated by {ital n}{sup {ital a}}. Perfect fluid space-times are studied in detail and analogues of the results for timelike RCVs parallel to {ital u}{sup {ital a}} are obtained. Properties of imperfect fluid space-times for which the energy flux vector {ital q}{sup {ital a}} vanishes and {ital n}{sup {ital a}} is a spacelike eigenvector of the anisotropic stress tensor {pi}{sub {ital ab}} are derived. Fluid space-times with anisotropic pressure are discussed as a special case of imperfect fluid space-times for which {ital n}{sup {ital a}} is an eigenvector of {pi}{sub {ital ab}}.
NASA Astrophysics Data System (ADS)
Zhou, Gan; An, Xin; Pu, Allen; Psaltis, Demetri; Mok, Fai H.
1999-11-01
The holographic disc is a high capacity, disk-based data storage device that can provide the performance for next generation mass data storage needs. With a projected capacity approaching 1 terabit on a single 12 cm platter, the holographic disc has the potential to become a highly efficient storage hardware for data warehousing applications. The high readout rate of holographic disc makes it especially suitable for generating multiple, high bandwidth data streams such as required for network server computers. Multimedia applications such as interactive video and HDTV can also potentially benefit from the high capacity and fast data access of holographic memory.
Friedmann Propulsion in an Flat Holographic Universe
NASA Astrophysics Data System (ADS)
Binder, Bernd
2008-01-01
Because of inversion symmetries in holographic systems, the spatial compression of lower-dimensional holographic memory leads to an expansion of the holographic image and vice versa (scaling duality), where the geometric mean between the small quantum memory and cosmic image scale defines the inversion scale, the unit scale to normalize the global holographic currents of momentum exchange. Assigning to the cosmic image (bulk) a 4d, to the quantum memory (baryon) a 2d, and to the inversion scale a 3d spherical topology, the cosmic critical density in the flat FRW cosmic test model corresponds to 1 memory unit (baryon). Otherwise, if we expect expansion driven by 3d Einstein gravity on all scales, we get the well known cosmic ``dark matter'' deficit of 96% or 0.04 baryons per unit volume. The cosmic deficit or quantum excess is assigned by Gauss law to the topological ratio 4d bulk surface S3 to 2d quantum surface S1, which dilutes gravity or the mass density by the dimensionless factor 0.04~S3/2/S13 = 1/(8π) leading to a theoretical Hubble parameter of 73.2 kms-1 Mpc-1. Regarding propulsion based on fractional linear transforms mapping the quantum compression by inversion to a cosmic expansion, the anisotropic transform resembles the Alcubierre mechanism if expansion is behind and the compression ahead of the spaceship.
Constraints on holographic cosmologies from strong lensing systems
Cárdenas, Víctor H.; Bonilla, Alexander; Motta, Verónica; Campo, Sergio del E-mail: alex.bonilla@uv.cl E-mail: sdelcamp@ucv.cl
2013-11-01
We use strongly gravitationally lensed (SGL) systems to put additional constraints on a set of holographic dark energy models. Data available in the literature (redshift and velocity dispersion) is used to obtain the Einstein radius and compare it with model predictions. We found that the ΛCDM is the best fit to the data. Although a preliminary statistical analysis seems to indicate that two of the holographic models studied show interesting agreement with observations, a stringent test lead us to the result that neither of the holographic models are competitive with the ΛCDM. These results highlight the importance of Strong Lensing measurements to provide additional observational constraints to alternative cosmological models, which are necessary to shed some light into the dark universe.
Hannagan, Thomas; Dupoux, Emmanuel; Christophe, Anne
2011-01-01
In this article, we apply a special case of holographic representations to letter position coding. We translate different well-known schemes into this format, which uses distributed representations and supports constituent structure. We show that in addition to these brain-like characteristics, performances on a standard benchmark of behavioral effects are improved in the holographic format relative to the standard localist one. This notably occurs because of emerging properties in holographic codes, like transposition and edge effects, for which we give formal demonstrations. Finally, we outline the limits of the approach as well as its possible future extensions.
The Law of Unintended Consequences Revisited: The Case of Ricci v. DeStefano
ERIC Educational Resources Information Center
Vedder, Richard; Denhart, Matthew; Malesick, Michael; Templeton, Jordan
2009-01-01
Deciding it necessary to review the earlier ruling of the Second Circuit court, on January 9, 2009 the U.S. Supreme Court granted certiorari in the case "Ricci v. DeStefano." The case originates from New Haven, Connecticut where a group of firefighters argue that city officials violated their Title VII rights by dismissing the results of…
Optical scanning holographic microscopy
NASA Astrophysics Data System (ADS)
Poon, Ting-Chung; Doh, Kyu B.; Schilling, Bradley W.; Wu, Ming H.; Shinoda, Kazunori K.; Suzuki, Yoshiji
1995-03-01
We first review a newly developed 3D imaging technique called optical scanning holography (OSH), and discuss recording and reconstruction of a point object using the principle of OSH. We then derive 3D holographic magnification, using three points configured as a 3D object. Finally, we demonstrated 3D imaging capability of OSH by holographically recording two planar objects at different depths and reconstructing the hologram digitally.
NASA Technical Reports Server (NTRS)
Preston, K., Jr.
1972-01-01
The characteristics of the holographic logic computer are discussed. The holographic operation is reviewed from the Fourier transform viewpoint, and the formation of holograms for use in performing digital logic are described. The operation of the computer with an experiment in which the binary identity function is calculated is discussed along with devices for achieving real-time performance. An application in pattern recognition using neighborhood logic is presented.
Cosmological model favored by the holographic principle
NASA Astrophysics Data System (ADS)
Dymnikova, Irina; Dobosz, Anna; Sołtysek, Bożena
2016-03-01
We present a regular spherically symmetric cosmological model of the Lemaitre class distinguished by the holographic principle as the thermodynamically stable end-point of quantum evaporation of the cosmological horizon. A source term in the Einstein equations connects smoothly two de Sitter vacua with different values of cosmological constant and corresponds to anisotropic vacuum dark fluid defined by symmetry of its stress-energy tensor which is invariant under the radial boosts. Global structure of space-time is the same as for the de Sitter space-time. Cosmological evolution goes from a big initial value of the cosmological constant towards its presently observed value.
NASA Astrophysics Data System (ADS)
Khitun, Alexander; Kozhevnikov, Alexander; Gertz, Frederick; Filimonov, Yuri
2015-03-01
Collective oscillation of spins in magnetic lattice known as spin waves (magnons) possess relatively long coherence length at room temperature, which makes it possible to build sub-micrometer scale holographic devices similar to the devices developed in optics. In this work, we present a prototype 2-bit magnonic holographic memory. The memory consists of the double-cross waveguide structure made of Y3Fe2(FeO4)3 with magnets placed on the top of waveguide junctions. Information is encoded in the orientation of the magnets, while the read-out is accomplished by the spin waves generated by the micro-antennas placed on the edges of the waveguides. The interference pattern produced by multiple spin waves makes it possible to build a unique holographic image of the magnetic structure and recognize the state of the each magnet. The development of magnonic holographic devices opens a new horizon for building scalable holographic devices compatible with conventional electronic devices. This work was supported in part by the FAME Center, one of six centers of STARnet, a Semiconductor Research Corporation program sponsored by MARCO and DARPA and by the National Science Foundation under the NEB2020 Grant ECCS-1124714.
On the Weyl and Ricci tensors of Generalized Robertson-Walker space-times
NASA Astrophysics Data System (ADS)
Mantica, Carlo Alberto; Molinari, Luca Guido
2016-10-01
We prove theorems about the Ricci and the Weyl tensors on Generalized Robertson-Walker space-times of dimension n ≥ 3. In particular, we show that the concircular vector introduced by Chen decomposes the Ricci tensor as a perfect fluid term plus a term linear in the contracted Weyl tensor. The Weyl tensor is harmonic if and only if it is annihilated by Chen's vector, and any of the two conditions is necessary and sufficient for the Generalized Robertson-Walker (GRW) space-time to be a quasi-Einstein (perfect fluid) manifold. Finally, the general structure of the Riemann tensor for Robertson-Walker space-times is given, in terms of Chen's vector. In n = 4, a GRW space-time with harmonic Weyl tensor is a Robertson-Walker space-time.
NASA Astrophysics Data System (ADS)
Beaulieu, Rene M.; Lessard, Roger A.; Bolte, Michel
1998-09-01
Photoinduced holographic surface relief gratings have been fabricate din dichromated poly(acrylic acid) films. These gratings are formed in darkness subsequent to the illumination at 442 nm and they are obtained without any chemical treatment or wet processing. The influence of chemical parameters, such as ammonium dichromate and dimethylformamide concentrations, on the holographic characteristics of these gratings have been investigated. Holographic characteristics of the recording medium such as diffraction efficiency as a function of exposure, ammonium dichromate and dimethylformamide concentrations, and spatial frequency are presented in this paper.
Ricci time in the Lemaître-Tolman model and the block universe
NASA Astrophysics Data System (ADS)
Elmahalawy, Yasser; Hellaby, Charles; Ellis, George F. R.
2015-10-01
It is common to think of our universe according to the "block universe" concept, which says that spacetime consists of many "stacked" three-surfaces, labelled by some kind of proper time, . Standard ideas do not distinguish past and future, but Ellis' "evolving block universe" tries to make a fundamental distinction. One proposal for this proper time is the proper time measured along the timelike Ricci eigenlines, starting from the big bang. This work investigates the shape of the "Ricci time" surfaces relative to the the null surfaces. We use the Lemaître-Tolman metric as our inhomogeneous spacetime model, and we find the necessary and sufficient conditions for these constant surfaces, , to be spacelike or timelike. Furthermore, we look at the effect of strong gravity domains by determining the location of timelike S regions relative to apparent horizons. We find that constant Ricci time surfaces are always spacelike near the big bang, while at late times (near the crunch or the extreme far future), they are only timelike under special circumstances. At intermediate times, timelike S regions are common unless the variation of the bang time is restricted. The regions where these surfaces become timelike are often adjacent to apparent horizons, but always outside them, and in particular timelike S regions do not occur inside the horizons of black-hole-like models.
Computer generated holographic microtags
Sweatt, William C.
1998-01-01
A microlithographic tag comprising an array of individual computer generated holographic patches having feature sizes between 250 and 75 nanometers. The tag is a composite hologram made up of the individual holographic patches and contains identifying information when read out with a laser of the proper wavelength and at the proper angles of probing and reading. The patches are fabricated in a steep angle Littrow readout geometry to maximize returns in the -1 diffracted order. The tags are useful as anti-counterfeiting markers because of the extreme difficulty in reproducing them.
Computer generated holographic microtags
Sweatt, W.C.
1998-03-17
A microlithographic tag comprising an array of individual computer generated holographic patches having feature sizes between 250 and 75 nanometers is disclosed. The tag is a composite hologram made up of the individual holographic patches and contains identifying information when read out with a laser of the proper wavelength and at the proper angles of probing and reading. The patches are fabricated in a steep angle Littrow readout geometry to maximize returns in the -1 diffracted order. The tags are useful as anti-counterfeiting markers because of the extreme difficulty in reproducing them. 5 figs.
1990-09-01
optical path from HOE to focal point can be made (ie same for both rays. We do this for a thin lens; in reality, the condition is obtained by ray...I2 RADC-TR-90-200 Final Technical Report September 1990 uric FILE COPY HOLOGRAPHIC OPTICAL HEAD Holometrix, Inc. P. Gregory DeBaryshe, Charles S. th...aa w 1. REPOA ATE 3. Reoa"rm AND DAS C September 1990 Final Aug 88 - May 90 4. TME AND hTME s. FUMO NUMBERS HOLOGRAPHIC OPTICAL HEAD C - F30602-88-C
Yi Piljin
2011-10-21
We overview a holographic QCD based on the D4-D8 string theory model, with emphasis on baryons and nucleon-meson interactions thereof. Baryons are realized as holographic images of Skyrmions, but with much qualitative changes. This allows us to derive, without adjustable parameters, couplings of baryons to the entire tower of spin one mesons and also to pseudoscalar mesons. We find some surprisingly good match against empirical values for nucleons, in particular. Tensor couplings to all axial-vectors and iso-singlet vectors all vanish, while, for {rho} mesons, tensor couplings are found to be dominant. We close with various cautionary comments and speculations.
Holographic renormalization and supersymmetry
NASA Astrophysics Data System (ADS)
Genolini, Pietro Benetti; Cassani, Davide; Martelli, Dario; Sparks, James
2017-02-01
Holographic renormalization is a systematic procedure for regulating divergences in observables in asymptotically locally AdS spacetimes. For dual boundary field theories which are supersymmetric it is natural to ask whether this defines a supersymmetric renormalization scheme. Recent results in localization have brought this question into sharp focus: rigid supersymmetry on a curved boundary requires specific geometric structures, and general arguments imply that BPS observables, such as the partition function, are invariant under certain deformations of these structures. One can then ask if the dual holographic observables are similarly invariant. We study this question in minimal N = 2 gauged supergravity in four and five dimensions. In four dimensions we show that holographic renormalization precisely reproduces the expected field theory results. In five dimensions we find that no choice of standard holographic counterterms is compatible with supersymmetry, which leads us to introduce novel finite boundary terms. For a class of solutions satisfying certain topological assumptions we provide some independent tests of these new boundary terms, in particular showing that they reproduce the expected VEVs of conserved charges.
NASA Technical Reports Server (NTRS)
Gange, Robert Allen (Inventor)
1977-01-01
A holographic recording medium comprising a conductive substrate, a photoconductive layer and an electrically alterable layer of a linear, low molecular weight hydrocarbon polymer has improved fatigue resistance. An acrylic barrier layer can be interposed between the photoconductive and electrically alterable layers.
Bao, Ning; Nezami, Sepehr; Ooguri, Hirosi; Stoica, Bogdan; Sully, James; Walter, Michael
2015-09-21
We initiate a systematic enumeration and classification of entropy inequalities satisfied by the Ryu-Takayanagi formula for conformal field theory states with smooth holographic dual geometries. For 2, 3, and 4 regions, we prove that the strong subadditivity and the monogamy of mutual information give the complete set of inequalities. This is in contrast to the situation for generic quantum systems, where a complete set of entropy inequalities is not known for 4 or more regions. We also find an infinite new family of inequalities applicable to 5 or more regions. The set of all holographic entropy inequalities bounds the phase space of Ryu-Takayanagi entropies, defining the holographic entropy cone. We characterize this entropy cone by reducing geometries to minimal graph models that encode the possible cutting and gluing relations of minimal surfaces. We find that, for a fixed number of regions, there are only finitely many independent entropy inequalities. To establish new holographic entropy inequalities, we introduce a combinatorial proof technique that may also be of independent interest in Riemannian geometry and graph theory.
Bao, Ning; Nezami, Sepehr; Ooguri, Hirosi; ...
2015-09-21
We initiate a systematic enumeration and classification of entropy inequalities satisfied by the Ryu-Takayanagi formula for conformal field theory states with smooth holographic dual geometries. For 2, 3, and 4 regions, we prove that the strong subadditivity and the monogamy of mutual information give the complete set of inequalities. This is in contrast to the situation for generic quantum systems, where a complete set of entropy inequalities is not known for 4 or more regions. We also find an infinite new family of inequalities applicable to 5 or more regions. The set of all holographic entropy inequalities bounds the phasemore » space of Ryu-Takayanagi entropies, defining the holographic entropy cone. We characterize this entropy cone by reducing geometries to minimal graph models that encode the possible cutting and gluing relations of minimal surfaces. We find that, for a fixed number of regions, there are only finitely many independent entropy inequalities. To establish new holographic entropy inequalities, we introduce a combinatorial proof technique that may also be of independent interest in Riemannian geometry and graph theory.« less
Holographic elements and holographic techniques used in photonics
NASA Astrophysics Data System (ADS)
Heidt, Gerald L.; Speer, Dominic
2013-03-01
Since the invention of holography in 1948, most of the attention has been focused on holographic 3 dimensional images and displays. This new 3D technology generated a lot of attention in the 70's through the 90's. The work that was being done for manipulating light other than 3D imaging and displays was not as well known. This paper discusses how holographic elements and holographic interference techniques are now being used in the Photonics industry.
Probing gravitation, dark energy, and acceleration
Linder, Eric V.
2004-02-20
The acceleration of the expansion of the universe arises from unknown physical processes involving either new fields in high energy physics or modifications of gravitation theory. It is crucial for our understanding to characterize the properties of the dark energy or gravity through cosmological observations and compare and distinguish between them. In fact, close consistencies exist between a dark energy equation of state function w(z) and changes to the framework of the Friedmann cosmological equations as well as direct spacetime geometry quantities involving the acceleration, such as ''geometric dark energy'' from the Ricci scalar. We investigate these interrelationships, including for the case of super acceleration or phantom energy where the fate of the universe may be more gentle than the Big Rip.
Simplest holographic technique: unsurpassed features very friendly to practical applications
NASA Astrophysics Data System (ADS)
Petrov, Valery
1996-12-01
Holography and holographic interferometry in spite of their attractive features are rather rarely used for industrial inspections of products and components or in medical practice due to relative complexity, costs, lengthy multi- stage procedures, need of dark rooms and vibration insulation. But the most of these drawbacks might be avoided if momental holography on silver halide (SH) media is involved. Momental technique simplifies drastically the holographic process and ensures quasi real time or real time (in situ) bright reconstructions from holograms, real time or double exposure holographic interferograms. This technique permits the user to avoid dark rooms and to work with standard office or industrial illumination of 0.5 klx or even much more. Moreover, very bright holograms and holographic interferograms might be obtained also in the street in a diffused daylight or even under strong direct sunlight illumination. High quality off-axis and reflection holograms, interferograms, HOE were obtained utilizing ruby, semiconductor, He-Ne and Ar laser sources. Agfa-Gevaert 8 E 75 HD films and plates, Russian PFG-03 and PFG-03 C (color) plates were used as recording media. Different levels of external polychromatic illumination were applied to holograms and holographic interferograms during production. Extremely high levels (more than 50 klx) were also tested. Bright holographic reconstructions were obtained even in such unpromising environment. Photographic images from such holograms are presented. One of the holograms was momentally photoprocessed in the light of projector (a few klx) during presentation of this paper at the conference 'Holographic and Diffractive Techniques' in Berlin. Another unique feature of the technique: extremely long-term storage of holographic data on SH media in latent form is shown. It relates both to holograms recorded with cw lasers and to those recorded with pulsed laser sources. The latter case is the most interesting because it was
Intelligent holographic databases
NASA Astrophysics Data System (ADS)
Barbastathis, George
Memory is a key component of intelligence. In the human brain, physical structure and functionality jointly provide diverse memory modalities at multiple time scales. How could we engineer artificial memories with similar faculties? In this thesis, we attack both hardware and algorithmic aspects of this problem. A good part is devoted to holographic memory architectures, because they meet high capacity and parallelism requirements. We develop and fully characterize shift multiplexing, a novel storage method that simplifies disk head design for holographic disks. We develop and optimize the design of compact refreshable holographic random access memories, showing several ways that 1 Tbit can be stored holographically in volume less than 1 m3, with surface density more than 20 times higher than conventional silicon DRAM integrated circuits. To address the issue of photorefractive volatility, we further develop the two-lambda (dual wavelength) method for shift multiplexing, and combine electrical fixing with angle multiplexing to demonstrate 1,000 multiplexed fixed holograms. Finally, we propose a noise model and an information theoretic metric to optimize the imaging system of a holographic memory, in terms of storage density and error rate. Motivated by the problem of interfacing sensors and memories to a complex system with limited computational resources, we construct a computer game of Desert Survival, built as a high-dimensional non-stationary virtual environment in a competitive setting. The efficacy of episodic learning, implemented as a reinforced Nearest Neighbor scheme, and the probability of winning against a control opponent improve significantly by concentrating the algorithmic effort to the virtual desert neighborhood that emerges as most significant at any time. The generalized computational model combines the autonomous neural network and von Neumann paradigms through a compact, dynamic central representation, which contains the most salient features
Lohmann, A W; Sauer, F
1988-07-15
A typical job in optical computing is to illuminate an array of small nonlinear optical components, separated by wide gaps to avoid crosstalk. We do this by letting a wide uniform beam fall onto a densely packed array of minifying telescopes. Each telescope produces a narrow bundle of parallel rays which illuminates one of the nonlinear optical components. The holographic telescopes can do more than change the width of the bundles of parallel rays. Their image forming capability allows the transmission of many pixels per channel in parallel. The pair of lenslets of a single holographic telescope (Kepler or Galilean) is produced in rigid coupling. The monolithic production avoids adjusting the two lenslets later on.
Deriving covariant holographic entanglement
NASA Astrophysics Data System (ADS)
Dong, Xi; Lewkowycz, Aitor; Rangamani, Mukund
2016-11-01
We provide a gravitational argument in favour of the covariant holographic entanglement entropy proposal. In general time-dependent states, the proposal asserts that the entanglement entropy of a region in the boundary field theory is given by a quarter of the area of a bulk extremal surface in Planck units. The main element of our discussion is an implementation of an appropriate Schwinger-Keldysh contour to obtain the reduced density matrix (and its powers) of a given region, as is relevant for the replica construction. We map this contour into the bulk gravitational theory, and argue that the saddle point solutions of these replica geometries lead to a consistent prescription for computing the field theory Rényi entropies. In the limiting case where the replica index is taken to unity, a local analysis suffices to show that these saddles lead to the extremal surfaces of interest. We also comment on various properties of holographic entanglement that follow from this construction.
Holographic Optical Coherence Imaging
NASA Astrophysics Data System (ADS)
Nolte, David D.; Jeong, Kwan; Turek, John; French, Paul M. W.
This chapter gives an overview of the principles of holographic OCI. It begins with a description of off-axis holography as spatial heterodyne detection and continues with the origin and role of speckle in multichannel illumination of tissue. Image-domain holography (IDH) and Fourier-domain holography (FDH) are described. Holography in the Fourier domain has the capability for phase-contrast imaging that can acquire small sub-wavelength displacements despite long coherence length. The trade-offs between photorefractive and digital holography are discussed. The chief biological target is multicellular spheroids, specifically rat osteogenic sarcomas that are grown in vitro. After describing the physiological and optical properties of these spheroids, results from holographic OCI are presented using both photorefractive and digital holography.
Holographic Optical Data Storage
NASA Technical Reports Server (NTRS)
Timucin, Dogan A.; Downie, John D.; Norvig, Peter (Technical Monitor)
2000-01-01
Although the basic idea may be traced back to the earlier X-ray diffraction studies of Sir W. L. Bragg, the holographic method as we know it was invented by D. Gabor in 1948 as a two-step lensless imaging technique to enhance the resolution of electron microscopy, for which he received the 1971 Nobel Prize in physics. The distinctive feature of holography is the recording of the object phase variations that carry the depth information, which is lost in conventional photography where only the intensity (= squared amplitude) distribution of an object is captured. Since all photosensitive media necessarily respond to the intensity incident upon them, an ingenious way had to be found to convert object phase into intensity variations, and Gabor achieved this by introducing a coherent reference wave along with the object wave during exposure. Gabor's in-line recording scheme, however, required the object in question to be largely transmissive, and could provide only marginal image quality due to unwanted terms simultaneously reconstructed along with the desired wavefront. Further handicapped by the lack of a strong coherent light source, optical holography thus seemed fated to remain just another scientific curiosity, until the field was revolutionized in the early 1960s by some major breakthroughs: the proposition and demonstration of the laser principle, the introduction of off-axis holography, and the invention of volume holography. Consequently, the remainder of that decade saw an exponential growth in research on theory, practice, and applications of holography. Today, holography not only boasts a wide variety of scientific and technical applications (e.g., holographic interferometry for strain, vibration, and flow analysis, microscopy and high-resolution imagery, imaging through distorting media, optical interconnects, holographic optical elements, optical neural networks, three-dimensional displays, data storage, etc.), but has become a prominent am advertising
NASA Astrophysics Data System (ADS)
Nawa, Kanabu; Suganuma, Hideo; Kojo, Toru
2007-04-01
We study baryons in holographic QCD with D4/D8/D8¯ multi-D-brane system. In holographic QCD, the baryon appears as a topologically nontrivial chiral soliton in a four-dimensional effective theory of mesons. We call this topological soliton brane-induced Skyrmion. Some review of D4/D8/D8¯ holographic QCD is presented from the viewpoints of recent hadron physics and QCD phenomenologies. A four-dimensional effective theory with pions and ρ mesons is uniquely derived from the non-Abelian Dirac-Born-Infeld (DBI) action of D8 brane with D4 supergravity background at the leading order of large Nc, without small amplitude expansion of meson fields to discuss chiral solitons. For the hedgehog configuration of pion and ρ-meson fields, we derive the energy functional and the Euler-Lagrange equation of brane-induced Skyrmion from the meson effective action induced by holographic QCD. Performing the numerical calculation, we obtain the soliton solution and figure out the pion profile F(r) and the ρ-meson profile G˜(r) of the brane-induced Skyrmion with its total energy, energy density distribution, and root-mean-square radius. These results are compared with the experimental quantities of baryons and also with the profiles of standard Skyrmion without ρ mesons. We analyze interaction terms of pions and ρ mesons in brane-induced Skyrmion, and find a significant ρ-meson component appearing in the core region of a baryon.
Nawa, Kanabu; Suganuma, Hideo; Kojo, Toru
2007-04-15
We study baryons in holographic QCD with D4/D8/D8 multi-D-brane system. In holographic QCD, the baryon appears as a topologically nontrivial chiral soliton in a four-dimensional effective theory of mesons. We call this topological soliton brane-induced Skyrmion. Some review of D4/D8/D8 holographic QCD is presented from the viewpoints of recent hadron physics and QCD phenomenologies. A four-dimensional effective theory with pions and {rho} mesons is uniquely derived from the non-Abelian Dirac-Born-Infeld (DBI) action of D8 brane with D4 supergravity background at the leading order of large N{sub c}, without small amplitude expansion of meson fields to discuss chiral solitons. For the hedgehog configuration of pion and {rho}-meson fields, we derive the energy functional and the Euler-Lagrange equation of brane-induced Skyrmion from the meson effective action induced by holographic QCD. Performing the numerical calculation, we obtain the soliton solution and figure out the pion profile F(r) and the {rho}-meson profile G-tilde(r) of the brane-induced Skyrmion with its total energy, energy density distribution, and root-mean-square radius. These results are compared with the experimental quantities of baryons and also with the profiles of standard Skyrmion without {rho} mesons. We analyze interaction terms of pions and {rho} mesons in brane-induced Skyrmion, and find a significant {rho}-meson component appearing in the core region of a baryon.
Holographic phase transition in a noncritical holographic model
Cui Shengliang; Gao Yihong; Xu Weishui
2010-01-15
We consider a holographic model constructed from the intersecting brane configuration D4-D4/D4 in noncritical string theory. We study the chiral phase diagram of this holographic QCD-like model with a finite baryon chemical potential through the supergravity dual approximation.
Method and apparatus for holographic wavefront diagnostics
Toeppen, J.S.
1995-04-25
A wavefront diagnostic apparatus has an optic and a measuring system. The optic forms a holographic image in response to a beam of light striking a hologram formed on a surface of the optic. The measuring system detects the position of the array of holographic images and compares the positions of the array of holographic images to a reference holographic image. 3 figs.
Method and apparatus for holographic wavefront diagnostics
Toeppen, John S.
1995-01-01
A wavefront diagnostic apparatus has an optic and a measuring system. The optic forms a holographic image in response to a beam of light striking a hologram formed on a surface of the optic. The measuring system detects the position of the array of holographic images and compares the positions of the array of holographic images to a reference holographic image.
Ricci curvature: An economic indicator for market fragility and systemic risk.
Sandhu, Romeil S; Georgiou, Tryphon T; Tannenbaum, Allen R
2016-05-01
Quantifying the systemic risk and fragility of financial systems is of vital importance in analyzing market efficiency, deciding on portfolio allocation, and containing financial contagions. At a high level, financial systems may be represented as weighted graphs that characterize the complex web of interacting agents and information flow (for example, debt, stock returns, and shareholder ownership). Such a representation often turns out to provide keen insights. We show that fragility is a system-level characteristic of "business-as-usual" market behavior and that financial crashes are invariably preceded by system-level changes in robustness. This was done by leveraging previous work, which suggests that Ricci curvature, a key geometric feature of a given network, is negatively correlated to increases in network fragility. To illustrate this insight, we examine daily returns from a set of stocks comprising the Standard and Poor's 500 (S&P 500) over a 15-year span to highlight the fact that corresponding changes in Ricci curvature constitute a financial "crash hallmark." This work lays the foundation of understanding how to design (banking) systems and policy regulations in a manner that can combat financial instabilities exposed during the 2007-2008 crisis.
Ricci curvature: An economic indicator for market fragility and systemic risk
Sandhu, Romeil S.; Georgiou, Tryphon T.; Tannenbaum, Allen R.
2016-01-01
Quantifying the systemic risk and fragility of financial systems is of vital importance in analyzing market efficiency, deciding on portfolio allocation, and containing financial contagions. At a high level, financial systems may be represented as weighted graphs that characterize the complex web of interacting agents and information flow (for example, debt, stock returns, and shareholder ownership). Such a representation often turns out to provide keen insights. We show that fragility is a system-level characteristic of “business-as-usual” market behavior and that financial crashes are invariably preceded by system-level changes in robustness. This was done by leveraging previous work, which suggests that Ricci curvature, a key geometric feature of a given network, is negatively correlated to increases in network fragility. To illustrate this insight, we examine daily returns from a set of stocks comprising the Standard and Poor’s 500 (S&P 500) over a 15-year span to highlight the fact that corresponding changes in Ricci curvature constitute a financial “crash hallmark.” This work lays the foundation of understanding how to design (banking) systems and policy regulations in a manner that can combat financial instabilities exposed during the 2007–2008 crisis. PMID:27386522
Robust holographic storage system design.
Watanabe, Takahiro; Watanabe, Minoru
2011-11-21
Demand is increasing daily for large data storage systems that are useful for applications in spacecraft, space satellites, and space robots, which are all exposed to radiation-rich space environment. As candidates for use in space embedded systems, holographic storage systems are promising because they can easily provided the demanded large-storage capability. Particularly, holographic storage systems, which have no rotation mechanism, are demanded because they are virtually maintenance-free. Although a holographic memory itself is an extremely robust device even in a space radiation environment, its associated lasers and drive circuit devices are vulnerable. Such vulnerabilities sometimes engendered severe problems that prevent reading of all contents of the holographic memory, which is a turn-off failure mode of a laser array. This paper therefore presents a proposal for a recovery method for the turn-off failure mode of a laser array on a holographic storage system, and describes results of an experimental demonstration.
Holographic Baryons and Instanton Crystal
NASA Astrophysics Data System (ADS)
Kaplunovsky, Vadim; Melnikov, Dmitry; Sonnenschein, Jacob
In a wide class of holographic models, like the one proposed by Sakai and Sugimoto, baryons can be approximated by instantons of non-abelian gauge fields that live on the world-volume of flavor D-branes. In the leading order, those are just the Yang-Mills instantons, whose solutions can be constructed from the celebrated ADHM construction. This fact can be used to study various properties of baryons in the holographic limit. In particular, one can attempt to construct a holographic description of the cold dense nuclear matter phase of baryons. It can be argued that holographic baryons in such a regime are necessarily in a solid crystalline phase. In this review we summarize the known results on the construction and phases of crystals of the holographic baryons.
Archiving Saudi heritage using the holographic medium
NASA Astrophysics Data System (ADS)
Althagafi, A.; Richardson, M.
2015-03-01
This paper focuses on the use of the Yuri Nikolaevich DENISYUK holographic recording process to document, archive and display Saudi heritage. The goal of this research is to develop a technique of archiving heritage by using a high-tech holographic process to capture a three-dimensional presentation of ancient jewelry artifacts of the Saudi Heritage in particular. This study concentrates on five particular items of handmade authentic ancient metal jewelry from different parts of Saudi Arabia. When conducting this research experiments were conducted using both red-green sensitive plates sensitive to 633 nm and 532 nm respectively. Material thickness ranged between 1.5 and 3 millimeters were used, consequently in the dark room, varied chemicals for developing the holograms were employed. Red and green laser devices were also used with exposure times between 8 to 18 seconds of laser light dispersion through diffused surfaces in reflection holography. The outcome in each case was varied. The holograms captured the jewelry pieces with all the engravings and minute details, thus archiving the Saudi Heritage of that time. What makes holograms a revolutionary method for presenting valuable and/or ancient artifacts is the fact that they offer a more practical and convenient solution to travel around the world than displaying the originals items. Thus, museum visitors can enjoy and appreciate the precious artifacts otherwise unseen and lost without holography.
Probing gravitational dark matter
Ren, Jing; He, Hong-Jian
2015-03-27
So far all evidences of dark matter (DM) come from astrophysical and cosmological observations, due to the gravitational interactions of DM. It is possible that the true DM particle in the universe joins gravitational interactions only, but nothing else. Such a Gravitational DM (GDM) may act as a weakly interacting massive particle (WIMP), which is conceptually simple and attractive. In this work, we explore this direction by constructing the simplest scalar GDM particle χ{sub s}. It is a ℤ{sub 2} odd singlet under the standard model (SM) gauge group, and naturally joins the unique dimension-4 interaction with Ricci curvature, ξ{sub s}χ{sub s}{sup 2}R, where ξ{sub s} is the dimensionless nonminimal coupling. We demonstrate that this gravitational interaction ξ{sub s}χ{sub s}{sup 2}R, together with Higgs-curvature nonminimal coupling term ξ{sub h}H{sup †}HR, induces effective couplings between χ{sub s}{sup 2} and SM fields, and can account for the observed DM thermal relic abundance. We analyze the annihilation cross sections of GDM particles and derive the viable parameter space for realizing the DM thermal relic density. We further study the direct/indirect detections and the collider signatures of such a scalar GDM. These turn out to be highly predictive and testable.
Holographic charge oscillations
NASA Astrophysics Data System (ADS)
Blake, Mike; Donos, Aristomenis; Tong, David
2015-04-01
The Reissner-Nordström black hole provides the prototypical description of a holographic system at finite density. We study the response of this system to the presence of a local, charged impurity. Below a critical temperature, the induced charge density, which screens the impurity, exhibits oscillations. These oscillations can be traced to the singularities in the density-density correlation function moving in the complex momentum plane. At finite temperature, the oscillations are very similar to the Friedel oscillations seen in Fermi liquids. However, at zero temperature the oscillations in the black hole background remain exponentially damped, while Friedel oscillations relax to a power-law.
Holographic Model of Hadronization
Evans, Nick; Tedder, Andrew
2008-04-25
We study hadronization of the final state in a particle-antiparticle annihilation using a holographic gravity dual description of QCD. At the point of hadronization we match the events to a simple (Gaussian) energy distribution in the five dimensional theory. The final state multiplicities are then modeled by calculating the overlap between the Gaussian and a set of functions in the fifth dimension which represent each hadron. We compare our results to those measured in e{sup +}e{sup -} collisions. Hadron production numbers over a range of 4 orders of magnitude are reproduced well.
Holographic model of hadronization.
Evans, Nick; Tedder, Andrew
2008-04-25
We study hadronization of the final state in a particle-antiparticle annihilation using a holographic gravity dual description of QCD. At the point of hadronization we match the events to a simple (Gaussian) energy distribution in the five dimensional theory. The final state multiplicities are then modeled by calculating the overlap between the Gaussian and a set of functions in the fifth dimension which represent each hadron. We compare our results to those measured in e(+)e(-) collisions. Hadron production numbers over a range of 4 orders of magnitude are reproduced well.
Biopolymer holographic diffraction gratings
NASA Astrophysics Data System (ADS)
Savić Šević, Svetlana; Pantelić, Dejan
2008-03-01
Surface-relief diffraction gratings are holographically recorded in dextran sensitized with ammonium dichromate (DCD). DCD was exposed with single-frequency 200 mW diode pumped ND-YAG laser, at 532 nm. The diffraction grating profiles were analyzed by atomic force microscopy (AFM). It was found that different surface profiles could be obtained. Gratings with 330 lines/mm spatial frequencies were made. Existence of higher harmonics in Fourier Transform of non-sinusoidal profiles shows that DCD is capable of recording spatial frequencies up to 1320 lines/mm (four times fundamental frequency). The measured maximum relief depth of the DCD grating is 402 nm.
Holographic charge density waves
NASA Astrophysics Data System (ADS)
Donos, Aristomenis; Gauntlett, Jerome P.
2013-06-01
We show that strongly coupled holographic matter at finite charge density can exhibit charge density wave phases which spontaneously break translation invariance while preserving time-reversal and parity invariance. We show that such phases are possible within Einstein-Maxwell-dilaton theory in general spacetime dimensions. We also discuss related spatially modulated phases when there is an additional coupling to a second vector field, possibly with nonzero mass. We discuss how these constructions, and others, should be associated with novel spatially modulated ground states.
Laser adaptive holographic hydrophone
Romashko, R V; Kulchin, Yu N; Bezruk, M N; Ermolaev, S A
2016-03-31
A new type of a laser hydrophone based on dynamic holograms, formed in a photorefractive crystal, is proposed and studied. It is shown that the use of dynamic holograms makes it unnecessary to use complex optical schemes and systems for electronic stabilisation of the interferometer operating point. This essentially simplifies the scheme of the laser hydrophone preserving its high sensitivity, which offers the possibility to use it under a strong variation of the environment parameters. The laser adaptive holographic hydrophone implemented at present possesses the sensitivity at a level of 3.3 mV Pa{sup -1} in the frequency range from 1 to 30 kHz. (laser hydrophones)
Holographic magnetic phase transition
Lifschytz, Gilad; Lippert, Matthew
2009-09-15
We study four-dimensional interacting fermions in a strong magnetic field, using the holographic Sakai-Sugimoto model of intersecting D4- and D8-branes in the deconfined, chiral-symmetric parallel phase. We find that as the magnetic field is varied, while staying in the parallel phase, the fermions exhibit a first-order phase transition in which their magnetization jumps discontinuously. Properties of this transition are consistent with a picture in which some of the fermions jump to the lowest Landau level. Similarities to known magnetic phase transitions are discussed.
Cosmology of a holographic induced gravity model with curvature effects
Bouhmadi-Lopez, Mariam; Errahmani, Ahmed; Ouali, Taoufiq
2011-10-15
We present a holographic model of the Dvali-Gabadadze-Porrati scenario with a Gauss-Bonnet term in the bulk. We concentrate on the solution that generalizes the normal Dvali-Gabadadze-Porrati branch. It is well known that this branch cannot describe the late-time acceleration of the universe even with the inclusion of a Gauss-Bonnet term. Here, we show that this branch in the presence of a Gauss-Bonnet curvature effect and a holographic dark energy with the Hubble scale as the infrared cutoff can describe the late-time acceleration of the universe. It is worthwhile to stress that such an energy density component cannot do the same job on the normal Dvali-Gabadadze-Porrati branch (without Gauss-Bonnet modifications) nor in a standard four-dimensional relativistic model. The acceleration on the brane is also presented as being induced through an effective dark energy which corresponds to a balance between the holographic one and geometrical effects encoded through the Hubble parameter.
A wideband sensitive holographic photopolymer
NASA Astrophysics Data System (ADS)
Huang, Mingju; Wang, Sulian; Wang, Airong; Gong, Qiaoxia; Gan, Fuxi
2005-05-01
A novel wideband sensitive dry holographic photopolymer sensitized by rose bengal (RB) and methylene blue (MB) is fabricated, the holographic storage characteristics of which are investigated under different exposure wavelengths. The result shows that the sensitive spectral band exceeds 200 nm in visible light range, the maximum diffraction efficiency under different exposure wavelengths is more than 40% and decreases with the decrease of exposure wavelength, the exposure sensitivity is not change with the exposure wavelength. This photopolymer is appropriate for wavelength multiplexing or multi-wavelength recording in digital holographic storage.
Conically scanned holographic lidar telescope
NASA Technical Reports Server (NTRS)
Schwemmer, Geary (Inventor)
1993-01-01
An optical scanning device utilizing a source of optical energy such as laser light backscattered from the earth's atmosphere or transmitted outward as in a lidar, a rotating holographic optical element having an axis of rotation perpendicular to the plane of its substrate, and having a stationary focus which may or may not be located on its axis of rotation, with the holographic optical element diffracting the source of optical energy at an angle to its rotation axis enabling a conical scanning area and a motor for supporting and rotating the rotating holographic optical element, is described.
Engineering holographic graphene
Semenoff, Gordon W.
2012-09-24
We present a top-down string theory holographic model of strongly interacting relativistic 2 + 1-dimensional fermions, paying careful attention to the discrete symmetries of parity and time reversal invariance. Our construction is based on probe D7-branes in AdS{sub 5} Multiplication-Sign S{sup 5}, stabilized by internal fluxes. We find three solutions, a parity and time reversal invariant conformal field theory which can be viewed as a particular deformation of Coulomb interacting graphene, a parity and time reversal violating but gapless field theory and a system with a parity and time reversal violating charge gap. We show that the Chern-Simons-like electric response function, which is generated perturbatively at one-loop order by parity violating fermions and which is protected by a no-renormalization theorem at orders beyond one loop, indeed appears with the correctly quantized coefficient in the charge gapped theory. In the gapless parity violating solution, the Chern-Simons response function obtains quantum corrections which we compute in the holographic theory.
Holographic interferometry with the compact arrowhead holographic setup.
Ladera, Celso L
2010-05-15
A symmetric off-axis holographic setup, shaped as an arrowhead, which requires neither a collimator nor a beam splitter, is presented. It is applied to measure small perpendicular-to-surface displacements and deformations and the magnetostriction of a body by holographic interferometry. It offers advantages such as implicit fulfilment of several hologram recording conditions, possible use of short coherence length light sources, low-cost, and significant immunity against mechanical perturbations.
Bose-Einstein condensation on a manifold with non-negative Ricci curvature
Akant, Levent Ertuğrul, Emine Tapramaz, Ferzan Turgut, O. Teoman
2015-01-15
The Bose-Einstein condensation for an ideal Bose gas and for a dilute weakly interacting Bose gas in a manifold with non-negative Ricci curvature is investigated using the heat kernel and eigenvalue estimates of the Laplace operator. The main focus is on the nonrelativistic gas. However, special relativistic ideal gas is also discussed. The thermodynamic limit of the heat kernel and eigenvalue estimates is taken and the results are used to derive bounds for the depletion coefficient. In the case of a weakly interacting gas, Bogoliubov approximation is employed. The ground state is analyzed using heat kernel methods and finite size effects on the ground state energy are proposed. The justification of the c-number substitution on a manifold is given.
Nonholonomic jet deformations, exact solutions for modified Ricci soliton and Einstein equations
NASA Astrophysics Data System (ADS)
Rajpoot, Subhash; Vacaru, Sergiu I.
Let g be a pseudo-Riemannian metric of arbitrary signature on a manifold V with conventional n + n-dimensional splitting, n ≥ 2, determined by a nonholonomic (nonintegrable) distribution 𝒩 defining a generalized (nonlinear) connection and associated nonholonomic frame structures. We work with an adapted linear metric compatible connection D ̂ and its nonzero torsion 𝒯 ̂, both completely determined by g. Our first goal is to prove that there are certain generalized frame and/or jet transforms and prolongations with (g,V) → (g ̂,V ̂) into explicit classes of solutions of some generalized Einstein equations R ̂ic = Λg ̂, Λ = const, encoding various types of (nonholonomic) Ricci soliton configurations and/or jet variables and symmetries. The second goal is to solve additional constraint equations for zero torsion, 𝒯 ̂ = 0, on generalized solutions constructed in explicit forms with jet variables and extract Levi-Civita configurations. This allows us to find generic off-diagonal exact solutions depending on all space time coordinates on V via generating and integration functions and various classes of constant jet parameters and associated symmetries. Our third goal is to study how such generalized metrics and connections can be related by the so-called “half-conformal” and/or jet deformations of certain subclasses of solutions with one, or two, Killing symmetries. Finally, we present some examples of exact solutions constructed as nonholonomic jet prolongations of the Kerr metrics, with possible Ricci soliton deformations, and characterized by nonholonomic jet structures and generalized connections.
Adventures in holographic dimer models
NASA Astrophysics Data System (ADS)
Kachru, Shamit; Karch, Andreas; Yaida, Sho
2011-03-01
We abstract the essential features of holographic dimer models, and develop several new applications of these models. Firstly, semi-holographically coupling free band fermions to holographic dimers, we uncover novel phase transitions between conventional Fermi liquids and non-Fermi liquids, accompanied by a change in the structure of the Fermi surface. Secondly, we make dimer vibrations propagate through the whole crystal by way of double trace deformations, obtaining nontrivial band structure. In a simple toy model, the topology of the band structure experiences an interesting reorganization as we vary the strength of the double trace deformations. Finally, we develop tools that would allow one to build, in a bottom-up fashion, a holographic avatar of the Hubbard model.
Hyperspectral holographic Fourier-microscopy
Kalenkov, G S; Kalenkov, S G; Shtan'ko, A E
2015-04-30
A detailed theory of the method of holographic recording of hyperspectral wave fields is developed. New experimentally obtained hyperspectral holographic images of microscopic objects are presented. The possibilities of the method are demonstrated experimentally using the examples of urgent microscopy problems: speckle noise suppression, obtaining hyperspectral image of a microscopic object, as well as synthesis of a colour image and obtaining an optical profile of a phase object. (holography)
Combined Holographic Infrared Inspection Instrumentation
1989-12-01
wavefronts, an object beam and a refererce beam, cn a suitable recording material, such as a photog"".phic film . V, hen properly illuminated by the...methods for fringe control 14 and improved methods for processing holograms in place using better film methods and/or thermoplastic recording techniques...Inc. Holomatic 8000 phased-locked holographic interferometry system. The Holomatic 8000 records the reference hologram on 35mm holographic film which is
Finite Inflation, Holography, and Dark Matter Annihilation
NASA Astrophysics Data System (ADS)
Scacco, Andrew Joseph
This thesis covers work on theoretical cosmology relating to inflation, de Sitter space, dark matter annihilation, and holography. A unifying feature of all these topics is that all of them occur in de Sitter space or focus on epochs of the Universe when the spacetime was close to de Sitter and that all of them have some connection to holography. Chapter 1 provides a pedagogical introduction to the fundamentals of cosmology, inflation, de Sitter space, dark matter annihilation and entanglement entropy. Chapter 2 covers the impact on the causal entropic principle of dark matter annihilation that we find to have the greatest relevance at late times in the future when the dark energy has driven the universe to be asymptotically de Sitter. In this chapter we estimate holographically preferred dark matter properties for a range of assumptions. Chapter 3 covers holographic bounds in models of finite inflation, specifically the Banks-Fischler bound and de Sitter equilibrium. The assumptions in each of these models are explored in detail and some interesting new connections are presented. Chapter 4 tests models of inflation with a fast-roll start that happen to satisfy the holographic bounds in Chapter 3 against cosmic microwave background data from Planck. We find a slight preference for a feature at the scale predicted by the Banks-Fischler bound though this preference is not found to be statistically significant. Chapter 5 contains a numerical computation of the holographic mutual information for an annular configuration of regions on a conformal field theory in de Sitter space using the AdS/CFT correspondence. This computation shows that the de Sitter space CFT entanglement entropy matches what would be expected from a Minkowski CFT and shows that the HRT conjecture works for this case.
Segmented holographic spectrum splitting concentrator
NASA Astrophysics Data System (ADS)
Ayala, Silvana P.; Vorndran, Shelby; Wu, Yuechen; Chrysler, Benjamin; Kostuk, Raymond K.
2016-09-01
This paper presents a segmented parabolic concentrator employing holographic spectral filters that provide focusing and spectral bandwidth separation capability to the system. Strips of low band gap silicon photovoltaic (PV) cells are formed into a parabolic surface as shown by Holman et. al. [1]. The surface of the PV segments is covered with holographic elements formed in dichromated gelatin. The holographic elements are designed to transmit longer wavelengths to silicon cells, and to reflect short wavelength light towards a secondary collector where high-bandgap PV cells are mounted. The system can be optimized for different combinations of diffuse and direct solar illumination conditions for particular geographical locations by controlling the concentration ratio and filtering properties of the holographic elements. In addition, the reflectivity of the back contact of the silicon cells is used to increase the optical path length and light trapping. This potentially allows the use of thin film silicon for the low bandgap PV cell material. The optical design combines the focusing properties of the parabolic concentrator and the holographic element to control the concentration ratio and uniformity of the spectral distribution at the high bandgap cell location. The presentation concludes with a comparison of different spectrum splitting holographic filter materials for this application.
Losing forward momentum holographically
NASA Astrophysics Data System (ADS)
Balasubramanian, Koushik; Herzog, Christopher P.
2014-06-01
We present a numerical scheme for solving Einstein’s Equations in the presence of a negative cosmological constant and an event horizon with planar topology. Our scheme allows for the introduction of a particular metric source at the conformal boundary. Such a spacetime has a dual holographic description in terms of a strongly interacting quantum field theory at nonzero temperature. By introducing a sinusoidal static metric source that breaks translation invariance, we study momentum relaxation in the field theory. In the long wavelength limit, our results are consistent with the fluid-gravity correspondence and relativistic hydrodynamics. In the small amplitude limit, our results are consistent with the memory function prediction for the momentum relaxation rate. Our numerical scheme allows us to study momentum relaxation outside these two limits as well.
Striped holographic superconductor
Flauger, Raphael; Pajer, Enrico; Papanikolaou, Stefanos
2011-03-15
We study inhomogeneous solutions of a 3+1-dimensional Einstein-Maxwell-scalar theory. Our results provide a holographic model of superconductivity in the presence of a charge density wave sourced by a modulated chemical potential. We find that below a critical temperature T{sub c} superconducting stripes develop. We show that they are thermodynamically favored over the normal state by computing the grand canonical potential. We investigate the dependence of T{sub c} on the modulation's wave vector, which characterizes the inhomogeneity. We find that it is qualitatively similar to that expected for a weakly coupled Bardeen-Cooper-Schrieer theory, but we point out a quantitative difference. Finally, we use our solutions to compute the conductivity along the direction of the stripes.
NASA Astrophysics Data System (ADS)
Johnson, Clifford V.
2014-10-01
It is shown that in theories of gravity where the cosmological constant is considered a thermodynamic variable, it is natural to use black holes as heat engines. Two examples are presented in detail using AdS charged black holes as the working substance. We notice that for static black holes, the maximally efficient traditional Carnot engine is also a Stirling engine. The case of negative cosmological constant supplies a natural realization of these engines in terms of the field theory description of the fluids to which they are holographically dual. We first propose a precise picture of how the traditional thermodynamic dictionary of holography is extended when the cosmological constant is dynamical and then conjecture that the engine cycles can be performed by using renormalization group flow. We speculate about the existence of a natural dual field theory counterpart to the gravitational thermodynamic volume.
Holographic Vortex Coronagraph
NASA Technical Reports Server (NTRS)
Palacios, David
2010-01-01
A holographic vortex coronagraph (HVC) has been proposed as an improvement over conventional coronagraphs for use in high-contrast astronomical imaging for detecting planets, dust disks, and other broadband light scatterers in the vicinities of stars other than the Sun. Because such light scatterers are so faint relative to their parent stars, in order to be able to detect them, it is necessary to effect ultra-high-contrast (typically by a factor of the order of 1010) suppression of broadband light from the stars. Unfortunately, the performances of conventional coronagraphs are limited by low throughput, dispersion, and difficulty of satisfying challenging manufacturing requirements. The HVC concept offers the potential to overcome these limitations.
Stability of holographic superconductors
Kanno, Sugumi; Soda, Jiro
2010-10-15
We study the dynamical stability of holographic superconductors. We first classify perturbations around black hole background solutions into vector and scalar sectors by means of a 2-dimensional rotational symmetry. We prove the stability of the vector sector by explicitly constructing the positive definite Hamiltonian. To reveal a mechanism for the stabilization of a superconducting phase, we construct a quadratic action for the scalar sector. From the action, we see the stability of black holes near a critical point is determined by the equation of motion for a charged scalar field. We show the effective mass of the charged scalar field in hairy black holes is always above the Breitenlohner-Freedman bound near the critical point due to the backreaction of a gauge field. It implies the stability of the superconducting phase. We also argue that the stability continues away from the critical point.
Stability of holographic superconductors
NASA Astrophysics Data System (ADS)
Kanno, Sugumi; Soda, Jiro
2010-10-01
We study the dynamical stability of holographic superconductors. We first classify perturbations around black hole background solutions into vector and scalar sectors by means of a 2-dimensional rotational symmetry. We prove the stability of the vector sector by explicitly constructing the positive definite Hamiltonian. To reveal a mechanism for the stabilization of a superconducting phase, we construct a quadratic action for the scalar sector. From the action, we see the stability of black holes near a critical point is determined by the equation of motion for a charged scalar field. We show the effective mass of the charged scalar field in hairy black holes is always above the Breitenlohner-Freedman bound near the critical point due to the backreaction of a gauge field. It implies the stability of the superconducting phase. We also argue that the stability continues away from the critical point.
Holographic Recording Materials Development
NASA Technical Reports Server (NTRS)
Verber, C. M.; Schwerzel, R. E.; Perry, P. J.; Craig, R. A.
1976-01-01
Organic photorefractive materials were evaluated for application in a reversible holographic memory system. Representative indigo and thioindigo derivatives and several stilbene derivatives were studied as well as 15, 16-dialkyldihydropyrene derivatives the following goals were achieved: (1) the successful writing of phase holograms in a thioindigo/polymer gel system, (2) the successful writing and erasing of phase holograms in a variety of indigo/polymer gel and indigo/solid polymer systems, and (3) the identification of indigoid dyes and 15, 16-dialkyldihydropyrene derivatives as materials potentially suitable for utilization in an operational system. Photochemical studies of the stilbene, indigo, thioindigo, and dialkyldihydropyrene derivatives in solution and in a variety of polymer matrix materials were conducted with the goal of optimizing the photorefractive behavior of the chemical system as a whole. The spectroscopic properties required of optimal photorefractive materials were identified, and it was shown that both the indigoid dyes and the dialkyldihydropyrenes closely match the required properties.
3D holographic printer: fast printing approach.
Morozov, Alexander V; Putilin, Andrey N; Kopenkin, Sergey S; Borodin, Yuriy P; Druzhin, Vladislav V; Dubynin, Sergey E; Dubinin, German B
2014-02-10
This article describes the general operation principles of devices for synthesized holographic images such as holographic printers. Special emphasis is placed on the printing speed. In addition, various methods to increase the printing process are described and compared.
Digital Holographic Interferometry for Airborne Particle Characterization
2015-03-19
hologram and its extinction cross section, and a computational demonstration that holographic interferometry can resolve aerosol particle size ...holographic interferometry can resolve aerosol particle size evolution. (a) Papers published in peer-reviewed journals (N/A for none) Enter List of...Characterization of Atmospheric Aerosols workshop, Smolenice, Slovak Republic (2013). 7. Poster : Digital Holographic Imaging of Aerosol Particles In-Flight
Holographic optical elements: Fabrication and testing
NASA Technical Reports Server (NTRS)
Zech, R. G.; Shareck, M.; Ralston, L. M.
1974-01-01
The basic properties and use of holographic optical elements were investigated to design and construct wide-angle, Fourier-transform holographic optical systems for use in a Bragg-effect optical memory. The performance characteristics are described along with the construction of the holographic system.
Fourier holographic display for augmented reality using holographic optical element
NASA Astrophysics Data System (ADS)
Li, Gang; Lee, Dukho; Jeong, Youngmo; Lee, Byoungho
2016-03-01
A method for realizing a three-dimensional see-through augmented reality in Fourier holographic display is proposed. A holographic optical element (HOE) with the function of Fourier lens is adopted in the system. The Fourier hologram configuration causes the real scene located behind the lens to be distorted. In the proposed method, since the HOE is transparent and it functions as the lens just for Bragg matched condition, there is not any distortion when people observe the real scene through the lens HOE (LHOE). Furthermore, two optical characteristics of the recording material are measured for confirming the feasibility of using LHOE in the proposed see-through augmented reality holographic display. The results are verified experimentally.
NASA Astrophysics Data System (ADS)
Andersen, G.
For the last two decades adaptive optics has been used as a technique for correcting imaging applications and directed energy/laser targeting and laser communications systems affected by atmospheric turbulence. Typically these systems are bulky and limited to <10 kHz due to large computing overhead and limited photon efficiencies. Moreover most use zonal wavefront sensors which cannot easily handle extreme scintillation or unexpected obscuration of a pre-set aperture. Here we present a compact, lightweight adaptive optics system with the potential to operate at speeds of MHz. The system utilizes a hologram to perform an all-optical wavefront analysis that removes the need for any computer. Finally, the sensing is made on a modal basis so it is largely insensitive to scintillation and obscuration. We have constructed a prototype device and will present experimental results from our research. The holographic adaptive optics system begins with the creation of a multiplexed hologram. This hologram is created by recording the maximum and minimum response functions of every actuator in the deformable mirror against a unique focused reference beam. When a wavefront of some arbitrary phase is incident on the processed hologram, a number of focal spots are created -- one pair for each actuator in the DM. The absolute phase error at each particular actuator location is simply related to the ratio of the intensity of each pair of spots. In this way we can use an array of photodetectors to give a direct readout of phase error without the need for any calculations. The advantages of holographic adaptive optics are many. To begin with, the measurement of phase error is made all optically, so the wavefront sensor directly controls the actuators in the DM without any computers. Using fast, photon counting photodetectors allows for closed loop correction limited only by the speed of the deformable mirror which in the case of MEMS devices can be 100 kHz or more. All this can be
Holographic p-Wave Superconductors in Quintessence AdS Black Hole Spacetime
NASA Astrophysics Data System (ADS)
Chen, Song-Bai; Pan, Qi-Yuan
2013-10-01
We construct a holographic p-wave superconductor model in the background of quintessence AdS black hole with an SU(2) Yang—Mills gauge field and then probe the effects of quintessence on the holographic p-wave superconductor. We investigate the relation between the critical temperature and the state parameter of quintessence, and present the numerical results for electric conductivity. It is shown that the condensation of the vector field becomes harder as the absolute value of the state parameter increases. Unlike the scalar condensate in the s-wave model, the condensation of the vector field in p-wave model can occur in the total value range of the state parameter wq of quintessence. These results could help us know more about holographic superconductor and dark energy.
Dark Matter Decays from Nonminimal Coupling to Gravity.
Catà, Oscar; Ibarra, Alejandro; Ingenhütt, Sebastian
2016-07-08
We consider the standard model extended with a dark matter particle in curved spacetime, motivated by the fact that the only current evidence for dark matter is through its gravitational interactions, and we investigate the impact on the dark matter stability of terms in the Lagrangian linear in the dark matter field and proportional to the Ricci scalar. We show that this "gravity portal" induces decay even if the dark matter particle only has gravitational interactions, and that the decay branching ratios into standard model particles only depend on one free parameter: the dark matter mass. We study in detail the case of a singlet scalar as a dark matter candidate, which is assumed to be absolutely stable in flat spacetime due to a discrete Z_{2} symmetry, but which may decay in curved spacetimes due to a Z_{2}-breaking nonminimal coupling to gravity. We calculate the dark matter decay widths and we set conservative limits on the nonminimal coupling parameter from experiments. The limits are very stringent and suggest that there must exist an additional mechanism protecting the singlet scalar from decaying via this gravity portal.
Full Color Holographic Endoscopy
NASA Astrophysics Data System (ADS)
Osanlou, A.; Bjelkhagen, H.; Mirlis, E.; Crosby, P.; Shore, A.; Henderson, P.; Napier, P.
2013-02-01
The ability to produce color holograms from the human tissue represents a major medical advance, specifically in the areas of diagnosis and teaching. This has been achieved at Glyndwr University. In corporation with partners at Gooch & Housego, Moor Instruments, Vivid Components and peninsula medical school, Exeter, UK, for the first time, we have produced full color holograms of human cell samples in which the cell boundary and the nuclei inside the cells could be clearly focused at different depths - something impossible with a two-dimensional photographic image. This was the main objective set by the peninsula medical school at Exeter, UK. Achieving this objective means that clinically useful images essentially indistinguishable from the object human cells could be routinely recorded. This could potentially be done at the tip of a holo-endoscopic probe inside the body. Optimised recording exposure and development processes for the holograms were defined for bulk exposures. This included the optimisation of in-house recording emulsions for coating evaluation onto polymer substrates (rather than glass plates), a key step for large volume commercial exploitation. At Glyndwr University, we also developed a new version of our in-house holographic (world-leading resolution) emulsion.
Cylindrical holographic radar camera
NASA Astrophysics Data System (ADS)
McMakin, Douglas L.; Sheen, David M.; Hall, Thomas E.; Severtsen, Ronald H.
1998-12-01
A novel personnel surveillance system has been developed to rapidly obtain 360 degree, full-body images of humans for the detection and identification of concealed threats. Detectable threats include weapons fabricated with metal, plastic, and ceramic, as well as explosive solids and liquids. This new system uses a cylindrical mechanical scanner to move a seven-foot, 384 element, Ka band (26 - 30 GHz) array circumferentially around a person in four to seven seconds. Low power millimeter-waves, which are nonionizing and not harmful to humans, are employed because they readily penetrate clothing barriers and reflect from concealed threats. The reflected waves provide information that is reconstructed into 3-D cylindrical holographic images with high-speed, digital signal processing (DSP) boards. This system is capable of displaying in an animation format eight, sixteen, thirty-two or sixty-four image frames at various aspect angles around the person under surveillance. This new prototype surveillance system is operational and is presently under laboratory testing and evaluation.
Constraining holographic inflation with WMAP
Easther, Richard; Flauger, Raphael; McFadden, Paul; Skenderis, Kostas E-mail: Raphael.Flauger@yale.edu E-mail: K.Skenderis@uva.nl
2011-09-01
In a class of recently proposed models, the early universe is strongly coupled and described holographically by a three-dimensional, weakly coupled, super-renormalizable quantum field theory. This scenario leads to a power spectrum of scalar perturbations that differs from the usual empirical ΛCDM form and the predictions of generic models of single field, slow roll inflation. This spectrum is characterized by two parameters: an amplitude, and a parameter g related to the coupling constant of the dual theory. We estimate these parameters, using WMAP and other astrophysical data. We compute Bayesian evidence for both the holographic model and standard ΛCDM and find that their difference is not significant, although ΛCDM provides a somewhat better fit to the data. However, it appears that Planck will permit a definitive test of this holographic scenario.
Holographic photolysis of caged neurotransmitters
Lutz, Christoph; Otis, Thomas S.; DeSars, Vincent; Charpak, Serge; DiGregorio, David A.; Emiliani, Valentina
2009-01-01
Stimulation of light-sensitive chemical probes has become a powerful tool for the study of dynamic signaling processes in living tissue. Classically, this approach has been constrained by limitations of lens–based and point-scanning illumination systems. Here we describe a novel microscope configuration that incorporates a nematic liquid crystal spatial light modulator (LC-SLM) to generate holographic patterns of illumination. This microscope can produce illumination spots of variable size and number and patterns shaped to precisely match user-defined elements in a specimen. Using holographic illumination to photolyse caged glutamate in brain slices, we demonstrate that shaped excitation on segments of neuronal dendrites and simultaneous, multi-spot excitation of different dendrites enables precise spatial and rapid temporal control of glutamate receptor activation. By allowing the excitation volume shape to be tailored precisely, the holographic microscope provides an extremely flexible method for activation of various photosensitive proteins and small molecules. PMID:19160517
Holographic characterization of protein aggregates
NASA Astrophysics Data System (ADS)
Wang, Chen; Zhong, Xiao; Ruffner, David; Stutt, Alexandra; Philips, Laura; Ward, Michael; Grier, David
Holographic characterization directly measures the size distribution of subvisible protein aggregates in suspension and offers insights into their morphology. Based on holographic video microscopy, this analytical technique records and interprets holograms of individual aggregates in protein solutions as they flow down a microfluidic channel, without requiring labeling or other exceptional sample preparation. The hologram of an individual protein aggregate is analyzed in real time with the Lorenz-Mie theory of light scattering to measure that aggregate's size and optical properties. Detecting, counting and characterizing subvisible aggregates proceeds fast enough for time-resolved studies, and lends itself to tracking trends in protein aggregation arising from changing environmental factors. No other analytical technique provides such a wealth of particle-resolved characterization data in situ. Holographic characterization promises accelerated development of therapeutic protein formulations, improved process control during manufacturing, and streamlined quality assurance during storage and at the point of use. Mrsec and MRI program of the NSF, Spheryx Inc.
Holographic films from carotenoid pigments
NASA Astrophysics Data System (ADS)
Toxqui-López, S.; Lecona-Sánchez, J. F.; Santacruz-Vázquez, C.; Olivares-Pérez, A.; Fuentes-Tapia, I.
2014-02-01
Carotenoids pigments presents in pineapple can be more than just natural dyes, which is one of the applications that now at day gives the chemical industry. In this research shown that can be used in implementing of holographic recording Films. Therefore we describe the technique how to obtain this kind of pigments trough spay drying of natural pineapple juice, which are then dissolved with water in a proportion of 0.1g to 1mL. The obtained sample is poured into glass substrates using the gravity method, after a drying of 24 hours in laboratory normal conditions the films are ready. The films are characterized by recording transmission holographic gratings (LSR 445 NL 445 nm) and measuring the diffraction efficiency holographic parameter. This recording material has good diffraction efficiency and environmental stability.
Composite Higgs models, Dark Matter and {lambda}
Diaz Cruz, J. Lorenzo
2009-04-20
We suggest that dark matter can be identified with a stable composite fermion X{sup 0}, that arises within the holographic AdS/CFT models, where the Higgs boson emerges as a composite pseudo-goldstone boson. The predicted properties of X{sup 0} satisfies the cosmological bounds, with m{sub X{sup 0}}{approx}4{pi}f{approx_equal}O(TeV). Thus, through a deeper understanding of the mechanism of electroweak symmetry breaking, a resolution of the Dark Matter enigma is found. Furthermore, by proposing a discrete structure of the Higgs vacuum, one can get a distinct approach to the cosmological constant problem.
DHMI: dynamic holographic microscopy interface
NASA Astrophysics Data System (ADS)
He, Xuefei; Zheng, Yujie; Lee, Woei Ming
2016-12-01
Digital holographic microscopy (DHM) is a powerful in-vitro biological imaging tool. In this paper, we report a fully automated off-axis digital holographic microscopy system completed with a graphical user interface in the Matlab environment. The interface primarily includes Fourier domain processing, phase reconstruction, aberration compensation and autofocusing. A variety of imaging operations such as region of interest selection, de-noising mode (filtering and averaging), low frame rate imaging for immediate reconstruction and high frame rate imaging routine ( 27 fps) are implemented to facilitate ease of use.
Glueball decay in holographic QCD
Hashimoto, Koji; Tan, C.-I; Terashima, Seiji
2008-04-15
Using holographic QCD based on D4-branes and D8-anti-D8-branes, we have computed couplings of glueballs to light mesons. We describe glueball decay by explicitly calculating its decay widths and branching ratios. Interestingly, while glueballs remain less well understood both theoretically and experimentally, our results are found to be consistent with the experimental data for the scalar glueball candidate f{sub 0}(1500). More generally, holographic QCD predicts that decay of any glueball to 4{pi}{sup 0} is suppressed, and that mixing of the lightest glueball with qq mesons is small.
Dark Energy from Discrete Spacetime
Trout, Aaron D.
2013-01-01
Dark energy accounts for most of the matter-energy content of our universe, yet current theories of its origin rely on radical physical assumptions such as the holographic principle or controversial anthropic arguments. We give a better motivated explanation for dark energy, claiming that it arises from a small negative scalar-curvature present even in empty spacetime. The vacuum has this curvature because spacetime is fundamentally discrete and there are more ways for a discrete geometry to have negative curvature than positive. We explicitly compute this effect using a variant of the well known dynamical-triangulations (DT) model for quantum gravity. Our model predicts a time-varying non-zero cosmological constant with a current value, in natural units, in agreement with observation. This calculation is made possible by a novel characterization of the possible DT action values combined with numerical evidence concerning their degeneracies. PMID:24312502
Dark energy from discrete spacetime.
Trout, Aaron D
2013-01-01
Dark energy accounts for most of the matter-energy content of our universe, yet current theories of its origin rely on radical physical assumptions such as the holographic principle or controversial anthropic arguments. We give a better motivated explanation for dark energy, claiming that it arises from a small negative scalar-curvature present even in empty spacetime. The vacuum has this curvature because spacetime is fundamentally discrete and there are more ways for a discrete geometry to have negative curvature than positive. We explicitly compute this effect using a variant of the well known dynamical-triangulations (DT) model for quantum gravity. Our model predicts a time-varying non-zero cosmological constant with a current value, [Formula: see text] in natural units, in agreement with observation. This calculation is made possible by a novel characterization of the possible DT action values combined with numerical evidence concerning their degeneracies.
Dark matter from f (R ,T ) gravity
NASA Astrophysics Data System (ADS)
Zaregonbadi, Raziyeh; Farhoudi, Mehrdad; Riazi, Nematollah
2016-10-01
We consider the f (R ,T ) modified theory of gravity, in which the gravitational Lagrangian is given by an arbitrary function of the Ricci scalar and the trace of the energy-momentum tensor of the matter, in order to investigate the dark-matter effects on the galaxy scale. We obtain the metric components for a spherically symmetric and static spacetime in the vicinity of general relativity solutions. However, we concentrate on a specific model of the theory where the matter is minimally coupled to the geometry, and derive the metric components in the galactic halo. Then, we fix the components by the rotational velocities of the galaxies for the model, and show that the mass corresponding to the interaction term (which appears in the Einstein modified field equation) leads to a flat rotation curve in the halo of galaxies. In addition, for the proposed model, the light-deflection angle has been derived and drawn using some observed data.
Variable deceleration parameter and dark energy models
NASA Astrophysics Data System (ADS)
Bishi, Binaya K.
2016-03-01
This paper deals with the Bianchi type-III dark energy model and equation of state parameter in a first class of f(R,T) gravity. Here, R and T represents the Ricci scalar and trace of the energy momentum tensor, respectively. The exact solutions of the modified field equations are obtained by using (i) linear relation between expansion scalar and shear scalar, (ii) linear relation between state parameter and skewness parameter and (iii) variable deceleration parameter. To obtain the physically plausible cosmological models, the variable deceleration parameter with the suitable substitution leads to the scale factor of the form a(t) = [sinh(αt)] 1 n, where α and n > 0 are arbitrary constants. It is observed that our models are accelerating for 0 < n < 1 and for n > 1, transition phase from deceleration to acceleration. Further, we have discussed physical properties of the models.
Loop quantum gravity, exact holographic mapping, and holographic entanglement entropy
NASA Astrophysics Data System (ADS)
Han, Muxin; Hung, Ling-Yan
2017-01-01
The relation between loop quantum gravity (LQG) and tensor networks is explored from the perspectives of the bulk-boundary duality and holographic entanglement entropy. We find that the LQG spin-network states in a space Σ with boundary ∂Σ is an exact holographic mapping similar to the proposal in [X.-L. Qi, Exact holographic mapping and emergent space-time geometry, arXiv:1309.6282]. The tensor network, understood as the boundary quantum state, is the output of the exact holographic mapping emerging from a coarse-graining procedure of spin networks. Furthermore, when a region A and its complement A ¯ are specified on the boundary ∂Σ , we show that the boundary entanglement entropy S (A ) of the emergent tensor network satisfies the Ryu-Takayanagi formula in the semiclassical regime, i.e., S (A ) is proportional to the minimal area of the bulk surface attached to the boundary of A in ∂Σ .
Joseph Silk
2016-07-12
One of the greatest mysteries in the cosmos is that it is mostly dark.Â Astronomers and particle physicists today are seeking to unravel the nature of this mysterious, but pervasive dark matter which has profoundly influenced the formation of structure in the universe. Â I will describe the complex interplay between galaxy formation and dark matter detectability and review recent attempts to measure particle dark matter by direct and indirect means.
NASA Technical Reports Server (NTRS)
Knopp, Jerome
1996-01-01
Astronauts are required to interface with complex systems that require sophisticated displays to communicate effectively. Lightweight, head-mounted real-time displays that present holographic images for comfortable viewing may be the ideal solution. We describe an implementation of a liquid crystal television (LCTV) as a spatial light modulator (SLM) for the display of holograms. The implementation required the solution of a complex set of problems. These include field calculations, determination of the LCTV-SLM complex transmittance characteristics and a precise knowledge of the signal mapping between the LCTV and frame grabbing board that controls it. Realizing the hologram is further complicated by the coupling that occurs between the phase and amplitude in the LCTV transmittance. A single drive signal (a gray level signal from a framegrabber) determines both amplitude and phase. Since they are not independently controllable (as is true in the ideal SLM) one must deal with the problem of optimizing (in some sense) the hologram based on this constraint. Solutions for the above problems have been found. An algorithm has been for field calculations that uses an efficient outer product formulation. Juday's MEDOF 7 (Minimum Euclidean Distance Optimal Filter) algorithm used for originally for filter calculations has been successfully adapted to handle metrics appropriate for holography. This has solved the problem of optimizing the hologram to the constraints imposed by coupling. Two laboratory methods have been developed for determining an accurate mapping of framegrabber pixels to LCTV pixels. A friendly software system has been developed that integrates the hologram calculation and realization process using a simple set of instructions. The computer code and all the laboratory measurement techniques determining SLM parameters have been proven with the production of a high quality test image.
NASA Astrophysics Data System (ADS)
Debnath, Ujjal
2015-12-01
In this work, we have studied accretion of the dark matter and dark energy onto of (n+2)-dimensional Schwarzschild black hole and Morris-Thorne wormhole. The mass and the rate of change of mass for (n+2)-dimensional Schwarzschild black hole and Morris-Thorne wormhole have been found. We have assumed some candidates of dark energy like holographic dark energy, new agegraphic dark energy, quintessence, tachyon, DBI-essence, etc. The black hole mass and the wormhole mass have been calculated in term of redshift when dark matter and above types of dark energies accrete onto them separately. We have shown that the black hole mass increases and wormhole mass decreases for holographic dark energy, new agegraphic dark energy, quintessence, tachyon accretion and the slope of increasing/decreasing of mass sensitively depends on the dimension. But for DBI-essence accretion, the black hole mass first increases and then decreases and the wormhole mass first decreases and then increases and the slope of increasing/decreasing of mass not sensitively depends on the dimension.
Holographic Twyman-Green Interferometer
NASA Technical Reports Server (NTRS)
Chen, C. W.; Wyant, J. C.; Breckinridge, J. B.
1984-01-01
Off-axis Fresnel zone plate used to obtain fringe visibility close to unity. Holographic Twyman-Green Interferometer (HTG) employs off-axis Fresnel zone plate (OFZP) as beam splitter and beam diverger in place of two separate elements that perform those functions in conventional TwymanGreen interferometer.
Music holographic physiotherapy by laser
NASA Astrophysics Data System (ADS)
Liao, Changhuan
1996-09-01
Based on the relationship between music and nature, the paper compares laser and light with music sound on the principles of synergetics, describes music physically and objectively, and proposes a music holographic therapy by laser. Maybe it will have certain effects on mechanism study and clinical practice of the music therapy.
Holographic enhanced remote sensing system
NASA Technical Reports Server (NTRS)
Iavecchia, Helene P.; Gaynor, Edwin S.; Huff, Lloyd; Rhodes, William T.; Rothenheber, Edward H.
1990-01-01
The Holographic Enhanced Remote Sensing System (HERSS) consists of three primary subsystems: (1) an Image Acquisition System (IAS); (2) a Digital Image Processing System (DIPS); and (3) a Holographic Generation System (HGS) which multiply exposes a thermoplastic recording medium with sequential 2-D depth slices that are displayed on a Spatial Light Modulator (SLM). Full-parallax holograms were successfully generated by superimposing SLM images onto the thermoplastic and photopolymer. An improved HGS configuration utilizes the phase conjugate recording configuration, the 3-SLM-stacking technique, and the photopolymer. The holographic volume size is currently limited to the physical size of the SLM. A larger-format SLM is necessary to meet the desired 6 inch holographic volume. A photopolymer with an increased photospeed is required to ultimately meet a display update rate of less than 30 seconds. It is projected that the latter two technology developments will occur in the near future. While the IAS and DIPS subsystems were unable to meet NASA goals, an alternative technology is now available to perform the IAS/DIPS functions. Specifically, a laser range scanner can be utilized to build the HGS numerical database of the objects at the remote work site.
Holographic microscopy in low coherence
NASA Astrophysics Data System (ADS)
Chmelík, Radim; Petráček, Jiří; Slabá, Michala; Kollárová, Věra; Slabý, Tomáš; Čolláková, Jana; Komrska, Jiří; Dostál, Zbyněk.; Veselý, Pavel
2016-03-01
Low coherence of the illumination substantially improves the quality of holographic and quantitative phase imaging (QPI) by elimination of the coherence noise and various artefacts and by improving the lateral resolution compared to the coherent holographic microscopy. Attributes of coherence-controlled holographic microscope (CCHM) designed and built as an off-axis holographic system allowing QPI within the range from complete coherent to incoherent illumination confirmed these expected advantages. Low coherence illumination also furnishes the coherence gating which constraints imaging of some spatial frequencies of an object axially thus forming an optical section in the wide sense. In this way the depth discrimination capability of the microscope is introduced at the price of restricting the axial interval of possible numerical refocusing. We describe theoretically these effects for the whole range of illumination coherence. We also show that the axial refocusing constraints can be overcome using advanced mode of imaging based on mutual lateral shift of reference and object image fields in CCHM. Lowering the spatial coherence of illumination means increasing its numerical aperture. We study how this change of the illumination geometry influences 3D objects QPI and especially the interpretation of live cells QPI in terms of the dry mass density measurement. In this way a strong dependence of the imaging process on the light coherence is demonstrated. The theoretical calculations and numerical simulations are supported by experimental data including a chance of time-lapse watching of live cells even in optically turbid milieu.
Shi, Jie; Stonnington, Cynthia M; Thompson, Paul M; Chen, Kewei; Gutman, Boris; Reschke, Cole; Baxter, Leslie C; Reiman, Eric M; Caselli, Richard J; Wang, Yalin
2015-01-01
Mild Cognitive Impairment (MCI) is a transitional stage between normal aging and dementia and people with MCI are at high risk of progression to dementia. MCI is attracting increasing attention, as it offers an opportunity to target the disease process during an early symptomatic stage. Structural magnetic resonance imaging (MRI) measures have been the mainstay of Alzheimer's disease (AD) imaging research, however, ventricular morphometry analysis remains challenging because of its complicated topological structure. Here we describe a novel ventricular morphometry system based on the hyperbolic Ricci flow method and tensor-based morphometry (TBM) statistics. Unlike prior ventricular surface parameterization methods, hyperbolic conformal parameterization is angle-preserving and does not have any singularities. Our system generates a one-to-one diffeomorphic mapping between ventricular surfaces with consistent boundary matching conditions. The TBM statistics encode a great deal of surface deformation information that could be inaccessible or overlooked by other methods. We applied our system to the baseline MRI scans of a set of MCI subjects from the Alzheimer's Disease Neuroimaging Initiative (ADNI: 71 MCI converters vs. 62 MCI stable). Although the combined ventricular area and volume features did not differ between the two groups, our fine-grained surface analysis revealed significant differences in the ventricular regions close to the temporal lobe and posterior cingulate, structures that are affected early in AD. Significant correlations were also detected between ventricular morphometry, neuropsychological measures, and a previously described imaging index based on fluorodeoxyglucose positron emission tomography (FDG-PET) scans. This novel ventricular morphometry method may offer a new and more sensitive approach to study preclinical and early symptomatic stage AD.
Shi, Jie; Stonnington, Cynthia M.; Thompson, Paul M.; Chen, Kewei; Gutman, Boris; Reschke, Cole; Baxter, Leslie C.; Reiman, Eric M.; Caselli, Richard J.; Wang, Yalin
2014-01-01
Mild Cognitive Impairment (MCI) is a transitional stage between normal aging and dementia and people with MCI are at high risk of progression to dementia. MCI is attracting increasing attention, as it offers an opportunity to target the disease process during an early symptomatic stage. Structural magnetic resonance imaging (MRI) measures have been the mainstay of Alzheimer’s disease (AD) imaging research, however, ventricular morphometry analysis remains challenging because of its complicated topological structure. Here we describe a novel ventricular morphometry system based on the hyperbolic Ricci flow method and tensor-based morphometry (TBM) statistics. Unlike prior ventricular surface parameterization methods, hyperbolic conformal parameterization is angle-preserving and does not have any singularities. Our system generates a one-to-one diffeomorphic mapping between ventricular surfaces with consistent boundary matching conditions. The TBM statistics encode a great deal of surface deformation information that could be inaccessible or overlooked by other methods. We applied our system to the baseline MRI scans of a set of MCI subjects from the Alzheimer’s Disease Neuroimaging Initiative (ADNI: 71 MCI converters vs. 62 MCI stable). Although the combined ventricular area and volume features did not differ between the two groups, our fine-grained surface analysis revealed significant differences in the ventricular regions close to the temporal lobe and posterior cingulate, structures that are affected early in AD. Significant correlations were also detected between ventricular morphometry, neuropsychological measures, and a previously described imaging index based on fluorodeoxyglucose positron emission tomography (FDG-PET) scans. This novel ventricular morphometry method may offer a new and more sensitive approach to study preclinical and early symptomatic stage AD. PMID:25285374
Yang-Mills instantons sitting on a Ricci-flat worldspace of double D4-branes
Kim, Hongsu; Yoon, Yongsung
2001-06-15
Thus far, there seem to be no complete criteria that can settle the issue as to what the correct generalization of the Dirac-Born-Infeld (DBI) action, describing the low-energy dynamics of the D-branes, to the non-Abelian case would be. According to recent suggestions, one might pass the issue of worldvolume solitons from an Abelian to non-Abelian setting by considering the stack of multiple, coincident D-branes and use it as a guideline to construct or censor the relevant non-Abelian version of the DBI action. In this spirit, here we are interested in the explicit construction of SU(2) Yang-Mills (YM) instanton solutions in the background geometry of two coincident probe D4-brane worldspaces, particularly when the metric of the target spacetime in which the probe branes are embedded is given by the Ricci-flat, magnetic extremal 4-brane solution in type IIA supergravity theory with its worldspace metric being given by that of Taub{endash}Newman-Unti-Tamburino (NUT) and Eguchi-Hanson solutions, the two best-known gravitational instantons. Then we demonstrate that, with this YM instanton-gravitational instanton configuration on the probe D4-brane worldvolume, the energy of the probe branes attains its minimum value and hence enjoys a stable state provided one employs Tseytlin's non-Abelian DBI action for the description of multiple probe D-branes. In this way, we support the arguments in the literature in favor of Tseytlin's proposal for the non-Abelian DBI action.
Investigation of uses of holographic optical elements
NASA Technical Reports Server (NTRS)
Zech, R. G.; Latta, J. N.
1973-01-01
The data represent a thorough study of the aberrations and imaging properties of holographic optical elements. Principle studies include (1) the indepth experimental investigation of single holographic optical elements, (2) the verification of the accuracy of the theoretical computer-based description of hologram behavior, (3) the computer-generation of interferograms that are characteristic of a prescribed aberrated imaging condition, (4) the experimental verification of wavelength optimization, (5) the experimental determination of the space bandwidth product of single holographic optical elements as a function of bending and field angle, and (6) the first experimental study of the aberration properties of holographic optical elements constructed in very thick (750 microns) recording media.
Understanding strongly coupling magnetism from holographic duality
NASA Astrophysics Data System (ADS)
Cai, Rong-Gen; Yang, Run-Qiu
2016-07-01
The unusual magnetic materials are significant in both science and technology. However, because of the strongly correlated effects, it is difficult to understand their novel properties from theoretical aspects. Holographic duality offers a new approach to understanding such systems from gravity side. This paper will give a brief review of our recent works on the applications of holographic duality in understanding unusual magnetic materials. Some quantitative comparision between holographic results and experimental data will be shown and some predictions from holographic duality models will be discussed.
Holographic Routing Network For Parallel Processing Machines
NASA Astrophysics Data System (ADS)
Maniloff, Eric S.; Johnson, Kristina M.; Reif, John H.
1989-10-01
Dynamic holographic architectures for connecting processors in parallel computers have been generally limited by the response time of the holographic recording media. In this paper we present a different approach to dynamic optical interconnects involving spatial light modulators (SLMs) and volume holograms. Multiple-exposure holograms are stored in a volume recording media, which associate the address of a destination processor encoded on a spatial light modulator with a distinct reference beam. A destination address programmed on the spatial light modulator is then holographically steered to the correct destination processor. We present the design and experimental results of a holographic router for connecting four originator processors to four destination processors.
Vachaspati, Tanmay
2009-09-15
Recent astrophysical observations have motivated novel theoretical models of the dark matter sector. A class of such models predicts the existence of GeV scale cosmic strings that communicate with the standard model sector by Aharonov-Bohm interactions with electrically charged particles. We discuss the cosmology of these 'dark strings' and investigate possible observational signatures. More elaborate dark sector models are argued to contain hybrid topological defects that may also have observational signatures.
Progress in the printing techniques of the holographic stereogram
NASA Astrophysics Data System (ADS)
Jiang, Xiaoyu; Cheng, Changqing; Yan, Xingpeng; Zhao, Kai; Yan, Zhiqiang
2015-10-01
Holographic stereogram display technology is one of the research focuses in three-dimensional (3D) holographic display. Holographic stereogram is essentially to infinitely approach the true 3D object using a sequence of 2D perspective images. In this paper, several holographic printing methods are summarized firstly, including two-steps transfer hologram printing technique, horizontal parallax only (HPO) stereogram with laser direct writing and holographic elements based full-parallax holographic stereogram method. Also the principles of printing, method of recording, and the various factors that affect the printing quality of the holographic stereogram are discussed and analyzed in detail. Then, after designing the matching relationship between full-parallax holographic stereogram and holographic elements, a new method to print holographic stereogram is proposed. With this method, image distortions can be decreased to improve the printing quality because this method has less impact factors and easier operations in experiment. Finally, it points out the recent development state of holographic stereogram.
Bashir, A.; Cotti, U.; De Leon, C. L.; Raya, A; Villasenor, L.
2008-07-02
One of the biggest scientific mysteries of our time resides in the identification of the particles that constitute a large fraction of the mass of our Universe, generically known as dark matter. We review the observations and the experimental data that imply the existence of dark matter. We briefly discuss the properties of the two best dark-matter candidate particles and the experimental techniques presently used to try to discover them. Finally, we mention a proposed project that has recently emerged within the Mexican community to look for dark matter.
Holographic Chern-Simons defects
Fujita, Mitsutoshi; Melby-Thompson, Charles M.; Meyer, René; ...
2016-06-28
Here, we study SU(N ) Yang-Mills-Chern-Simons theory in the presence of defects that shift the Chern-Simons level from a holographic point of view by embedding the system in string theory. The model is a D3-D7 system in Type IIB string theory, whose gravity dual is given by the AdS soliton background with probe D7 branes attaching to the AdS boundary along the defects. We holographically renormalize the free energy of the defect system with sources, from which we obtain the correlation functions for certain operators naturally associated to these defects. We find interesting phase transitions when the separation of themore » defects as well as the temperature are varied. We also discuss some implications for the Fractional Quantum Hall Effect and for 2-dimensional QCD.« less
Towards holographic quantum energy teleportation
NASA Astrophysics Data System (ADS)
Giataganas, Dimitrios; Lin, Feng-Li; Liu, Pei-Hua
2016-12-01
We propose a simplified protocol of quantum energy teleportation (QET) for the holographic conformal field theory in three-dimensional anti-de Sitter space with or without a black hole. As a tentative proposal, we simplify the standard QET by replacing Alice's local measurement with the local projection, which excites the system from the ground state into a particular state dual to a Banados geometry. We then mimic Bob's local operation of the usual QET for extracting energy by deforming the UV surface with a local bump. Adopting the surface-state duality, this deformation corresponds to local unitary. We evaluate the extraction of energy from the holographic stress tensor and find that Bob always gains energy extraction in our protocol. This could be related to the positive energy theorem of the dual gravity. Moreover, the ratio of extraction energy to the injection one is a universal function of the UV surface deformation profile.
Content-addressable holographic databases
NASA Astrophysics Data System (ADS)
Grawert, Felix; Kobras, Sebastian; Burr, Geoffrey W.; Coufal, Hans J.; Hanssen, Holger; Riedel, Marc; Jefferson, C. Michael; Jurich, Mark C.
2000-11-01
Holographic data storage allows the simultaneous search of an entire database by performing multiple optical correlations between stored data pages and a search argument. We have recently developed fuzzy encoding techniques for this fast parallel search and demonstrated a holographic data storage system that searches digital data records with high fidelity. This content-addressable retrieval is based on the ability to take the two-dimensional inner product between the search page and each stored data page. We show that this ability is lost when the correlator is defocussed to avoid material oversaturation, but can be regained by the combination of a random phase mask and beam confinement through total internal reflection. Finally, we propose an architecture in which spatially multiplexed holograms are distributed along the path of the search beam, allowing parallel search of large databases.
Holographic Chern-Simons defects
NASA Astrophysics Data System (ADS)
Fujita, Mitsutoshi; Melby-Thompson, Charles M.; Meyer, René; Sugimoto, Shigeki
2016-06-01
We study SU( N ) Yang-Mills-Chern-Simons theory in the presence of defects that shift the Chern-Simons level from a holographic point of view by embedding the system in string theory. The model is a D3-D7 system in Type IIB string theory, whose gravity dual is given by the AdS soliton background with probe D7 branes attaching to the AdS boundary along the defects. We holographically renormalize the free energy of the defect system with sources, from which we obtain the correlation functions for certain operators naturally associated to these defects. We find interesting phase transitions when the separation of the defects as well as the temperature are varied. We also discuss some implications for the Fractional Quantum Hall Effect and for 2-dimensional QCD.
Holographic Chern-Simons defects
Fujita, Mitsutoshi; Melby-Thompson, Charles M.; Meyer, René; Sugimoto, Shigeki
2016-06-28
Here, we study SU(N ) Yang-Mills-Chern-Simons theory in the presence of defects that shift the Chern-Simons level from a holographic point of view by embedding the system in string theory. The model is a D3-D7 system in Type IIB string theory, whose gravity dual is given by the AdS soliton background with probe D7 branes attaching to the AdS boundary along the defects. We holographically renormalize the free energy of the defect system with sources, from which we obtain the correlation functions for certain operators naturally associated to these defects. We find interesting phase transitions when the separation of the defects as well as the temperature are varied. We also discuss some implications for the Fractional Quantum Hall Effect and for 2-dimensional QCD.
Holographic Interferometry The Twentieth Anniversary
NASA Astrophysics Data System (ADS)
Pryputniewicz, Ryszard J.
1985-08-01
Professor Ryszard Pryputniewicz of Worcester Polytechnic Institute has assembled a significant group of papers on the subject of holographic interferometry in celebration of the first twenty years of activity in this field. Several of these papers were received too late for inclusion in this issue but will be published as a group in the next issue of Optical Engineering. Taken together, these papers are an indication of the tremendous progress made during the twenty years of this field's existence.
Disordered holographic systems: Functional renormalization
NASA Astrophysics Data System (ADS)
Adams, Allan; Yaida, Sho
2015-12-01
We study quenched disorder in strongly correlated systems via holography, focusing on the thermodynamic effects of mild electric disorder. Disorder is introduced through a random potential which is assumed to self-average on macroscopic scales. Studying the flow of this distribution with energy scale leads us to develop a holographic functional renormalization scheme. We test this scheme by computing thermodynamic quantities and confirming that the Harris criterion for relevance, irrelevance, or marginality of quenched disorder holds.
Holographic recording materials - A review
NASA Technical Reports Server (NTRS)
Kurtz, R. L.; Owen, R. B.
1975-01-01
Holographic recording materials in current use are examined along with a few of their applications. Some experimental media are also studied. No effort is made to rank the commercial materials, since satisfactory results can be obtained with any of them. The discussion covers silver halide plates and films, photoresists, thermoplastics, photopolymers, dichromated gelatin, photochromic materials, electrooptical crystals, styryl free radical film, and TEP film. A convenient summation of some material properties is presented in tabular form.
Design relationships for holographic memories.
NASA Technical Reports Server (NTRS)
Lugt, A. V.
1973-01-01
The maximum capacity of a block-oriented, random-access memory is determined primarily by the geometrical parameters of the lenses required to create a Fourier transform of a spatial bit pattern and to image the reconstructed bits onto a photodetector array. Furthermore, the maximum packing density is determined primarily by the same parameters. Several important relationships are developed that are useful in the preliminary design of holographic memories.
Advances in holographic particle velocimetry
NASA Astrophysics Data System (ADS)
Simmons, Scott; Meng, Hui; Hussain, Fazle; Liu, David
1993-12-01
Holographic particle velocimetry (HPV) is a promising technique for 3D flow velocity and hence vorticity measurements to study turbulence, coherent structures and vortex interactions. We discuss various aspects in the development of this technique ranging from hologram recording configurations such as in-line, off-axis and multibeam to data processing. Difficulties in implementation are analyzed and solutions are discussed. We also present preliminary measurement results in a 3D vortex flow using one of our prototype HPV systems.
Electromagnetic holographic imaging of bioimpedance
NASA Astrophysics Data System (ADS)
Smith, Dexter G.; Ko, Harvey W.; Lee, Benjamin R.; Partin, Alan W.
1998-05-01
The electromagnetic bioimpedance method has successfully measured the very subtle conductivity changes associated with brain edema and prostate tumor. This method provides noninvasive measurements using non-ionizing magnetic fields applied with a small coil that avoids the use of contact electrodes. This paper introduces results from combining a holographic signal processing algorithm and a low power coil system that helps provide the 3D image of impedance contrast that should make the noninvasive electromagnetic bioimpedance method useful in health care.
Pion condensation in holographic QCD
Albrecht, Dylan; Erlich, Joshua
2010-11-01
We study pion condensation at zero temperature in a hard-wall holographic model of hadrons with isospin chemical potential. We find that the transition from the hadronic phase to the pion condensate phase is first order except in a certain limit of model parameters. Our analysis suggests that immediately across the phase boundary the condensate acts as a stiff medium approaching the Zel'dovich limit of equal energy density and pressure.
Sound modes in holographic superfluids
Herzog, Christopher P.; Yarom, Amos
2009-11-15
Superfluids support many different types of sound waves. We investigate the relation between the sound waves in a relativistic and a nonrelativistic superfluid by using hydrodynamics to calculate the various sound speeds. Then, using a particular holographic scalar gravity realization of a strongly interacting superfluid, we compute first, second, and fourth sound speeds as a function of the temperature. The relativistic low temperature results for second sound differ from Landau's well known prediction for the nonrelativistic, incompressible case.
RGB digital lensless holographic microscopy
NASA Astrophysics Data System (ADS)
Garcia-Sucerquia, Jorge
2013-11-01
The recent introduction of color digital lensless holographic microscopy (CDLHM) has shown the possibility of imaging microscopic specimens at full color without the need of lenses. Owing to the simplicity, robustness, and compactness of the digital lensless holographic microscopes (DLHM), they have been presented as the ideal candidates to being developed into portable holographic microscopes. However, in the case of CDLHM the utilization of three independent lasers hinders the portability option for this microscope. In this contribution an alternative to reduce the complexity of CDLHM aimed to recover the portability of this microscopy technology is presented. A super-bright white-light light-emitting diode (LED) is spectrally and spatially filtered to produce the needed illumination by CDLHM to work. CDLHM with LED illumination is used to image at full color a section of the head of a drosophila melanogaster fly (fruit fly). The LED-CDLHM method shows the capability of imaging objects of 2μm size in comparison with the micrometer resolution reported for LASER-CDLHM.
Holographic cosmology from BIonic solutions
NASA Astrophysics Data System (ADS)
Sepehri, Alireza; Faizal, Mir; Setare, Mohammad Reza; Ali, Ahmed Farag
2017-02-01
In this paper, we will use a BIonic solution for analyzing the holographic cosmology. A BIonic solution is a configuration of a D3-brane and an anti-D3-brane connected by a wormhole, and holographic cosmology is a recent proposal to explain cosmic expansion by using the holographic principle. In our model, a BIonic configuration will be produced by the transition of fundamental black strings. The formation of a BIonic configuration will cause inflation. As the D3-brane moves away from the anti-D3-brane, the wormhole will get annihilated, and the inflation will end with the annihilation of this wormhole. However, it is possible for a D3-brane to collide with an anti-D3-brane. Such a collision will occur if the distance between the D3-brane and the anti-D3-brane reduces, and this will create tachyonic states. We will demonstrate that these tachyonic states will lead to the formation of a new wormhole, and this will cause acceleration of the universe before such a collision.
Dark matter and dark radiation
Ackerman, Lotty; Buckley, Matthew R.; Carroll, Sean M.; Kamionkowski, Marc
2009-01-15
We explore the feasibility and astrophysical consequences of a new long-range U(1) gauge field ('dark electromagnetism') that couples only to dark matter, not to the standard model. The dark matter consists of an equal number of positive and negative charges under the new force, but annihilations are suppressed if the dark-matter mass is sufficiently high and the dark fine-structure constant {alpha}-circumflex is sufficiently small. The correct relic abundance can be obtained if the dark matter also couples to the conventional weak interactions, and we verify that this is consistent with particle-physics constraints. The primary limit on {alpha}-circumflex comes from the demand that the dark matter be effectively collisionless in galactic dynamics, which implies {alpha}-circumflex < or approx. 10{sup -3} for TeV-scale dark matter. These values are easily compatible with constraints from structure formation and primordial nucleosynthesis. We raise the prospect of interesting new plasma effects in dark-matter dynamics, which remain to be explored.
Pereira-Dias, B.; Hernaski, C. A.; Helayeel-Neto, J. A.
2011-04-15
The combined effects of the Lorentz-symmetry violating Chern-Simons and Ricci-Cotton actions are investigated for the Einstein-Hilbert gravity in the second-order formalism modified by higher derivative terms, and their consequences on the spectrum of excitations are analyzed. We follow the lines of previous works and build up an orthonormal basis of projector-like operators for the degrees of freedom, rather than for the spin modes of the fields. With this new basis, the attainment of the propagators is remarkably simplified and the identification of the physical and unphysical modes becomes more immediate. Our conclusion is that the only tachyon- and ghost-free model is the Einstein-Hilbert action added up by the Chern-Simons term with a timelike vector of the type v{sup {mu}=}({mu},0-vector). Spectral consistency imposes that the Ricci-Cotton term must be switched off. We then infer that gravity with Lorentz-symmetry violation imposes a drastically different constraint on the background if compared to ordinary gauge theories whenever conditions for the suppression of tachyons and ghosts are imposed.
Monitoring by holographic radar systems
NASA Astrophysics Data System (ADS)
Catapano, Ilaria; Crocco, Lorenzo; Affinito, Antonio; Gennarelli, Gianluca; Soldovieri, Francesco
2013-04-01
Nowadays, radar technology represents a significant opportunity to collect useful information for the monitoring and conservation of critical infrastructures. Radar systems exploit the non-invasive interaction between the matter and the electromagnetic waves at microwave frequencies. Such an interaction allows obtaining images of the region under test from which one can infer the presence of potential anomalies such as deformations, cracks, water infiltrations, etc. This information turns out to be of primary importance in practical scenarios where the probed structure is in a poor state of preservation and renovation works must be planned. In this framework, the aim of this contribution is to describe the potentialities of the holographic radar Rascan 4/4000, a holographic radar developed by Remote Sensing Laboratory of Bauman Moscow State Technical University, as a non-destructive diagnostic tool capable to provide, in real-time, high resolution subsurface images of the sounded structure [1]. This radar provides holograms of hidden anomalies from the amplitude of the interference signal arising between the backscattered signal and a reference signal. The performance of the holographic radar is appraised by means of several experiments. Preliminary tests concerning the imaging below the floor and inside wood structures are carried out in controlled conditions at the Electromagnetic Diagnostic Laboratory of IREA-CNR. After, with reference to bridge monitoring for security aim, the results of a measurement campaign performed on the Musmeci bridge are presented [2]. Acknowledgments This research has been performed in the framework of the "Active and Passive Microwaves for Security and Subsurface imaging (AMISS)" EU 7th Framework Marie Curie Actions IRSES project (PIRSES-GA-2010-269157). REFERENCES [1] S. Ivashov, V. Razevig, I. Vasilyev, A. Zhuravlev, T. Bechtel, L. Capineri, The holographic principle in subsurface radar technology, International Symposium to
Anticounterfeit holographic marks with secret codes
NASA Astrophysics Data System (ADS)
Liu, Shou; Zhang, Xiangsu; Lai, Hongkai
1993-11-01
The paper introduces the methods of making secret codes in the holograms for the purpose of anti-counterfeiting, especially the production of two kinds of visual holographic secret codes. The optical arrangements for recording are presented, and the effective results from using the visual secret codes into holographic trade marks are reported.
Imaging characteristics of a volume holographic lens
NASA Astrophysics Data System (ADS)
Yang, Jing; Jiang, Zhu-qing; Xu, Zhi-qiang; Liu, Shao-jie; Sun, Ya-jun; Tao, Shi-quan
2009-07-01
A volume holographic grating lens can reconstruct the three-dimensional information by conducting multiple optical slicing of an object based on Bragg selectivity of the volume holographic grating. In this paper, we employ the point-spread function of volume holographic imaging system to theoretically analyze its imaging resolution. In the experiments, the volume holographic gratings are made with a spherical reference (SR) and a planar reference (PR), respectively, and used as volume holographic imaging lens in our imaging system. The longitudinal and lateral defocusing characteristics of volume holographic lens with SR and with PR are investigated experimentally by displacing the interested objects from original reference location, respectively. The effects of the parameters of the volume holographic lens on the longitudinal and lateral resolution are also discussed. The experimental results show that increasing the size of the volume holographic lens can improve the depth resolution, and in particular, it has greater influence on SR VHI. The lateral selectivity of SR VHI is more sensitive than that of PR VHI, and the Bragg degenerate diffraction of PR VHI on the y axis is obviously observed.
Real-time preprocessing of holographic information
NASA Astrophysics Data System (ADS)
Schilling, Bradley W.; Poon, Ting-Chung
1995-11-01
Optical scanning holography (OSH) is a holographic recording technique that uses active optical heterodyne scanning to generate holographic information pertaining to an object. The holographic information manifests itself as an electrical signal suitable for real-time image reconstruction using a spatial light modulator. The electrical signal that carries the holographic information can also be digitized for computer storage and processing, allowing the image reconstruction to be performed numerically. In previous experiments with this technique, holographic information has been recorded using the interference pattern of a plane wave and a spherical wave of different temporal frequencies to scan an object. However, the proper manipulation of the pupil functions in the recording stage can result in real-time processing of the holographic edge extraction technique as an important example of real-time preprocessing of holographic information that utilizes alternate pupils in the OSH recording stage. We investigate the theory of holographic preprocessing using a spatial frequency-domain analysis based on the recording system's optical transfer function. The theory is reinforced through computer simulation.
Holographic brain: a good analogy gone bad
NASA Astrophysics Data System (ADS)
Caulfield, H. John
2002-07-01
One way of honoring the world's two greatest holographers is to remove from their field the association with the offbeat world of the holographic mind. Basing itself on analogical musings of two very creative scientists who were themselves not holographers, this 'field' of the holographic brain has strayed far from science and into the absurd. So much absurdity has been written by so many people that the one legitimate study of holographic principle in dolphins has been grouped too often with the nonsense. Here is taken most of the 'target statements' form one book. We could not bear to read them all this closely. We will attempt to determine what tidbit of fact led to the statements and to suggest alternative explanations when there is something to explain.
Gavela, M.B.; Hernández, D.; Honorez, L. Lopez; Mena, O.; Rigolin, S. E-mail: d.hernandez@uam.es E-mail: omena@ific.uv.es
2009-07-01
The two dark sectors of the universe—dark matter and dark energy—may interact with each other. Background and linear density perturbation evolution equations are developed for a generic coupling. We then establish the general conditions necessary to obtain models free from non-adiabatic instabilities. As an application, we consider a viable universe in which the interaction strength is proportional to the dark energy density. The scenario does not exhibit ''phantom crossing'' and is free from instabilities, including early ones. A sizeable interaction strength is compatible with combined WMAP, HST, SN, LSS and H(z) data. Neutrino mass and/or cosmic curvature are allowed to be larger than in non-interacting models. Our analysis sheds light as well on unstable scenarios previously proposed.
ERIC Educational Resources Information Center
Lincoln, Don
2013-01-01
It's a dark, dark universe out there, and I don't mean because the night sky is black. After all, once you leave the shadow of the Earth and get out into space, you're surrounded by countless lights glittering everywhere you look. But for all of Sagan's billions and billions of stars and galaxies, it's a jaw-dropping fact that the ordinary kind of…
50 years of holographic interferometry
NASA Astrophysics Data System (ADS)
Stetson, Karl A.
2015-01-01
Fifty years ago, Robert L. Powell and I discovered holographic interferometry while working at the Radar Laboratory of the University of Michigan's Institute of Science and Technology. I have worked in this field for this entire time span, watched it grow from an unexplored technology to become a widespread industrial testing method, and I have contributed to these developments. In this paper, I will trace my history in this field from our discovery to my involvement in its theory and applications. I will conclude with a discussion of digital holography, which is currently replacing photographic holography for most research and industrial applications.
High speed holographic digital recorder.
Roberts, H N; Watkins, J W; Johnson, R H
1974-04-01
Concepts, feasibility experiments, and key component developments are described for a holographic digital record/reproduce system with the potential for 1.0 Gbit/sec rates and higher. Record rates of 500 Mbits/sec have been demonstrated with a ten-channel acoustooptic modulator array and a mode-locked, cavity-dumped argon-ion laser. Acoustooptic device technology has been advanced notably during the development of mode lockers, cavity dumpers, beam deflectors, and multichannel modulator arrays. The development of high speed multichannel photodetector arrays for the readout subsystem requires special attention. The feasibility of 1.0 Gbits/sec record rates has been demonstrated.
Holographic Complexity Equals Bulk Action?
NASA Astrophysics Data System (ADS)
Brown, Adam R.; Roberts, Daniel A.; Susskind, Leonard; Swingle, Brian; Zhao, Ying
2016-05-01
We conjecture that the quantum complexity of a holographic state is dual to the action of a certain spacetime region that we call a Wheeler-DeWitt patch. We illustrate and test the conjecture in the context of neutral, charged, and rotating black holes in anti-de Sitter spacetime, as well as black holes perturbed with static shells and with shock waves. This conjecture evolved from a previous conjecture that complexity is dual to spatial volume, but appears to be a major improvement over the original. In light of our results, we discuss the hypothesis that black holes are the fastest computers in nature.
Theta angle in holographic QCD
NASA Astrophysics Data System (ADS)
Järvinen, Matti
2017-03-01
V-QCD is a class of effective holographic models for QCD which fully includes the backreaction of quarks to gluon dynamics. The physics of the θ-angle and the axial anomaly can be consistently included in these models. We analyze their phase diagrams over ranges of values of the quark mass, Nf/Nc, and θ, computing observables such as the topological susceptibility and the meson masses. At small quark mass, where effective chiral Lagrangians are reliable, they agree with the predictions of V-QCD.
The holographic supersymmetric Casimir energy
NASA Astrophysics Data System (ADS)
Benetti Genolini, Pietro; Cassani, Davide; Martelli, Dario; Sparks, James
2017-01-01
We consider a general class of asymptotically locally AdS5 solutions of minimal gauged supergravity, which are dual to superconformal field theories on curved backgrounds S1×M3 preserving two supercharges. We demonstrate that standard holographic renormalization corresponds to a scheme that breaks supersymmetry. We propose new boundary terms that restore supersymmetry, and show that for smooth solutions with topology S1×R4 the improved on-shell action reproduces both the supersymmetric Casimir energy and the field theory supersymmetric relation between charges.
NASA Astrophysics Data System (ADS)
Mok, F.; Zhou, G.; Psaltis, D.
The most successful use of optical memories so far has been as read-only memories (ROM). A main reason for this success has been the availability of inexpensive methods to mass-produce copies of recorded disks. This has made it possible to publish data (audio, video, databases, computer games) and distribute it widely through normal retail channels. In this chapter, we show results of a holographic read-only memory (HROM) of which digital data on a master disk can be copied onto replicate disks efficiently.
Holographic superconductors with hyperscaling violation
NASA Astrophysics Data System (ADS)
Fan, ZhongYing
2013-09-01
We investigate holographic superconductors in asympototically geometries with hyperscaling violation. The mass of the scalar field decouples from the UV dimension of the dual scalar operator and can be chosen as negative as we want, without disturbing the Breitenlohner-Freedman bound. We first numerically find that the scalar condenses below a critical temperature and a gap opens in the real part of the conductivity, indicating the onset of superconductivity. We further analytically explore the effects of the hyperscaling violation on the superconducting transition temperature. We find that the critical temperature increases with the increasing of hyperscaling violation.
Multilayer Volume Holographic Optical Memory
NASA Technical Reports Server (NTRS)
Markov, Vladimir; Millerd, James; Trolinger, James; Norrie, Mark; Downie, John; Timucin, Dogan; Lau, Sonie (Technical Monitor)
1998-01-01
We demonstrate a scheme for volume holographic storage based on the features of shift selectivity of a speckle reference wave hologram. The proposed recording method allows more efficient use of the recording medium and increases the storage density in comparison with spherical or plane-wave reference beams. Experimental results of multiple hologram storage and replay in a photorefractive crystal of iron-doped lithium niobate are presented. The mechanism of lateral and longitudinal shift selectivity are described theoretically and shown to agree with experimental measurements.
Yeom, Han-Ju; Kim, Hee-Jae; Kim, Seong-Bok; Zhang, HuiJun; Li, BoNi; Ji, Yeong-Min; Kim, Sang-Hoo; Park, Jae-Hyeung
2015-12-14
We propose a bar-type three-dimensional holographic head mounted display using two holographic optical elements. Conventional stereoscopic head mounted displays may suffer from eye fatigue because the images presented to each eye are two-dimensional ones, which causes mismatch between the accommodation and vergence responses of the eye. The proposed holographic head mounted display delivers three-dimensional holographic images to each eye, removing the eye fatigue problem. In this paper, we discuss the configuration of the bar-type waveguide head mounted displays and analyze the aberration caused by the non-symmetric diffraction angle of the holographic optical elements which are used as input and output couplers. Pre-distortion of the hologram is also proposed in the paper to compensate the aberration. The experimental results show that proposed head mounted display can present three-dimensional see-through holographic images to each eye with correct focus cues.
Moving through a multiplex holographic scene
NASA Astrophysics Data System (ADS)
Mrongovius, Martina
2013-02-01
This paper explores how movement can be used as a compositional element in installations of multiplex holograms. My holographic images are created from montages of hand-held video and photo-sequences. These spatially dynamic compositions are visually complex but anchored to landmarks and hints of the capturing process - such as the appearance of the photographer's shadow - to establish a sense of connection to the holographic scene. Moving around in front of the hologram, the viewer animates the holographic scene. A perception of motion then results from the viewer's bodily awareness of physical motion and the visual reading of dynamics within the scene or movement of perspective through a virtual suggestion of space. By linking and transforming the physical motion of the viewer with the visual animation, the viewer's bodily awareness - including proprioception, balance and orientation - play into the holographic composition. How multiplex holography can be a tool for exploring coupled, cross-referenced and transformed perceptions of movement is demonstrated with a number of holographic image installations. Through this process I expanded my creative composition practice to consider how dynamic and spatial scenes can be conveyed through the fragmented view of a multiplex hologram. This body of work was developed through an installation art practice and was the basis of my recently completed doctoral thesis: 'The Emergent Holographic Scene — compositions of movement and affect using multiplex holographic images'.
Liu Molin; Gui Yuanxing; Liu Hongya
2008-12-15
In this paper, we study the quantum statistical entropy in a 5D Ricci-flat black string solution, which contains a 4D Schwarzschild-de Sitter black hole on the brane, by using the improved thin-layer method with the generalized uncertainty principle. The entropy is the linear sum of the areas of the event horizon and the cosmological horizon without any cutoff and any constraint on the bulk's configuration rather than the usual uncertainty principle. The system's density of state and free energy are convergent in the neighborhood of horizon. The small-mass approximation is determined by the asymptotic behavior of metric function near horizons. Meanwhile, we obtain the minimal length of the position {delta}x, which is restrained by the surface gravities and the thickness of layer near horizons.
Order parameter fluctuations in the holographic superconductor
NASA Astrophysics Data System (ADS)
Plantz, N. W. M.; Stoof, H. T. C.; Vandoren, S.
2017-03-01
We investigate the effect of order parameter fluctuations in the holographic superconductor. In particular, following an introduction to the concept of intrinsic dynamics and its implementation within holographic models, we compute the intrinsic spectral functions of the order parameter in both the normal and the superconducting phase, using a fully backreacted bulk geometry. We also present a vector-like large-N version of the Ginzburg–Landau model that accurately describes our long-wavelength results in both phases. Our results indicate that the holographic superconductor describes a relativistic multi-component superfluid in the universal regime of the BEC–BCS crossover.
LDA optical setup using holographic imaging configuration
NASA Astrophysics Data System (ADS)
Ghosh, Abhijit; Nirala, A. K.
2015-11-01
This paper describes one of the possible ways for improving fringe quality at LDA measuring volume using a holographic imaging configuration consisting of a single hololens. For its comparative study with a conventional imaging configuration, a complete characterization of fringes formed at the measurement volume by both the configuration is presented. Results indicate the qualitative as well as quantitative improvement of the fringes formed at measurement volume by the holographic imaging configuration. Hence it is concluded that use of holographic imaging configuration for making LDA optical setup is a better choice than the conventional one.
Fidelity susceptibility as holographic PV-criticality
NASA Astrophysics Data System (ADS)
Momeni, Davood; Faizal, Mir; Myrzakulov, Kairat; Myrzakulov, Ratbay
2017-02-01
It is well known that entropy can be used to holographically establish a connection among geometry, thermodynamics and information theory. In this paper, we will use complexity to holographically establish a connection among geometry, thermodynamics and information theory. Thus, we will analyze the relation among holographic complexity, fidelity susceptibility, and thermodynamics in extended phase space. We will demonstrate that fidelity susceptibility (which is the informational complexity dual to a maximum volume in AdS) can be related to the thermodynamical volume (which is conjugate to the cosmological constant in the extended thermodynamic phase space). Thus, this letter establishes a relation among geometry, thermodynamics, and information theory, using complexity.
Bit Threads and Holographic Entanglement
NASA Astrophysics Data System (ADS)
Freedman, Michael; Headrick, Matthew
2017-05-01
The Ryu-Takayanagi (RT) formula relates the entanglement entropy of a region in a holographic theory to the area of a corresponding bulk minimal surface. Using the max flow-min cut principle, a theorem from network theory, we rewrite the RT formula in a way that does not make reference to the minimal surface. Instead, we invoke the notion of a "flow", defined as a divergenceless norm-bounded vector field, or equivalently a set of Planck-thickness "bit threads". The entanglement entropy of a boundary region is given by the maximum flux out of it of any flow, or equivalently the maximum number of bit threads that can emanate from it. The threads thus represent entanglement between points on the boundary, and naturally implement the holographic principle. As we explain, this new picture clarifies several conceptual puzzles surrounding the RT formula. We give flow-based proofs of strong subadditivity and related properties; unlike the ones based on minimal surfaces, these proofs correspond in a transparent manner to the properties' information-theoretic meanings. We also briefly discuss certain technical advantages that the flows offer over minimal surfaces. In a mathematical appendix, we review the max flow-min cut theorem on networks and on Riemannian manifolds, and prove in the network case that the set of max flows varies Lipshitz continuously in the network parameters.
Holographic opto-fluidic microscopy.
Bishara, Waheb; Zhu, Hongying; Ozcan, Aydogan
2010-12-20
Over the last decade microfluidics has created a versatile platform that has significantly advanced the ways in which micro-scale organisms and objects are controlled, processed and investigated, by improving the cost, compactness and throughput aspects of analysis. Microfluidics has also expanded into optics to create reconfigurable and flexible optical devices such as reconfigurable lenses, lasers, waveguides, switches, and on-chip microscopes. Here we present a new opto-fluidic microscopy modality, i.e., Holographic Opto-fluidic Microscopy (HOM), based on lensless holographic imaging. This imaging modality complements the miniaturization provided by microfluidics and would allow the integration of microscopy into existing on-chip microfluidic devices with various functionalities. Our imaging modality utilizes partially coherent in-line holography and pixel super-resolution to create high-resolution amplitude and phase images of the objects flowing within micro-fluidic channels, which we demonstrate by imaging C. elegans, Giardia lamblia, and Mulberry pollen. HOM does not involve complicated fabrication processes or precise alignment, nor does it require a highly uniform flow of objects within microfluidic channels.
Exploring holographic Composite Higgs models
NASA Astrophysics Data System (ADS)
Croon, Djuna; Dillon, Barry M.; Huber, Stephan J.; Sanz, Veronica
2016-07-01
Simple Composite Higgs models predict new vector-like fermions not too far from the electroweak scale, yet LHC limits are now sensitive to the TeV scale. Motivated by this tension, we explore the holographic dual of the minimal model, MCHM5, to try and alleviate this tension without increasing the fine-tuning in the Higgs potential. Interestingly, we find that lowering the UV cutoff in the 5D picture allows for heavier top partners and less fine-tuning. In the 4D dual this corresponds to increasing the number of "colours" N , thus increasing the decay constant of the Goldstone Higgs. This is essentially a `Little Randall-Sundrum Model', which are known to reduce some flavour and electroweak constraints. Furthermore, in anticipation of the ongoing efforts at the LHC to put bounds on the top Yukawa, we demonstrate that deviations from the SM can be suppressed or enhanced with respect to what is expected from mere symmetry arguments in 4D. We conclude that the 5D holographic realisation of the MCHM5 with a small UV cutoff is not in tension with the current experimental data.
Bit Threads and Holographic Entanglement
NASA Astrophysics Data System (ADS)
Freedman, Michael; Headrick, Matthew
2016-11-01
The Ryu-Takayanagi (RT) formula relates the entanglement entropy of a region in a holographic theory to the area of a corresponding bulk minimal surface. Using the max flow-min cut principle, a theorem from network theory, we rewrite the RT formula in a way that does not make reference to the minimal surface. Instead, we invoke the notion of a "flow", defined as a divergenceless norm-bounded vector field, or equivalently a set of Planck-thickness "bit threads". The entanglement entropy of a boundary region is given by the maximum flux out of it of any flow, or equivalently the maximum number of bit threads that can emanate from it. The threads thus represent entanglement between points on the boundary, and naturally implement the holographic principle. As we explain, this new picture clarifies several conceptual puzzles surrounding the RT formula. We give flow-based proofs of strong subadditivity and related properties; unlike the ones based on minimal surfaces, these proofs correspond in a transparent manner to the properties' information-theoretic meanings. We also briefly discuss certain technical advantages that the flows offer over minimal surfaces. In a mathematical appendix, we review the max flow-min cut theorem on networks and on Riemannian manifolds, and prove in the network case that the set of max flows varies Lipshitz continuously in the network parameters.
Information Characteristics of Holographic and Laser Images
NASA Astrophysics Data System (ADS)
Malov, A. N.
2016-02-01
Physical principles of structural and informational analysis of coherent optical fields and processes of their digitization during imaging and transfer and recording of optical and holographic images are considered.
Holographic data storage using azobenzene polymer
NASA Astrophysics Data System (ADS)
Wang, Michael R.; Yang, Jianwen; Yan, Xingzhong; DeMasi, Ralph
2001-10-01
It is well known that holographic data storage can significantly increase data storage capacity. However, the technological maturity of holographic data storage is believed to be impeded by the lack of good holographic material that can be erased and recorded optically with almost unlimited rewriting cycles, large index modulation for large capacity multiplexed data recording, long lifetime, and immunity to destructive readout for archival applications. The performance of an azobenzene polymer is presented for holographic data storage applications. Initial experiments demonstrated that it is capable of satisfying many of above requirements. Recording of holograms without follow-up processing and being stable in application environment are its most attractive features. Applications of such material to other adaptive structures are possible.
Emergence in holographic scenarios for gravity
NASA Astrophysics Data System (ADS)
Dieks, Dennis; van Dongen, Jeroen; de Haro, Sebastian
2015-11-01
'Holographic' relations between theories have become an important theme in quantum gravity research. These relations entail that a theory without gravity is equivalent to a gravitational theory with an extra spatial dimension. The idea of holography was first proposed in 1993 by Gerard 't Hooft on the basis of his studies of evaporating black holes. Soon afterwards the holographic 'AdS/CFT' duality was introduced, which since has been intensively studied in the string theory community and beyond. Recently, Erik Verlinde has proposed that even Newton's law of gravitation can be related holographically to the 'thermodynamics of information' on screens. We discuss these scenarios, with special attention to the status of the holographic relation in them and to the question of whether they make gravity and spacetime emergent. We conclude that only Verlinde's scheme straightforwardly instantiates emergence. However, assuming a non-standard interpretation of AdS/CFT may create room for the emergence of spacetime and gravity there as well.
Hybrid holographic non-destructive test system
NASA Technical Reports Server (NTRS)
Kurtz, R. L. (Inventor)
1978-01-01
An automatic hybrid holographic non-destructive testing (HNDT) method and system capable of detecting flaws or debonds contained within certain materials are described. This system incorporates the techniques of optical holography, acoustical/optical holography and holographic correlation in determining the structural integrity of a test object. An automatic processing system including a detector and automatic data processor is used in conjunction with the three holographic techniques for correlating and interpreting the information supplied by the non-destructive systems. The automatic system also includes a sensor which directly translates an optical data format produced by the holographic techniques into electrical signals and then transmits this information to a digital computer for indicating the structural properties of the test object. The computer interprets the data gathered and determines whether further testing is necessary as well as the format of this new testing procedure.
Modular digital holographic fringe data processing system
NASA Technical Reports Server (NTRS)
Downward, J. G.; Vavra, P. C.; Schebor, F. S.; Vest, C. M.
1985-01-01
A software architecture suitable for reducing holographic fringe data into useful engineering data is developed and tested. The results, along with a detailed description of the proposed architecture for a Modular Digital Fringe Analysis System, are presented.
Lensless Digital Holographic Microscopy for Life Detection
NASA Astrophysics Data System (ADS)
Serabyn, E.; Liewer, K.; Wallace, J. K.; Rider, S.; Lindensmith, C.; Nadeau, J.
2016-10-01
Microscopy capable of volume imaging can be used to search for microbial life on ocean worlds. Here we discuss our recent digital holographic microscope (DHM) systems, which provide micron-scale resolution in a very compact package.
Holographic QCD for H-dibaryon (uuddss)
NASA Astrophysics Data System (ADS)
Suganuma, Hideo; Matsumoto, Kohei
2017-03-01
The H-dibaryon (uuddss) is studied in holographic QCD for the first time. In holographic QCD, four-dimensional QCD, i.e., SU(Nc) gauge theory with chiral quarks, can be formulated with S1-compactified D4/D8/\\overline {{{D8}}} -brane system. In holographic QCD with large (Nc, all the baryons appear as topological chiral solitons of Nambu-Goldstone bosons and (axial) vector mesons, and the H-dibaryon can be described as an SO(3)-type topological soliton with B = 2. We derive the low-energy effective theory to describe the H-dibaryon in holographic QCD. The H-dibaryon mass is found to be twice of the B = 1 hedgehog-baryon mass, MH ≃ 2.00MB=1HH, and is estimated about 1.7GeV, which is smaller than mass of two nucleons (flavor-octet baryons), in the chiral limit.
Some applications of holographic interferometry in biomechanics
NASA Astrophysics Data System (ADS)
Ebbeni, Jean P. L.
1992-03-01
Holographic interferometry is well adapted for the determination of 2D strain fields in osseous structures. The knowledge of those strain fields is important for the understanding of structure behavior such as arthrosis.
Holographic Interferometry--A Laboratory Experiment.
ERIC Educational Resources Information Center
de Frutos, A. M.; de la Rosa, M. I.
1988-01-01
Explains the problem of analyzing a phase object, separating the contribution due to thickness variations and that due to refractive index variations. Discusses the design of an interferometer and some applications. Provides diagrams and pictures of holographic images. (YP)
Antihumidity dichromated gelatin holographic recording material
NASA Astrophysics Data System (ADS)
Guo, Lurong; Dai, Chaoming; Guo, Yongkang; Cai, Tiequan
1991-12-01
In this paper we present an antihumidity dichromated gelatin holographic recording material called AHDCG. It possesses the good optical performances of common dichromated gelatin (DCG). The holograms produced by this material, under common laboratory circumstances (RH > 80 usually), have been kept for more than one year without degradation in efficiency. The method of making this material, the surface structure, and its holographic properties are presented.
Holographic data processing methods for medical prognosis
NASA Astrophysics Data System (ADS)
Antonov, V. A.; Grosmann, M. H.; Kartavenko, V. I.; Larkin, A. I.; Trukhanov, K. A.
2015-10-01
The various methods of laser coherent photonic implementations of multiparametric classification are discussed in this paper. The holographic and optical data processing methods for medical application are considered. Inverse two-phase coding and analysis of light distribution in the correlation plane enables us to realize a number of algorithms: search for a precedent, Hamming distance measurement, Bayes probability algorithm, deterministic and ‘correspondence’ algorithms. The experimental holographic results for medicine prognosis are shown.
Digital holographic nondestructive testing of laminate composite
NASA Astrophysics Data System (ADS)
Karray, Mayssa; Christophe, Poilane; Gargouri, Mohamed; Picart, Pascal
2016-09-01
Optical digital holographic techniques can be used for nondestructive testing of materials. Digital holographic nondestructive testing essentially measures deformations on the surface of the object. However, there is sufficient sensitivity to detect subsurface and internal defects in metallic and composite specimens. We investigate and discuss the vibration analysis of laminated composite glass-epoxy using time averaging in digital Fresnel holography to visualize the modes of vibration and to test the integrity of the structures of studied materials.
The recent holographic material: Konica P7000
NASA Astrophysics Data System (ADS)
Iwasaki, Masashi; Kubota, Toshihiro; Watanabe, Masachika; Yamauchi, Tsuyoshi; Kumasawa, Tomoko; Ueda, Kenji
2006-02-01
A newly developed silver halide material, KONIKA MINOLTA OPTO P7000, was examined its holographic characteristics. The commercially available material, KONIKA P5600, is blue-green sensitive but the new P7000 shows enough sensitivity to red light for practical use. We recorded holograms with He-Ne laser light on P7000 plates and evaluated the holographic characteristics such as diffraction efficiency and reconstructed wavelength. The results are discussed comparing with those of former Agfa products.
Holographic Combiners for Head-Up Displays
1977-10-01
AFAL-TR-77 -110 S HOLOGRAPHIC COMBINERS FOR HEAD-UP DISPLAYS S Radar and Optics Division Environmental Research Institute of Michigan P.O. Box 8618...to 200. SECURITY CLASSIFICATION OF THIS PAGE(RWihen Data Entered) FOREWORD This report was prepared by the Radar and Optics Division of the...with fringes parallel to the surface......31 Figure 13. Raytrace through the F-4 HUD with a holographic combiner
Holographic Optical Elements as Scanning Lidar Telescopes
NASA Technical Reports Server (NTRS)
Schwemmer, Geary K.; Rallison, Richard D.; Wilkerson, Thomas D.; Guerra, David V.
2003-01-01
We have investigated and developed the use of holographic optical elements (HOE) and holographic transmission gratings for scanning lidar telescopes. By rotating a flat HOE in its own plane with the focal spot on the rotation axis, a very simple and compact conical scanning telescope is possible. We developed and tested transmission and reflection HOES for use with the first three harmonics of Nd:YAG lasers, and designed, built, and tested two lidar systems based on this technology.
NASA Technical Reports Server (NTRS)
2006-01-01
Dark spots (left) and 'fans' appear to scribble dusty hieroglyphics on top of the Martian south polar cap in two high-resolution Mars Global Surveyor, Mars Orbiter Camera images taken in southern spring. Each image is about 3-kilometers wide (2-miles).
Coherent Digital Holographic Adaptive Optics
NASA Astrophysics Data System (ADS)
Liu, Changgeng
A new type of adaptive optics (AO) based on the principles of digital holography (DH) is proposed and developed for the use in wide-field and confocal retinal imaging. Digital holographic adaptive optics (DHAO) dispenses with the wavefront sensor and wavefront corrector of the conventional AO system. DH is an emergent imaging technology that gives direct numerical access to the phase of the optical field, thus allowing precise control and manipulation of the optical field. Incorporation of DH in an ophthalmic imaging system can lead to versatile imaging capabilities at substantially reduced complexity and cost of the instrument. A typical conventional AO system includes several critical hardware pieces: spatial light modulator, lenslet array, and a second CCD camera in addition to the camera for imaging. The proposed DHAO system replaces these hardware components with numerical processing for wavefront measurement and compensation of aberration through the principles of DH. (Abstract shortened by UMI.).
Rotationally Invariant Holographic Tracking System
NASA Astrophysics Data System (ADS)
Lambert, James L.; Chao, Tien-Hsin; Gheen, Gregory; Johnston, Alan R.; Liu, Hua-Kuang
1989-06-01
A multi-channel holographic correlator has been constructed which can identify and track objects of a given shape across the input field independent of their in-plane rotation. This system, derived from the classic Vander Lugt correlator, incorporates a hololens to store an array of matched spatial filters (MSFs) on thermoplastic film. Each member of the MSF array is generated from a different incrementally rotated version of the training object. Rotational invariant tracking is achieved through superposition of the corresponding array of the correlations in the output plane. Real time tracking is accomplished by utilizing a liquid crystal light valve (LCLV) illuminated with a CRT to process video input signals. The system can be programmed to recognize different objects by recording the MSF array on re-usable thermoplastic film. Discussion of the system architecture and laboratory results are presented.
Survey of holographic security systems
NASA Astrophysics Data System (ADS)
Kontnik, Lewis T.; Lancaster, Ian M.
1990-04-01
The counterfeiting of products and financial instruments is a major problem throughout the world today. The dimensions of the problem are growing, accelerated by the expanding availability of production technologies to sophisticated counterfeiters and the increasing capabilities of these technologies. Various optical techniques, including holography, are beingused in efforts to mark authentic products and to distinguish them from copies. Industry is recognizing that the effectiveness of these techniques depends on such factors as the economics of the counterfeiting process and the distribution channels for the products involved, in addition to the performance of the particular optical security technologies used. This paper surveys the nature of the growing counterfeit market place and reviews the utility of holographic optical security systems. In particular, we review the use of holograms on credit cards and other products; and outline certain steps the holography industry should take to promote these application.
Difference Holographic Interferometry Of Light-Bulbs At Direct Transillumination
NASA Astrophysics Data System (ADS)
Gyimesi, F.; Fuzessy, Z.
1990-04-01
Difference holographic interferometry makes the direct interferometric comparison of two objects possible by using holographic illuminations. In the present paper the case of phase objects is investigated at direct transillumination.
Holographic data storage: rebirthing a commercialization effort
NASA Astrophysics Data System (ADS)
Anderson, Ken; Ayres, Mark; Sissom, Brad; Askham, Fred
2014-02-01
The realization of a commercial holographic data storage device has remained elusive for many decades. The most recent efforts were by InPhase Technologies between 2001 and 2009 resulting in 52 functioning prototypes capable of 300GB/disk and 20MB/s transfer rates. Despite being the world's first fully functional holographic drives, the primary competitor to holographic archive storage at that time, LTO, had already achieved 800GB and 120MB/in 2008; and by 2010, LTO had achieved 1.5TB and 140MB/s. This left InPhase at a competitive disadvantage to LTO archive solutions despite other strengths such as robustness, random access, and longer-term archive lifetime. Looking into the future, holographic data storage must be highly competitive with tape in three critical areas: cost/TB, capacity/footprint, and transfer rate. If this can be achieved, holographic data storage would become a superior solution given the low latencies and overall robustness to propel it into being the archive storage front-runner. New technology advancements by Akonia Holographics have enabled the potential for ultra-high capacity holographic storage devices that are capable of world record bit densities of over 2Tbit/in2, 200-300MB/s transfer rates, and a media cost less than $10/TB in the next 5 years. A demonstration platform based on these new advances has been designed and is currently being built by Akonia to progressively demonstrate bit densities of 2Tb/in2, 4Tb/in2, and 8Tb/in2 over the next year.
The Compact and Inexpensive "Arrowhead" Setup for Holographic Interferometry
ERIC Educational Resources Information Center
Ladera, Celso L.; Donoso, Guillermo
2011-01-01
Hologram recording and holographic interferometry are intrinsically sensitive to phase changes, and therefore both are easily perturbed by minuscule optical path perturbations. It is therefore very convenient to bank on holographic setups with a reduced number of optical components. Here we present a compact off-axis holographic setup that…
Peebles, P. James E.
2015-01-01
The evidence for the dark matter (DM) of the hot big bang cosmology is about as good as it gets in natural science. The exploration of its nature is now led by direct and indirect detection experiments, to be complemented by advances in the full range of cosmological tests, including judicious consideration of the rich phenomenology of galaxies. The results may confirm ideas about DM already under discussion. If we are lucky, we also will be surprised once again. PMID:24794526
Holographic fluorescence microscopy with incoherent digital holographic adaptive optics.
Jang, Changwon; Kim, Jonghyun; Clark, David C; Lee, Seungjae; Lee, Byoungho; Kim, Myung K
2015-01-01
Introduction of adaptive optics technology into astronomy and ophthalmology has made great contributions in these fields, allowing one to recover images blurred by atmospheric turbulence or aberrations of the eye. Similar adaptive optics improvement in microscopic imaging is also of interest to researchers using various techniques. Current technology of adaptive optics typically contains three key elements: a wavefront sensor, wavefront corrector, and controller. These hardware elements tend to be bulky, expensive, and limited in resolution, involving, for example, lenslet arrays for sensing or multiactuator deformable mirrors for correcting. We have previously introduced an alternate approach based on unique capabilities of digital holography, namely direct access to the phase profile of an optical field and the ability to numerically manipulate the phase profile. We have also demonstrated that direct access and compensation of the phase profile are possible not only with conventional coherent digital holography, but also with a new type of digital holography using incoherent light: selfinterference incoherent digital holography (SIDH). The SIDH generates a complex—i.e., amplitude plus phase—hologram from one or several interferograms acquired with incoherent light, such as LEDs, lamps, sunlight, or fluorescence. The complex point spread function can be measured using guide star illumination and it allows deterministic deconvolution of the full-field image. We present experimental demonstration of aberration compensation in holographic fluorescence microscopy using SIDH. Adaptive optics by SIDH provides new tools for improved cellular fluorescence microscopy through intact tissue layers or other types of aberrant media.
Holographic fluorescence microscopy with incoherent digital holographic adaptive optics
NASA Astrophysics Data System (ADS)
Jang, Changwon; Kim, Jonghyun; Clark, David C.; Lee, Seungjae; Lee, Byoungho; Kim, Myung K.
2015-11-01
Introduction of adaptive optics technology into astronomy and ophthalmology has made great contributions in these fields, allowing one to recover images blurred by atmospheric turbulence or aberrations of the eye. Similar adaptive optics improvement in microscopic imaging is also of interest to researchers using various techniques. Current technology of adaptive optics typically contains three key elements: a wavefront sensor, wavefront corrector, and controller. These hardware elements tend to be bulky, expensive, and limited in resolution, involving, for example, lenslet arrays for sensing or multiactuator deformable mirrors for correcting. We have previously introduced an alternate approach based on unique capabilities of digital holography, namely direct access to the phase profile of an optical field and the ability to numerically manipulate the phase profile. We have also demonstrated that direct access and compensation of the phase profile are possible not only with conventional coherent digital holography, but also with a new type of digital holography using incoherent light: selfinterference incoherent digital holography (SIDH). The SIDH generates a complex-i.e., amplitude plus phase-hologram from one or several interferograms acquired with incoherent light, such as LEDs, lamps, sunlight, or fluorescence. The complex point spread function can be measured using guide star illumination and it allows deterministic deconvolution of the full-field image. We present experimental demonstration of aberration compensation in holographic fluorescence microscopy using SIDH. Adaptive optics by SIDH provides new tools for improved cellular fluorescence microscopy through intact tissue layers or other types of aberrant media.
Gambaro, G; Feltrin, G P; Lupo, A; Bonfante, L; D'Angelo, A; Antonello, A
2006-02-01
The introduction of radiological contrast media and intravenous (i.v.) urography in clinical diagnostics in the 1930s enabled the discovery of several diseases, including the medullary sponge kidney (MSK). MSK is a renal malformation characterized by cystic anomalies of precalyceal ducts, which is frequently associated with nephrocalcinosis and renal stones. Although it was first recognized by G Lenarduzzi in 1939, its thorough description was the result of the ante litteram multidisciplinary cooperation between a radiologist (Lenarduzzi), a urologist (Cacchi), and a pathologist (Ricci), all at the Padua University Hospital. These authors 'established' the paradigm for its diagnosis that is still used today. I.v. urography is the gold standard for the diagnosis of MSK, but as the technique is used less and less, there is a concrete possibility of this renal condition being forgotten in the future. Although the pathogenesis of MSK has yet to be elucidated, its association with different malformative conditions supports the idea that it is a developmental disorder. Recent findings suggest that MSK may be the consequence of a disruption of the ureteral-bud/metanephric-blastema interface.
Holographic duality in nonlinear hyperbolic metamaterials
NASA Astrophysics Data System (ADS)
Smolyaninov, Igor I.
2014-07-01
According to the holographic principle, the description of a volume of space can be thought of as encoded on its boundary. Holographic principle establishes equivalence, or duality, between theoretical description of volume physics, which involves gravity, and the gravity-free field theory, which describes physics on its surface. While generally accepted as a theoretical framework, so far there was no known experimental system which would exhibit explicit holographic duality and be amenable to direct experimental testing. Here we demonstrate that nonlinear optics of hyperbolic metamaterials admits such a dual holographic description. Wave equation which describes propagation of extraordinary light through the volume of metamaterial exhibits 2 + 1 dimensional Lorentz symmetry. The role of time in the corresponding effective 3D Minkowski spacetime is played by the spatial coordinate aligned with the optical axis of the material. Nonlinear optical Kerr effect bends this spacetime resulting in effective gravitational interaction between extraordinary photons. On the other hand, a holographic dual theory may be formulated on the metamaterial surface, which describes its nonlinear optics via interaction of cylindrical surface plasmons possessing conserved charges proportional to their angular momenta. Potential implications of this duality for superconductivity of hyperbolic metamaterials are discussed.
The energy performance of prototype holographic glazings
NASA Astrophysics Data System (ADS)
Papamichael, K.; Beltran, L.; Furler, R.; Lee, E. S.; Selkowitz, S.; Rubin, M.
1993-02-01
We report on the simulation of the energy performance of prototype holographic glazings in commercial office buildings in a California climate. These prototype glazings, installed above conventional side windows, are designed to diffract the transmitted solar radiation and reflect it off the ceiling, providing adequate daylight illumination for typical office tasks up to 10m from the window. In this study, we experimentally determined a comprehensive set of solar-optical properties and characterized the contribution of the prototype holographic glazings to workplane illuminance in a scale model of a typical office space. We then used the scale model measurements to simulate the energy performance of the holographic glazings over the course of an entire year for four window orientations (North, East, South and West) for the inland Los Angeles climate, using the DOE-2.lD building energy analysis computer program. The results of our experimental analyses indicate that these prototype holographic glazings diffract only a small fraction of the incident light. The results of this study indicate that these prototype holographic glazings will not save energy in commercial office buildings. Their performance is very similar to that of clear glass, which, through side windows, cannot efficiently illuminate more than a 4-6 m depth of a building's perimeter, because the cooling penalties due to solar heat gain are greater than the electric lighting savings due to daylighting.
NASA Astrophysics Data System (ADS)
Mazhari, N. S.; Momeni, Davood; Bahamonde, Sebastian; Faizal, Mir; Myrzakulov, Ratbay
2017-03-01
The holographic complexity and fidelity susceptibility have been defined as new quantities dual to different volumes in AdS. In this paper, we will use these new proposals to calculate both of these quantities for a variety of interesting deformations of AdS. We obtain the holographic complexity and fidelity susceptibility for an AdS black hole, Janus solution, a solution with cylindrical symmetry, an inhomogeneous background and a hyperscaling violating background. It is observed that the holographic complexity depends on the size of the subsystem for all these solutions and the fidelity susceptibility does not have any such dependence.
Holography and the virtual patient: the holographic medical image
NASA Astrophysics Data System (ADS)
Ko, Kathryn; Erickson, Ronald R.; Webster, John M.
1996-12-01
Practical holographic systems utilizing the pulsed laser are finding potential applications in medicine. Exploiting both the hologram's true 3D image and holographic interferometry these techniques enhance the physician's vision beyond the 2D radiological imaging of even the best CT and MRI. The authors describe the use of pulsed laser holography as applied to the morphological specialties: anatomy, pathology, and surgery. The authors report on the Holographic Brain Anatomy Atlas for medical education; pathologic documentation with holography, and the use of holographic interferometry in surgical planning. The techniques are outlined and a discussion on the interpretation of holographic interferometry with living subjects is provided.
Holographic maps of quasiparticle interference
NASA Astrophysics Data System (ADS)
Dalla Torre, Emanuele G.; He, Yang; Demler, Eugene
2016-11-01
The analysis of Fourier-transformed scanning tunnelling microscopy images with subatomic resolution is a common tool for studying the properties of quasiparticle excitations in strongly correlated materials. Although Fourier amplitudes are generally complex valued, earlier analysis primarily focused on their absolute values. Their complex phases were often deemed random, and thus irrelevant, due to the unknown positions of the impurities in the sample. Here we show how to factor out these random phases by analysing overlaps between Fourier amplitudes that differ by reciprocal lattice vectors. The resulting holographic maps provide important and previously unknown information about the electronic structures. When applied to superconducting cuprates, our method solves a long-standing puzzle of the dichotomy between equivalent wavevectors. We show that d-wave Wannier functions of the conduction band provide a natural explanation for experimental results that were interpreted as evidence for competing unconventional charge modulations. Our work opens a new pathway to identify the nature of electronic states in scanning tunnelling microscopy.
Theta dependence in holographic QCD
NASA Astrophysics Data System (ADS)
Bartolini, Lorenzo; Bigazzi, Francesco; Bolognesi, Stefano; Cotrone, Aldo L.; Manenti, Andrea
2017-02-01
We study the effects of the CP-breaking topological θ-term in the large N c QCD model by Witten, Sakai and Sugimoto with N f degenerate light flavors. We first compute the ground state energy density, the topological susceptibility and the masses of the lowest lying mesons, finding agreement with expectations from the QCD chiral effective action. Then, focusing on the N f = 2 case, we consider the baryonic sector and determine, to leading order in the small θ regime, the related holographic instantonic soliton solutions. We find that while the baryon spectrum does not receive O(θ ) corrections, this is not the case for observables like the electromagnetic form factor of the nucleons. In particular, it exhibits a dipole term, which turns out to be vector-meson dominated. The resulting neutron electric dipole moment, which is exactly the opposite as that of the proton, is of the same order of magnitude of previous estimates in the literature. Finally, we compute the CP-violating pion-nucleon coupling constant {overline{g}}_{π NN} , finding that it is zero to leading order in the large N c limit.
Linearity of holographic entanglement entropy
NASA Astrophysics Data System (ADS)
Almheiri, Ahmed; Dong, Xi; Swingle, Brian
2017-02-01
We consider the question of whether the leading contribution to the entanglement entropy in holographic CFTs is truly given by the expectation value of a linear operator as is suggested by the Ryu-Takayanagi formula. We investigate this property by computing the entanglement entropy, via the replica trick, in states dual to superpositions of macroscopically distinct geometries and find it consistent with evaluating the expectation value of the area operator within such states. However, we find that this fails once the number of semi-classical states in the superposition grows exponentially in the central charge of the CFT. Moreover, in certain such scenarios we find that the choice of surface on which to evaluate the area operator depends on the density matrix of the entire CFT. This nonlinearity is enforced in the bulk via the homology prescription of Ryu-Takayanagi. We thus conclude that the homology constraint is not a linear property in the CFT. We also discuss the existence of `entropy operators' in general systems with a large number of degrees of freedom.
Holographic confinement in inhomogeneous backgrounds
NASA Astrophysics Data System (ADS)
Marolf, Donald; Wien, Jason
2016-08-01
As noted by Witten, compactifying a d-dimensional holographic CFT on an S 1 gives a class of ( d - 1)-dimensional confining theories with gravity duals. The proto-typical bulk solution dual to the ground state is a double Wick rotation of the AdS d+1 Schwarzschild black hole known as the AdS soliton. We generalize such examples by allowing slow variations in the size of the S 1, and thus in the confinement scale. Coefficients governing the second order response of the system are computed for 3 ≤ d ≤ 8 using a derivative expansion closely related to the fluid-gravity correspondence. The primary physical results are that i) gauge-theory flux tubes tend to align orthogonal to gradients and along the eigenvector of the Hessian with the lowest eigenvalue, ii) flux tubes aligned orthogonal to gradients are attracted to gradients for d ≤ 6 but repelled by gradients for d ≥ 7, iii) flux tubes are repelled by regions where the second derivative along the tube is large and positive but are attracted to regions where the eigenvalues of the Hessian are large and positive in directions orthogonal to the tube, and iv) for d > 3, inhomogeneities act to raise the total energy of the confining vacuum above its zeroth order value.
Holographic entropy and Calabi's diastasis
NASA Astrophysics Data System (ADS)
D'Hoker, Eric; Gutperle, Michael
2014-10-01
The entanglement entropy for interfaces and junctions of two-dimensional CFTs is evaluated on holographically dual half-BPS solutions to six-dimensional Type 4b supergravity with m anti-symmetric tensor supermultiplets. It is shown that the moduli space for an N-junction solution projects to N points in the Kähler manifold SO(2 , m) / (SO(2) × SO( m)). For N =2 the interface entropy is expressed in terms of the central charge and Calabi's diastasis function on SO(2 , m) / (SO(2) × SO( m)), thereby lending support from holography to a proposal of Bachas, Brunner, Douglas, and Rastelli. For N =3, the entanglement entropy for a 3-junction decomposes into a sum of diastasis functions between pairs, weighed by combinations of the three central charges, provided the flux charges are all parallel to one another or, more generally, provided the space of flux charges is orthogonal to the space of unattracted scalars. Under similar assumptions for N ≥4, the entanglement entropy for the N -junction solves a variational problem whose data consist of the N central charges, and the diastasis function evaluated between pairs of N asymptotic AdS 3 × S 3 regions.
On effective holographic Mott insulators
NASA Astrophysics Data System (ADS)
Baggioli, Matteo; Pujolàs, Oriol
2016-12-01
We present a class of holographic models that behave effectively as prototypes of Mott insulators — materials where electron-electron interactions dominate transport phenomena. The main ingredient in the gravity dual is that the gauge-field dynamics contains self-interactions by way of a particular type of non-linear electrodynamics. The electrical response in these models exhibits typical features of Mott-like states: i) the low-temperature DC conductivity is unboundedly low; ii) metal-insulator transitions appear by varying various parameters; iii) for large enough self-interaction strength, the conductivity can even decrease with increasing doping (density of carriers) — which appears as a sharp manifestation of `traffic-jam'-like behaviour; iv) the insulating state becomes very unstable towards superconductivity at large enough doping. We exhibit some of the properties of the resulting insulator-superconductor transition, which is sensitive to the momentum dissipation rate in a specific way. These models imply a clear and generic correlation between Mott behaviour and significant effects in the nonlinear electrical response. We compute the nonlinear current-voltage curve in our model and find that indeed at large voltage the conductivity is largely reduced.
Brodsky, Stanley J.; de Teramond, Guy F.; /Costa Rica U.
2012-02-16
The relation between the hadronic short-distance constituent quark and gluon particle limit and the long-range confining domain is yet one of the most challenging aspects of particle physics due to the strong coupling nature of Quantum Chromodynamics, the fundamental theory of the strong interactions. The central question is how one can compute hadronic properties from first principles; i.e., directly from the QCD Lagrangian. The most successful theoretical approach thus far has been to quantize QCD on discrete lattices in Euclidean space-time. Lattice numerical results follow from computation of frame-dependent moments of distributions in Euclidean space and dynamical observables in Minkowski spacetime, such as the time-like hadronic form factors, are not amenable to Euclidean lattice computations. The Dyson-Schwinger methods have led to many important insights, such as the infrared fixed point behavior of the strong coupling constant, but in practice, the analyses are limited to ladder approximation in Landau gauge. Baryon spectroscopy and the excitation dynamics of nucleon resonances encoded in the nucleon transition form factors can provide fundamental insight into the strong-coupling dynamics of QCD. New theoretical tools are thus of primary interest for the interpretation of the results expected at the new mass scale and kinematic regions accessible to the JLab 12 GeV Upgrade Project. The AdS/CFT correspondence between gravity or string theory on a higher-dimensional anti-de Sitter (AdS) space and conformal field theories in physical space-time has led to a semiclassical approximation for strongly-coupled QCD, which provides physical insights into its nonperturbative dynamics. The correspondence is holographic in the sense that it determines a duality between theories in different number of space-time dimensions. This geometric approach leads in fact to a simple analytical and phenomenologically compelling nonperturbative approximation to the full light
Holographic optical elements as scanning lidar telescopes
NASA Astrophysics Data System (ADS)
Schwemmer, Geary K.; Rallison, Richard D.; Wilkerson, Thomas D.; Guerra, David V.
2006-09-01
We have developed and investigated the use of holographic optical elements (HOEs) and holographic transmission gratings for scanning lidar telescopes. Rotating a flat HOE in its own plane with the focal spot on the rotation axis makes a very simple and compact conical scanning telescope. We developed transmission and reflection HOEs for use at the first three harmonic wavelengths of Nd:YAG lasers. The diffraction efficiency, diffraction angle, focal length, focal spot size and optical losses were measured for several HOEs and holographic gratings, and found to be suitable for use as lidar receiver telescopes, and in many cases could also serve as the final collimating and beam steering optic for the laser transmitter. Two lidar systems based on this technology have been designed, built, and successfully tested in atmospheric science applications. This technology will enable future spaceborne lidar missions by significantly lowering the size, weight, power requirement and cost of a large aperture, narrow field of view scanning telescope.
High speed holographic cine-recorder
NASA Astrophysics Data System (ADS)
Snyder, Donald; Watts, David; Gordon, Joseph; Lysogorski, Charles; Powers, Aaron; Perry, John; Chenette, Eugene; Hudson, Roger; Young, Raymond
2005-08-01
Air Force Research Laboratory and North Dancer Labs researchers have completed the initial development and transition to operational use of a high-speed holographic movie system. This paper documents the first fully operational use of a novel and unique experimental capability for high-speed holographic movies and high-speed cinema interferometry. In this paper we document the initial experiments that were performed with the High Speed Holographic Recorder (HSHR) at the Munitions Directorate, Air Force Research Laboratory Site at Eglin, AFB, Florida. These experiments were performed to assess the possibilities for high-speed cine-laser holography combined with high-speed videography to document the formation and propagation of plumes of materials created by impact of high-speed projectiles. This paper details the development of the experimental procedures and initial results of this new tool. After successful integration and testing the system was delivered to Arnold Engineering Development Center.
Wavelength techniques for digital holographic memories
NASA Astrophysics Data System (ADS)
Lande, David
Holographic storage is a technique to store and retrieve information spread out in a volume, in contrast to current optical devices which store information locally on a surface. It provides for parallel page-by-page recording and readout of data instead of the usual serial, bit-by-bit, technique, and offers much higher diffraction-limited capacity. Success in the development of a competitive holographic storage device then depends on its cost, compactness and reliability. Since the first digital demonstrations, considerable effort by various groups has been spent in the development of high performance, practical holographic systems. This thesis presents several contributions toward this goal, suitable for holographic storage in lithium niobate and other applicable media. An intuitive explanation of volume holography is given, and Fourier analysis is used to derive the diffraction- limited capacity of digital storage in the form of elementary refractive index gratings. The physics of photorefractive materials, which are commonly used in holographic recording, is then presented, along with an established phenomenological model for grating formation. Following an analysis of imaging and multiplexing, a completely automated storage system implementing wavelength-multiplexed holography is described and evaluated, highlighting the feasibility of systems with fewer optical and mechanical components. The volatility of information in photorefractive media is then addressed by a demonstration of optical fixing, a technique based on two-photon recording mechanisms. Such an all-optical technique removes the need for heating elements, high voltages, or other post-processing elements currently used in non-volatile systems. Two-photon recording is also used to modulate, or apodize, the amplitude of volume gratings within the crystal bulk, providing a flexible technique to reduce cross-talk noise between stored pages and optimize the system capacity. Finally, simulations of
Simulating the energy performance of holographic glazings
NASA Astrophysics Data System (ADS)
Papamichael, K.; Beltran, L.; Furler, Reto; Lee, E. S.; Selkowitz, Steven E.; Rubin, Michael
1994-09-01
The light diffraction properties of holographic diffractive structures present an opportunity to improve the daylight performance in side-lit office spaces by redirecting and reflecting sunlight off the ceiling, providing adequate daylight illumination up to 30 ft (9.14 m) from the window wall. Prior studies of prototypical holographic glazings, installed above conventional `view' windows, have shown increased daylight levels over a deeper perimeter area than clear glass, for selected sun positions. In this study, we report on the simulation of the energy performance of prototypical holographic glazings assuming a commercial office building in the inland Los Angeles climate. The simulation of the energy performance involved determination of both luminous and thermal performance. Since the optical complexity of holographic glazings prevented the use of conventional algorithms for the simulation of their luminous performance, we used a newly developed method that combines experimentally determined directional workplane illuminance coefficients with computer-based analytical routines to determine a comprehensive set of daylight factors for many sun positions. These daylight factors were then used within the DOE-2.1D energy simulation program to determine hourly daylight and energy performance over the course of an entire year for four window orientations. Since the prototypical holographic diffractive structures considered in this study were applied on single pane clear glass, we also simulated the performance of hypothetical glazings, assuming the daylight performance of the prototype holographic glazings and the thermal performance of double-pane and low-e glazings. Finally, we addressed various design and implementation issues towards potential performance improvement.
Holographic fluorescence microscopy with incoherent digital holographic adaptive optics
NASA Astrophysics Data System (ADS)
Jang, Changwon; Kim, Jonghyun; Clark, David C.; Lee, Byoungho; Kim, Myung K.
2015-03-01
Introduction of adaptive optics technology into astronomy and ophthalmology has made great contributions in these fields, allowing one to recover images blurred by atmospheric turbulence or aberrations of the eye. Similar adaptive optics improvement in microscopic imaging is also of interest to researchers using various techniques. Current technology of adaptive optics typically contains three key elements: wavefront sensor, wavefront corrector and controller. These hardware elements tend to be bulky, expensive, and limited in resolution, involving, e.g., lenslet arrays for sensing or multi-acuator deformable mirrors for correcting. We have previously introduced an alternate approach to adaptive optics based on unique capabilities of digital holography, namely direct access to the phase profile of an optical field and the ability to numerically manipulate the phase profile. We have also demonstrated that direct access and compensation of the phase profile is possible not only with the conventional coherent type of digital holography, but also with a new type of digital holography using incoherent light: self-interference incoherent digital holography (SIDH). The SIDH generates complex - i.e. amplitude plus phase - hologram from one or several interferograms acquired with incoherent light, such as LEDs, lamps, sunlight, or fluorescence. The complex point spread function can be measured using a guide star illumination and it allows deterministic deconvolution of the full-field image. We present experimental demonstration of aberration compensation in holographic fluorescence microscopy using SIDH. The adaptive optics by SIDH provides new tools for improved cellular fluorescence microscopy through intact tissue layers or other types of aberrant media.
Real-time holographic surveillance system
Collins, H.D.; McMakin, D.L.; Hall, T.E.; Gribble, R.P.
1995-10-03
A holographic surveillance system is disclosed including means for generating electromagnetic waves; means for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; means for receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; means for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and means for displaying the processed information to determine nature of the target. The means for processing the electrical signals includes means for converting analog signals to digital signals followed by a computer means to apply a backward wave algorithm. 21 figs.
Real-time holographic surveillance system
Collins, H. Dale; McMakin, Douglas L.; Hall, Thomas E.; Gribble, R. Parks
1995-01-01
A holographic surveillance system including means for generating electromagnetic waves; means for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; means for receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; means for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and means for displaying the processed information to determine nature of the target. The means for processing the electrical signals includes means for converting analog signals to digital signals followed by a computer means to apply a backward wave algorithm.
Real-time wideband holographic surveillance system
Sheen, D.M.; Collins, H.D.; Hall, T.E.; McMakin, D.L.; Gribble, R.P.; Severtsen, R.H.; Prince, J.M.; Reid, L.D.
1996-09-17
A wideband holographic surveillance system including a transceiver for generating a plurality of electromagnetic waves; antenna for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; the transceiver also receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; a computer for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and a display for displaying the processed information to determine nature of the target. The computer has instructions to apply a three dimensional backward wave algorithm. 28 figs.
Real-time wideband holographic surveillance system
Sheen, David M.; Collins, H. Dale; Hall, Thomas E.; McMakin, Douglas L.; Gribble, R. Parks; Severtsen, Ronald H.; Prince, James M.; Reid, Larry D.
1996-01-01
A wideband holographic surveillance system including a transceiver for generating a plurality of electromagnetic waves; antenna for transmitting the electromagnetic waves toward a target at a plurality of predetermined positions in space; the transceiver also receiving and converting electromagnetic waves reflected from the target to electrical signals at a plurality of predetermined positions in space; a computer for processing the electrical signals to obtain signals corresponding to a holographic reconstruction of the target; and a display for displaying the processed information to determine nature of the target. The computer has instructions to apply a three dimensional backward wave algorithm.
Holographic Geometries for Condensed Matter Applications
NASA Astrophysics Data System (ADS)
Keränen, V.; Thorlacius, L.
2015-01-01
Holographic modeling of strongly correlated many-body systems motivates the study of novel spacetime geometries where the scaling behavior of quantum critical systems is encoded into spacetime symmetries. Einstein-Dilaton-Maxwell theory has planar black brane solutions that exhibit Lifshitz scaling and in some cases hyperscaling violation. Entanglement entropy and Wilson loops in the dual field theory are studied by inserting simple geometric probes involving minimal surfaces into the black brane geometry. Coupling to background matter fields leads to interesting low-energy behavior in holographic models, such as U(1) symmetry breaking and emergent Lifshitz scaling.
Improvement of image quality in holographic microscopy.
Budhiraja, C J; Som, S C
1981-05-15
A novel technique of noise reduction in holographic microscopy has been experimentally studied. It has been shown that significant improvement in the holomicroscopic images of actual low-contrast continuous tone biological objects can be achieved without trade off in image resolution. The technique makes use of holographically produced multidirectional phase gratings used as diffusers and the continuous addition of subchannel holograms. It has been shown that the self-imaging property of this type of diffuser makes the use of these diffusers ideal for microscopic objects. Experimental results have also been presented to demonstrate real-time image processing capability of this technique.
Holographic interferometry: A user`s guide
Griggs, D.
1993-10-01
This manual describes the procedures and components necessary to produce a holographic interferogram of a flow field in the Sandia National Laboratories hypersonic wind tunnel. In contrast to classical interferometry, holographic interferometry records the amplitude and phase distribution of a lightwave passing through the flow field at some instant of time. This information can then be reconstructed outside the wind tunnel for visual analysis and digital processing, yielding precise characterizations of aerodynamic phenomena. The reconstruction and subsequent hologram image storage process is discussed, with particular attention paid to the digital image processor and the data reduction technique.
Analysis and design of holographic solar concentrators
NASA Astrophysics Data System (ADS)
Kostuk, Raymond K.; Rosenberg, Glenn
2008-08-01
The diffraction and the dispersion properties of holographic optical elements are examined for use as solar concentrators for photovoltaic and hybrid photovoltaic/thermal energy conversion systems. The diffraction angle and efficiency are computed for folded optical geometries that are potentially useful for low concentration ratio systems that can reduce the cost of residential solar energy systems. An investigation of the collection efficiency of a holographic planar concentrator and a spectrum splitting concentrator are analyzed with different construction parameters. It is found that collection angles of 40o and spectral bandwidth of 70 nm result with folded optical geometries for single volume holograms.
Digital holographic Michelson interferometer for nanometrology
NASA Astrophysics Data System (ADS)
Sevrygin, Alexander A.; Korotkov, V. I.; Pulkin, S. A.; Tursunov, I. M.; Venediktov, D. V.; Venediktov, V. Yu.; Volkov, O. V.
2014-11-01
The paper considers the dynamic holographic interferometry schemes with amplification (multiplication) of holographic fringes and with correction for distortions, imposed by the interferometer scheme elements. The use of digital microscope and of the matrix light modulator with direct addressing provides the completely digital closed-loop performance of the overall system for real-time evaluation of nano-scale objects size. Considered schemes were verified in the laboratory experiment, using the Michelson micro-interferometer, equipped by the USB-microscope and digital holography stage, equipped by the Holoeye spatial light modulator.
Shape of mesons in holographic QCD
Torabian, Mahdi; Yee, Ho-Ung
2009-10-15
Based on the expectation that the constituent quark model may capture the right physics in the large N limit, we point out that the orbital angular momentum of the quark-antiquark pair inside light mesons of low spins in the constituent quark model may provide a clue for the holographic dual string model of large N QCD. Our discussion, relying on a few suggestive assumptions, leads to a necessity of world-sheet fermions in the bulk of dual strings that can incorporate intrinsic spins of fundamental QCD degrees of freedom. We also comment on the interesting issue of the size of mesons in holographic QCD.
Preparation and characterization hexoses for holographic recording
NASA Astrophysics Data System (ADS)
Mejias-Brizuela, Nildia Y.; Olivares-Pérez, A.
2016-03-01
Experimental technique is described for holographic record in two different hexoses, with a new photosensitizer, the ferric ammonium citrate, and compared to the hexoses-dichromated films. The ferric ammonium citrate is an optimal salt for photosensitization of hexoses because we obtained a diffraction efficiency to first order acceptable for saccharides materials (two and three percent), has ability for to storage information, holographic images are quite stable over time, it is hydrophobic and is cheap. The experiments showed that the films called hexose 1-citrate and hexose 1-dichromate, present the maximum diffraction efficiency at first diffraction order.
Model of holographic recording in thermoplastic materials.
Bányász, I
1998-04-10
A method for the evaluation of images reconstructed from holograms recorded in thermoplastic materials is reported. The method is based on the use of the experimental modulation transfer function and nonlinear holographic characteristics of the recording material. Calculations have been carried out for high-numerical-aperture holograms of a five-element Ronchi ruling. The quality of the reconstructed image as a function of the recording parameters has been computed. The model predicts that it is possible to optimize holographic recording in these materials.
Top-down holographic glueball decay rates
Brünner, F.; Parganlija, D.; Rebhan, A.
2016-01-22
We present new results on the decay patterns of scalar and tensor glueballs in the top-down holographic Witten-Sakai-Sugimoto model. This model, which has only one free dimensionless parameter, gives semi-quantitative predictions for the vector meson spectrum, their decay widths, and also a gluon condensate in agreement with SVZ sum rules. The holographic predictions for scalar glueball decay rates are compared with experimental data for the widely discussed gluon candidates f{sub 0}(1500) and f{sub 0}(1710)
Holographic display for see-through augmented reality using mirror-lens holographic optical element.
Li, Gang; Lee, Dukho; Jeong, Youngmo; Cho, Jaebum; Lee, Byoungho
2016-06-01
A holographic display system for realizing a three-dimensional optical see-through augmented reality (AR) is proposed. A multi-functional holographic optical element (HOE), which simultaneously performs the optical functions of a mirror and a lens, is adopted in the system. In the proposed method, a mirror that is used to guide the light source into a reflection type spatial light modulator (SLM) and a lens that functions as Fourier transforming optics are recorded on a single holographic recording material by utilizing an angular multiplexing technique of volume hologram. The HOE is transparent and performs the optical functions just for Bragg matched condition. Therefore, the real-world scenes that are usually distorted by a Fourier lens or an SLM in the conventional holographic display can be observed without visual disturbance by using the proposed mirror-lens HOE (MLHOE). Furthermore, to achieve an optimized optical recording condition of the MLHOE, the optical characteristics of the holographic material are measured. The proposed holographic AR display system is verified experimentally.
Padgett, Miles [University of Glasgow, Glasgow, Scotland
2016-07-12
Optical vortices and orbital angular momentum are currently topical subjects in the optics literature. Although seemingly esoteric, they are, in fact, the generic state of light and arise whenever three or more plane waves interfere. To be observed by eye the light must be monochromatic. Laser speckle is one such example, where the optical energy circulates around each black spot, giving a local orbital angular momentum. This talk with report three on-going studies. First, when considering a volume of interfering waves, the laser specs map out threads of complete darkness embedded in the light. Do these threads form loops? Links? Or even knots? Second, when looking through a rapidly spinning window, the image of the world on the other side is rotated: true or false? Finally, the entanglement of orbital angular momentum states means measuring how the angular position of one photons sets the angular momentum of another: is this an angular version of the EPR (Einstein, Podolsky, and Rosen) paradox?
Full-color holographic 3D printer
NASA Astrophysics Data System (ADS)
Takano, Masami; Shigeta, Hiroaki; Nishihara, Takashi; Yamaguchi, Masahiro; Takahashi, Susumu; Ohyama, Nagaaki; Kobayashi, Akihiko; Iwata, Fujio
2003-05-01
A holographic 3D printer is a system that produces a direct hologram with full-parallax information using the 3-dimensional data of a subject from a computer. In this paper, we present a proposal for the reproduction of full-color images with the holographic 3D printer. In order to realize the 3-dimensional color image, we selected the 3 laser wavelength colors of red (λ=633nm), green (λ=533nm), and blue (λ=442nm), and we built a one-step optical system using a projection system and a liquid crystal display. The 3-dimensional color image is obtained by synthesizing in a 2D array the multiple exposure with these 3 wavelengths made on each 250mm elementary hologram, and moving recording medium on a x-y stage. For the natural color reproduction in the holographic 3D printer, we take the approach of the digital processing technique based on the color management technology. The matching between the input and output colors is performed by investigating first, the relation between the gray level transmittance of the LCD and the diffraction efficiency of the hologram and second, by measuring the color displayed by the hologram to establish a correlation. In our first experimental results a non-linear functional relation for single and multiple exposure of the three components were found. These results are the first step in the realization of a natural color 3D image produced by the holographic color 3D printer.
Two color holographic interferometry for microgravity application
NASA Technical Reports Server (NTRS)
Trolinger, James D.; Weber, David C.
1995-01-01
Holographic interferometry is a primary candidate for determining temperature and concentration in crystal growth experiments designed for space. The method measures refractive index changes within the fluid of an experimental test cell resulting from temperature and/or concentration changes. When the refractive index changes are caused by simultaneous temperature and concentration changes, the contributions of the two effects cannot be separated by single wavelength interferometry. By using two wavelengths, however, two independent interferograms can provide the additional independent equation required to determine the two unknowns. There is no other technique available that provides this type of information. The primary objectives of this effort were to experimentally verify the mathematical theory of two color holographic interferometry (TCHI) and to determine the practical value of this technique for space application. In the foregoing study, the theory of TCHI has been tested experimentally over a range of interest for materials processing in space where measurements of temperature and concentration in a solution are required. New techniques were developed and applied to stretch the limits beyond what could be done with existing procedures. The study resulted in the production of one of the most advanced, enhanced sensitivity holographic interferometers in existence. The interferometric measurements made at MSFC represent what is believed to be the most accurate holographic interferometric measurements made in a fluid to date. The tests have provided an understanding of the limitations of the technique in practical use.
Pattern recognition with magnonic holographic memory device
Kozhevnikov, A.; Dudko, G.; Filimonov, Y.; Gertz, F.; Khitun, A.
2015-04-06
In this work, we present experimental data demonstrating the possibility of using magnonic holographic devices for pattern recognition. The prototype eight-terminal device consists of a magnetic matrix with micro-antennas placed on the periphery of the matrix to excite and detect spin waves. The principle of operation is based on the effect of spin wave interference, which is similar to the operation of optical holographic devices. Input information is encoded in the phases of the spin waves generated on the edges of the magnonic matrix, while the output corresponds to the amplitude of the inductive voltage produced by the interfering spin waves on the other side of the matrix. The level of the output voltage depends on the combination of the input phases as well as on the internal structure of the magnonic matrix. Experimental data collected for several magnonic matrixes show the unique output signatures in which maxima and minima correspond to specific input phase patterns. Potentially, magnonic holographic devices may provide a higher storage density compare to optical counterparts due to a shorter wavelength and compatibility with conventional electronic devices. The challenges and shortcoming of the magnonic holographic devices are also discussed.
Photorefractive phase-conjugation digital holographic microscopy
NASA Astrophysics Data System (ADS)
Chang, Chi-Ching; Chan, Huang-Tian; Shiu, Min-Tzung; Chew, Yang-Kun
2015-05-01
In this work, we propose an innovative method for digital holographic microscopy named as photorefractive phaseconjugation digital holographic microscopy (PPCDHM) technique based on the phase conjugation dynamic holographic process in photorefractive BaTiO3 crystal and the retrieval of phase and amplitude of the object wave were performed by a reflection-type digital holographic method. Both amplitude and phase reconstruction benefit from the prior amplification by self-pumped conjugation (SPPC) as they have an increased SNR. The interest of the PPCDHM is great, because its hologram is created by interfered the amplified phase-conjugate wave field generated from a photorefractive phase conjugator (PPC) correcting the phase aberration of the imaging system and the reference wave onto the digital CCD camera. Therefore, a precise three-dimensional description of the object with high SNR can be obtained digitally with only one hologram acquisition. The method requires the acquisition of a single hologram from which the phase distribution can be obtained simultaneously with distribution of intensity at the surface of the object.
Propagation phasor approach for holographic image reconstruction
Luo, Wei; Zhang, Yibo; Göröcs, Zoltán; Feizi, Alborz; Ozcan, Aydogan
2016-01-01
To achieve high-resolution and wide field-of-view, digital holographic imaging techniques need to tackle two major challenges: phase recovery and spatial undersampling. Previously, these challenges were separately addressed using phase retrieval and pixel super-resolution algorithms, which utilize the diversity of different imaging parameters. Although existing holographic imaging methods can achieve large space-bandwidth-products by performing pixel super-resolution and phase retrieval sequentially, they require large amounts of data, which might be a limitation in high-speed or cost-effective imaging applications. Here we report a propagation phasor approach, which for the first time combines phase retrieval and pixel super-resolution into a unified mathematical framework and enables the synthesis of new holographic image reconstruction methods with significantly improved data efficiency. In this approach, twin image and spatial aliasing signals, along with other digital artifacts, are interpreted as noise terms that are modulated by phasors that analytically depend on the lateral displacement between hologram and sensor planes, sample-to-sensor distance, wavelength, and the illumination angle. Compared to previous holographic reconstruction techniques, this new framework results in five- to seven-fold reduced number of raw measurements, while still achieving a competitive resolution and space-bandwidth-product. We also demonstrated the success of this approach by imaging biological specimens including Papanicolaou and blood smears. PMID:26964671
Laser-actuated holographic storage device
NASA Technical Reports Server (NTRS)
Gange, R. A.; Nagle, E. M.; Steinmetz, C. C.
1973-01-01
Device permits automatic selection of one out of thousands of pages in holographic memory system by using laser beam. In typical operation for 2 to 3 C temperature interval, using dc power supply with no power regulation, holograms were successfully written and erased over 2- by 2-cm area, using 80-mW argon laser beam.
Liquid crystals for holographic optical data storage.
Matharu, Avtar S; Jeeva, Shehzad; Ramanujam, P S
2007-12-01
A tutorial review is presented to inform and inspire the reader to develop and integrate strong scientific links between liquid crystals and holographic data storage, from a materials scientist's viewpoint. The principle of holographic data storage as a means of providing a solution to the information storage demands of the 21st century is detailed. Holography is a small subset of the much larger field of optical data storage and similarly, the diversity of materials used for optical data storage is enormous. The theory of polarisation holography which produces holograms of constant intensity, is discussed. Polymeric liquid crystals play an important role in the development of materials for holographic storage and photoresponsive materials based on azobenzene are targeted for discussion due to their ease of photo-reversion between trans- and cis-states. Although the final polymer may not be liquid crystalline, irradiation can induce ordered domains. The mesogens act in a co-operative manner, enhancing refractive indices and birefringences. Surface relief gratings are discussed as a consequence of holographic storage. Cholesteric polymers comprising azobenzene are briefly highlighted. Irradiation causing cis-trans-isomerisation can be used to control helix pitch. A brief mention of liquid crystals is also made since these materials may be of future interest since they are optically transparent and amenable to photo-induced anisotropy.
Holographic reflection gratings in photopolymerizable solgel materials.
Murciano, A; Blaya, S; Carretero, L; Madrigal, R F; Fimia, A
2006-08-01
The recording of holographic reflection gratings with a spatial frequency higher than 5400 lines/mm in photopolymerizable solgel materials is experimentally demonstrated. Diffraction efficiencies near 60% and a FWHM of 2.5 nm centered at 531.5 nm are achieved. Moreover, the effect of the energetic exposure is characterized at different recording intensities.
A holographic model for black hole complementarity
NASA Astrophysics Data System (ADS)
Lowe, David A.; Thorlacius, Larus
2016-12-01
We explore a version of black hole complementarity, where an approximate semiclassical effective field theory for interior infalling degrees of freedom emerges holo-graphically from an exact evolution of exterior degrees of freedom. The infalling degrees of freedom have a complementary description in terms of outgoing Hawking radiation and must eventually decohere with respect to the exterior Hamiltonian, leading to a breakdown of the semiclassical description for an infaller. Trace distance is used to quantify the difference between the complementary time evolutions, and to define a decoherence time. We propose a dictionary where the evolution with respect to the bulk effective Hamiltonian corresponds to mean field evolution in the holographic theory. In a particular model for the holographic theory, which exhibits fast scrambling, the decoherence time coincides with the scrambling time. The results support the hypothesis that decoherence of the infalling holographic state and disruptive bulk effects near the curvature singularity are comple-mentary descriptions of the same physics, which is an important step toward resolving the black hole information paradox.
Phases of kinky holographic nuclear matter
NASA Astrophysics Data System (ADS)
Elliot-Ripley, Matthew; Sutcliffe, Paul; Zamaklar, Marija
2016-10-01
Holographic QCD at finite baryon number density and zero temperature is studied within the five-dimensional Sakai-Sugimoto model. We introduce a new approximation that models a smeared crystal of solitonic baryons by assuming spatial homogeneity to obtain an effective kink theory in the holographic direction. The kink theory correctly reproduces a first order phase transition to lightly bound nuclear matter. As the density is further increased the kink splits into a pair of half-kink constituents, providing a concrete realization of the previously suggested dyonic salt phase, where the bulk soliton splits into constituents at high density. The kink model also captures the phenomenon of baryonic popcorn, in which a first order phase transition generates an additional soliton layer in the holographic direction. We find that this popcorn transition takes place at a density below the dyonic salt phase, making the latter energetically unfavourable. However, the kink model predicts only one pop, rather than the sequence of pops suggested by previous approximations. In the kink model the two layers produced by the single pop form the surface of a soliton bag that increases in size as the baryon chemical potential is increased. The interior of the bag is filled with abelian electric potential and the instanton charge density is localized on the surface of the bag. The soliton bag may provide a holographic description of a quarkyonic phase.
Gravitation from entanglement in holographic CFTs
NASA Astrophysics Data System (ADS)
Faulkner, Thomas; Guica, Monica; Hartman, Thomas; Myers, Robert C.; Van Raamsdonk, Mark
2014-03-01
Entanglement entropy obeys a `first law', an exact quantum generalization of the ordinary first law of thermodynamics. In any CFT with a semiclassical holographic dual, this first law has an interpretation in the dual gravitational theory as a constraint on the spacetimes dual to CFT states. For small perturbations around the CFT vacuum state, we show that the set of such constraints for all ball-shaped spatial regions in the CFT is exactly equivalent to the requirement that the dual geometry satisfy the gravitational equations of motion, linearized about pure AdS. For theories with entanglement entropy computed by the Ryu-Takayanagi formula S = /(4 G N), we obtain the linearized Einstein equations. For theories in which the vacuum entanglement entropy for a ball is computed by more general Wald functionals, we obtain the linearized equations for the associated higher-curvature theories. Using the first law, we also derive the holographic dictionary for the stress tensor, given the holographic formula for entanglement entropy. This method provides a simple alternative to holographic renormalization for computing the stress tensor expectation value in arbitrary higher derivative gravitational theories.
The Holographic Brain: Implications for Training Design.
ERIC Educational Resources Information Center
Jones, James R.
Without special training, most people predominantly process data in one of four ways. Few achieve a coveted whole brain state that integrates such important but separate brain functions as logic and intuition. With new training techniques that exploit the holographic properties of the brain, organizations may be able to tap powerful whole brain…
Pattern recognition with magnonic holographic memory device
NASA Astrophysics Data System (ADS)
Kozhevnikov, A.; Gertz, F.; Dudko, G.; Filimonov, Y.; Khitun, A.
2015-04-01
In this work, we present experimental data demonstrating the possibility of using magnonic holographic devices for pattern recognition. The prototype eight-terminal device consists of a magnetic matrix with micro-antennas placed on the periphery of the matrix to excite and detect spin waves. The principle of operation is based on the effect of spin wave interference, which is similar to the operation of optical holographic devices. Input information is encoded in the phases of the spin waves generated on the edges of the magnonic matrix, while the output corresponds to the amplitude of the inductive voltage produced by the interfering spin waves on the other side of the matrix. The level of the output voltage depends on the combination of the input phases as well as on the internal structure of the magnonic matrix. Experimental data collected for several magnonic matrixes show the unique output signatures in which maxima and minima correspond to specific input phase patterns. Potentially, magnonic holographic devices may provide a higher storage density compare to optical counterparts due to a shorter wavelength and compatibility with conventional electronic devices. The challenges and shortcoming of the magnonic holographic devices are also discussed.
Testing and inspecting lens by holographic means
Hildebrand, Bernard P.
1976-01-01
Processes for the accurate, rapid and inexpensive testing and inspecting of oncave and convex lens surfaces through holographic means requiring no beamsplitters, mirrors or overpower optics, and wherein a hologram formed in accordance with one aspect of the invention contains the entire interferometer and serves as both a master and illuminating source for both concave and said convex surfaces to be so tested.
Holographic Investigation of Solid Propellant Particulates.
1981-12-01
Science and Engineering Ii ABSTRACT This investigation completed the development process to establish a technique to obtain holographic recordings of...13 C. EXPERIMENTAL TECHNIQUE --------------------------------- 20 0. DISCUSSION...conditions (pressure, etc.) to the behavior of the particulates within the propellant port and through the nozzle. Four experimental techniques are being
Kunz, Martin; Liddle, Andrew R.; Parkinson, David; Gao Changjun
2009-10-15
Cosmological observations are normally fit under the assumption that the dark sector can be decomposed into dark matter and dark energy components. However, as long as the probes remain purely gravitational, there is no unique decomposition and observations can only constrain a single dark fluid; this is known as the dark degeneracy. We use observations to directly constrain this dark fluid in a model-independent way, demonstrating, in particular, that the data cannot be fit by a dark fluid with a single constant equation of state. Parametrizing the dark fluid equation of state by a variety of polynomials in the scale factor a, we use current kinematical data to constrain the parameters. While the simplest interpretation of the dark fluid remains that it is comprised of separate dark matter and cosmological constant contributions, our results cover other model types including unified dark energy/matter scenarios.
NASA Astrophysics Data System (ADS)
Wang, Chun-Xiao; Liu, Mo-Lin; Liu, Hong-Ya
2008-10-01
As one exact candidate of the higher dimensional black hole, the 5D Ricci Qat Schwarzschild-de Sitter black string space presents something interesting. In this paper, we give a numerical solution to the real scalar field around the Nariai black hole by the polynomial approximation. Unlike the previous tangent approximation, this fitting function makes a perfect match in the leading intermediate region and gives a good description near both the event and the cosmological horizons. We can read from our results that the wave is close to a harmonic one with the tortoise coordinate. Furthermore, with the actual radial coordinate the waves pile up almost equally near the both horizons.
High-aperture diffractive lens for holographic printer
NASA Astrophysics Data System (ADS)
Zherdev, A. Y.; Odinokov, S. B.; Lushnikov, D. S.; Shishova, M. V.; Gurylev, O. A.; Kaytukov, C. B.
2016-10-01
The optical scheme of holographic printer for obtaining of holographic stereograms with an increasing field of view is proposed. Conventional holographic printers allow obtaining holographic stereograms with the field of view up to 90°. Proposed scheme allows increasing field of view up to 120°. The optical scheme is based on a diffuser and a diffraction optical element, the high-aperture diffractive lens. The experience of using the composite holographic lens and the amplitude diffractive lens based on a binary Fresnel zone plate as a high-aperture diffractive lens is described. Samples of high-aperture diffractive lens with f-number f/0.3 are obtained and investigated. Samples of holographic stereograms are obtained using samples of high-aperture diffractive lens.
Review of volume holographic data storage
NASA Astrophysics Data System (ADS)
Hinkle, William P.
1997-07-01
We present a review of volume holographic memory technology highlighting the most important issues for the development of commercially viable mass data storage systems. To record data using volume holographic storage, data is encoded on a laser beam with a spatial light modulator (SLM). The object beam is directed into an optically sensitive material, typically a photorefractive crystal, and superimposed with a coherent reference beam, forming interference gratings. The material reacts to the interference pattern by spatial modulation of its optical absorption or refractive index. During data retrieval the reference beam alone illuminates the modulated region, causing diffraction of a beam that is modulated as if it were generated by the original object beam incident on the SLM; that is a duplicate of the original object beam. This beam is imaged onto a photodetector array for capture and decoding. Because the data are stored and retrieved as a 2D matrix, a volume holographic storage system is inherently parallel. Consequently, data is read many bits (conceivably in the range of megabits) at a time, so that this approach offers the potential of high data retrieval rates, on the order of tens of gigabits per second and access times of much less than a millisecond. Data recording speeds are very dependent on the choice of storage material and energy of the laser. System capacity and capability are a consequence of three major interrelated factors: (1) the time-energy requirement of the storage material and the permanence of the stored data; (2) the capacity and efficiency of the spatial light modulator; and (3) the laser's power, physical size, and coherence properties. When compared with traditional flat surface magnetic or optical storage, volume holographic data storage has the potential of advantageous capacity, speed, weight, power, and physical size. While these are attractive attributes, they are particularly useful for space applications. This paper presents
A Study of the H-dibaryon in Holographic QCD
NASA Astrophysics Data System (ADS)
Matsumoto, Kohei; Nakagawa, Yuya; Suganuma, Hideo
We study the H-dibaryon (uuddss) in holographic QCD for the first time. Holographic QCD is derived from a QCD-equivalent D-brane system (S1-compactified D4/D8/overline{D8}) in the superstring theory via the gauge/gravity correspondence. In holographic QCD, all baryons appear as topological chiral solitons of Nambu-Goldstone bosons and (axial) vector mesons. In this framework, the H-dibaryon can be described as an SO(3)-type hedgehog state. We present the formalism of the H-dibaryon in holographic QCD, and perform the calculation to investigate its properties in the chiral limit.
Lensless multispectral digital in-line holographic microscope
NASA Astrophysics Data System (ADS)
Ryle, James P.; McDonnell, Susan; Sheridan, John T.
2011-12-01
An compact multispectral digital in-line holographic microscope (DIHM) is developed that emulates Gabor's original holographic principle. Using sources of varying spatial coherence (laser, LED), holographic images of objects, including optical fiber, latex microspheres, and cancer cells, are successfully captured and numerically processed. Quantitative measurement of cell locations and percentage confluence are estimated, and pseudocolor images are also presented. Phase profiles of weakly scattering cells are obtained from the DIHM and are compared to those produced by a commercially available off-axis digital holographic microscope.
Lensless multispectral digital in-line holographic microscope.
Ryle, James P; McDonnell, Susan; Sheridan, John T
2011-12-01
An compact multispectral digital in-line holographic microscope (DIHM) is developed that emulates Gabor's original holographic principle. Using sources of varying spatial coherence (laser, LED), holographic images of objects, including optical fiber, latex microspheres, and cancer cells, are successfully captured and numerically processed. Quantitative measurement of cell locations and percentage confluence are estimated, and pseudocolor images are also presented. Phase profiles of weakly scattering cells are obtained from the DIHM and are compared to those produced by a commercially available off-axis digital holographic microscope.
Photosensitive holographic material with a medium of fluorescent ink
NASA Astrophysics Data System (ADS)
Olivares-Pérez, A.; Toxqui-López, S.; Fuentes-Tapia, I.; Ortiz-Gutiérrez, M.; Mellado-Villaseñor, G.
2012-03-01
Recent researches have been reported that is possible increase the diffraction efficiency parameter from holographic gratings when photosensitive material (PVA with ammonium dichromate) it is painted after register the hologram with commercial fluorescent ink. In this research we shown that PVA as a binder, with the fluorescent ink and ammonium dichromate, this mixed can be used as recording medium. We characterize this material by implementing holographic films in which holographic gratings are recorded with a He- Cd laser at 442nm, and measuring holographic parameters such as diffraction efficiency. We get increased the diffraction efficiency and also the lifetime of the film.
Jackson, M.A.
1990-01-01
Two separate studies are contained. The first study is concerned with approximations to cosmological spacetimes. The standard model of cosmology is based on the Friedman-Robertson-Walker spacetimes; these spacetimes are the spatially homogeneous and isotropic solutions of Einstein's equation. The idea of smoothing provides a framework for the use of Friedman-Robertson-Walker spacetimes as approximations to more realistic inhomogeneous spacetimes. An explicit smoothing procedure is examined which is based on smoothing initial data via the Ricci flow equation. The existence and convergence results are proved for the Ricci flows with initial data taken as the spatial three-metrics of certain Bianchi spacetimes and certain Gowdy spacetimes. The results allow consideration of the Bianchi and Gowdy spacetimes as testing grounds for this specific smoothing scheme. The second study pertains to the global existence problem in general relativity. Energy methods are known to be useful in global existence problem; the Bel-Robinson (BR) energy may play the role of an energy norm for general relativity. The evolution of the BR energy was studied in Gowdy T(sup 3) x R spacetimes. A quantity closely related to the BR energy decay monotonically as the spacetime evolves toward the final singularity, except in the special case of Kasner data, for which this quantity is constant.
HOMES Holographic Optical Method for Exoplanet Spectroscopy
NASA Astrophysics Data System (ADS)
Ditto, Thomas D.; McGrew, Stephen P.
2013-09-01
A novel telescope architecture is proposed specifically for the purpose of taking spectra of exoplanets orbiting stars within 10 pc ("the neighborhood"). The primary objective and the secondary spectrograph are holographic optical elements (HOEs) formed on flat membrane substrates of low areal mass that can be transported on cylinder rolls that are compatible with the payload geometry of delivery vehicles. Ribbon-shaped HOEs of up to 100 x 10 meters are contemplated. Computer models are presented with these dimensions. The models predict resolving power better than 10 mas. Because the primary separates wavelengths, we consider coronagraphs that use the divide and conquer strategy of one wavelength at a time. After delivery at the second Lagrange point, the stowed membranes are unfurled into flat holographic optics positioned in a four part formation spanning 1 km of open space.
Biometric identification using holographic radar imaging techniques
NASA Astrophysics Data System (ADS)
McMakin, Douglas L.; Sheen, David M.; Hall, Thomas E.; Kennedy, Mike O.; Foote, Harlen P.
2007-04-01
Pacific Northwest National Laboratory researchers have been at the forefront of developing innovative screening systems to enhance security and a novel imaging system to provide custom-fit clothing using holographic radar imaging techniques. First-of-a-kind cylindrical holographic imaging systems have been developed to screen people at security checkpoints for the detection of concealed, body worn, non-metallic threats such as plastic and liquid explosives, knifes and contraband. Another embodiment of this technology is capable of obtaining full sized body measurements in near real time without the person under surveillance removing their outer garments. Radar signals readily penetrate clothing and reflect off the water in skin. This full body measurement system is commercially available for best fitting ready to wear clothing, which was the first "biometric" application for this technology. One compelling feature of this technology for security biometric applications is that it can see effectively through disguises, appliances and body hair.
Development of 3D holographic endoscope
NASA Astrophysics Data System (ADS)
Özcan, Meriç; Önal Tayyar, Duygu
2016-03-01
Here we present the development of a 3D holographic endoscope with an interferometer built around a commercial rigid endoscope. We consider recording the holograms with coherent and incoherent light separately without compromising the white light imaging capacity of the endoscope. In coherent light based recording, reference wave required for the hologram is obtained in two different ways. First, as in the classical holography, splitting the laser beam before the object illumination, and secondly creating the reference beam from the object beam itself. This second method does not require path-length matching between the object wave and the reference wave, and it allows the usage of short coherence length light sources. For incoherent light based holographic recordings various interferometric configurations are considered. Experimental results on both illumination conditions are presented.
Reheating of the Universe as holographic thermalization
NASA Astrophysics Data System (ADS)
Kawai, Shinsuke; Nakayama, Yu
2016-08-01
Assuming gauge/gravity correspondence we study reheating of the Universe using its holographic dual. Inflaton decay and thermalisation of the decay products correspond to collapse of a spherical shell and formation of a blackhole in the dual anti-de Sitter (AdS) spacetime. The reheating temperature is computed as the Hawking temperature of the developed blackhole probed by a dynamical boundary, and is determined by the inflaton energy density and the AdS radius, with corrections from the dynamics of the shell collapse. For given initial energy density of the inflaton field the holographic model typically gives lower reheating temperature than the instant reheating scenario, while it is shown to be safely within phenomenological bounds.
Fast, compact, autonomous holographic adaptive optics.
Andersen, Geoff; Gelsinger-Austin, Paul; Gaddipati, Ravi; Gaddipati, Phani; Ghebremichael, Fassil
2014-04-21
We present a closed-loop adaptive optics system based on a holographic sensing method. The system uses a multiplexed holographic recording of the response functions of each actuator in a deformable mirror. By comparing the output intensity measured in a pair of photodiodes, the absolute phase can be measured over each actuator location. From this a feedback correction signal is applied to the input beam without need for a computer. The sensing and correction is applied to each actuator in parallel, so the bandwidth is independent of the number of actuator. We demonstrate a breadboard system using a 32-actuator MEMS deformable mirror capable of operating at over 10 kHz without a computer in the loop.
Note on zero temperature holographic superfluids
NASA Astrophysics Data System (ADS)
Guo, Minyong; Lan, Shanquan; Niu, Chao; Tian, Yu; Zhang, Hongbao
2016-06-01
In this note, we have addressed various issues on zero temperature holographic superfluids. First, inspired by our numerical evidence for the equality between the superfluid density and particle density, we provide an elegant analytic proof for this equality by a boost trick. Second, using not only the frequency domain analysis but also the time domain analysis from numerical relativity, we identify the hydrodynamic normal modes and calculate out the sound speed, which is shown to increase with the chemical potential and saturate to the value predicted by the conformal field theory in the large chemical potential limit. Third, the generic non-thermalization is demonstrated by the fully nonlinear time evolution from a non-equilibrium state for our zero temperature holographic superfluid. Furthermore, a conserved Noether charge is proposed in support of this behavior.
Biometric Identification Using Holographic Radar Imaging Techniques
McMakin, Douglas L.; Sheen, David M.; Hall, Thomas E.; Kennedy, Mike O.; Foote, Harlan P.
2007-04-01
Pacific Northwest National Laboratory researchers have been at the forefront of developing innovative screening systems to enhance security and a novel imaging system to provide custom-fit clothing using holographic radar imaging techniques. First-of-a-kind cylindrical holographic imaging systems have been developed to screen people at security checkpoints for the detection of concealed, body worn, non-metallic threats such as plastic and liquid explosives, knifes and contraband. Another embodiment of this technology is capable of obtaining full sized body measurements in near real time without the person under surveillance removing their outer garments. Radar signals readily penetrate clothing and reflect off the water in skin. This full body measurement system is commercially available for best fitting ready to wear clothing, which was the first “biometric” application for this technology. One compelling feature of this technology for security biometric applications is that it can see effectively through disguises, appliances and body hair.
Holographic models and the QCD trace anomaly
Jose L. Goity, Roberto C. Trinchero
2012-08-01
Five dimensional dilaton models are considered as possible holographic duals of the pure gauge QCD vacuum. In the framework of these models, the QCD trace anomaly equation is considered. Each quantity appearing in that equation is computed by holographic means. Two exact solutions for different dilaton potentials corresponding to perturbative and non-perturbative {beta}-functions are studied. It is shown that in the perturbative case, where the {beta}-function is the QCD one at leading order, the resulting space is not asymptotically AdS. In the non-perturbative case, the model considered presents confinement of static quarks and leads to a non-vanishing gluon condensate, although it does not correspond to an asymptotically free theory. In both cases analyses based on the trace anomaly and on Wilson loops are carried out.
Holographic trace anomaly at finite temperature
NASA Astrophysics Data System (ADS)
Lee, Bum-Hoon; Nam, Siyoung; Park, Chanyong
2017-01-01
Using the holographic renormalization, we investigate the finite temperature and size effect to the energy-momentum tensor of the dual field theory and its renormalization group (RG) flow. Following the anti-de Sitter/conformal field theory correspondence, the dual field theory of the AdS space is well known to be a conformal field theory that has no nontrivial RG flow. Holographically, that theory can be lifted to a finite temperature version by considering a AdS black hole solution. Because the black hole horizon associated with temperature is dimensionful, it breaks the boundary conformal symmetry and leads to a nontrivial RG flow. In this work, we investigate the finite temperature and size correction to a strongly interacting conformal field theory along the Wisonian renormalization group flow.
Holographic Optical Storage Using Photorefractive Polymers
NASA Technical Reports Server (NTRS)
Hayden, L. Michael; Strutz, Shane J.; Harris, Kristi; Ayachitula, Rajani
2000-01-01
The task for this report is to perform the basic research and develop a prototype benchtop holographic optical storage system based on photochromic and/or photorefractive polymers so that both permanent and erasable images may be stored and retrieved in the same mixed polymer medium. The task consist of: assembly and setup of the benchtop holographic storage system, including lasers, optics, and other ancillary equipment in a laboratory setting; and research and development of a suitable polymer matrix that will allow practical storage and retrieval of digital data. This will necessitate molecular design of the matrices involved and subsequent physics test to verify the characteristics of the matrices provide practical storage and retrieval.
Dynamics and observer dependence of holographic screens
NASA Astrophysics Data System (ADS)
Bousso, Raphael; Moosa, Mudassir
2017-02-01
We study the evolution of holographic screens, both generally and in explicit examples, including cosmology and gravitational collapse. A screen H consists of a one-parameter sequence of maximal surfaces called leaves. Its causal structure is nonrelativistic. Each leaf can store all of the quantum information on a corresponding null slice holographically at no more than one bit per Planck area. Therefore, we expect the screen geometry to reflect certain coarse-grained quantities in the quantum gravity theory. In a given spacetime, there are many different screens, which are naturally associated with different observers. We find that this ambiguity corresponds precisely to the free choice of a single function on H . We also consider the background-free construction of H , where the spacetime is not given. The evolution equations then constrain aspects of the full spacetime and the screen's embedding in it.
Holographic entanglement for Chern-Simons terms
NASA Astrophysics Data System (ADS)
Azeyanagi, Tatsuo; Loganayagam, R.; Ng, Gim Seng
2017-02-01
We derive the holographic entanglement entropy contribution from pure and mixed gravitational Chern-Simons(CS) terms in AdS2 k+1. This is done through two different methods: first, by a direct evaluation of CS action in a holographic replica geometry and second by a descent of Dong's derivation applied to the corresponding anomaly polynomial. In lower dimensions ( k = 1 , 2), the formula coincides with the Tachikawa formula for black hole entropy from gravitational CS terms. New extrinsic curvature corrections appear for k ≥ 3: we give explicit and concise expressions for the two pure gravitational CS terms in AdS7 and present various consistency checks, including agreements with the black hole entropy formula when evaluated at the bifurcation surface.
PVA glue as a recording holographic medium
NASA Astrophysics Data System (ADS)
Toxqui-López, S.; Olivares-Pérez, A.; Pinto-Iguanero, B.; Aguilar-Mora, A.; Fuentes-Tapia, I.
2012-03-01
PVA (Polyvinyl acetate ) glue is one of the most common forms of adhesive on the market, which is popular because it has an ability to adhere to many different surface, but besides in this research we shown that can be employed as polymeric matrix and is employed for holographic recording when this is doped with ammonium dichromate. Thin, uniform coating of this photopolymer is generated by gravity settling method. The drying time for the photosensitive layers is approximately 24 h. Therefore, we present the experimental results obtained through diffraction gratings were recorded using a laser of He-Cd (442 nm).Furthermore the average results of the diffraction efficiency parameter which is quantified by their two first orders of diffraction. The PVA glue with ammonium dichromate can be considered as versatile holographic recording media due to their good sensitivity low cost and self -developing.
Exploring unconventional capabilities of holographic tweezers
NASA Astrophysics Data System (ADS)
Hernandez, R. J.; Pagliusi, P.; Provenzano, C.; Cipparrone, G.
2011-06-01
We report an investigation of manipulation and trapping capabilities of polarization holographic tweezers. A polarization gradient connected with a modulation of the ellipticity shows an optical force related to the polarization of the light that can influence optically isotropic particles. While in the case of birefringent particles an unconventional trapping in circularly polarized fringes is observed. A liquid crystal emulsion has been adopted to investigate the capabilities of the holographic tweezers. The unusual trapping observed for rotating bipolar nematic droplets has suggested the involvement of the lift hydrodynamic force responsible of the Magnus effect, originating from the peculiar optical force field. We show that the Magnus force which is ignored in the common approach can contribute to unconventional optohydrodynamic trapping and manipulation.
Holographic Scaling and Dynamical Gauge Effects in Disordered Atomic Gases
NASA Astrophysics Data System (ADS)
Gemelke, Nathan
2016-05-01
Quantum systems with strong disorder, and those far from equilibrium or interacting with a thermal reservior, present unique challenges in a range of physical contexts, from non-relativistic condensed-matter settings, such as in study of localization phenomena, to relativistic cosmology and the study of fundamental interactions. Recently, two related concepts, that of the entropy of entanglement, and the controversial suggestion of entropic emergent gravity, have shed insight on several long-standing questions along these lines, suggesting that strongly disordered systems with causal barriers (either relativistic or those with Lieb-Robinson-like bounds) can be understood using holographic principles in combination with the equivalence between quantum vacuua thermal baths via the Unruh effect. I will discuss a range of experiments performed within a strong, topologically disordered medium for neutral atoms which simultaneously introduces quenched disorder for spin and mass transport, and provides simple mechanisms for open coupling to various types of dissipative baths. Under conditions in which a subset of quantum states are continuously decoupled from the thermal bath, dark state effects lead to slow light phenomena mimicking gravitational lensing in general relativity in a characterizable table-top disordered medium. Non-equilibrium steady-states are observed in direct analogy with the evaporation of gravitational singularities, and we observe scaling behaviors that can be directly connected to holographic measures of the information contained in disorder. Finally, I will show how a dynamic-gauge-field picture of this and similar systems can lead to a natural description of non-equilibrium and disordered phenomena, and how it provides some advantages over the Harris and Luck criteria for describing critical phenomena. Connections between out-of-equilibrium dynamics and some long-unresolved issues concerning the existence of a gauge-boson mass gap in certain Yang
Using a portable holographic camera in cosmetology
NASA Astrophysics Data System (ADS)
Bakanas, R.; Gudaitis, G. A.; Zacharovas, S. J.; Ratcliffe, D. B.; Hirsch, S.; Frey, S.; Thelen, A.; Ladrière, N.; Hering, P.
2006-07-01
The HSF-MINI portable holographic camera is used to record holograms of the human face. The recorded holograms are analyzed using a unique three-dimensional measurement system that provides topometric data of the face with resolution less than or equal to 0.5 mm. The main advantages of this method over other, more traditional methods (such as laser triangulation and phase-measurement triangulation) are discussed.
Holographic window for solar power generation
NASA Astrophysics Data System (ADS)
Kasezawa, Toshihiro; Horimai, Hideyoshi; Tabuchi, Hiroshi; Shimura, Tsutomu
2016-12-01
A new photovoltaic generation unit based on the application of holographic technologies called a Holo-Window is proposed in this work. The basic principle and the optical configuration used for the basic experimental unit are described. Suitable fabrication technology for a hologram with the broadband spectrum required to provide the appropriate sunlight capture capability is then discussed. Finally, a laboratory-prototype Holo-Window unit was developed and its performance was evaluated.
Holographic consequences of a no transmission principle
NASA Astrophysics Data System (ADS)
Engelhardt, Netta; Horowitz, Gary T.
2016-01-01
Two quantum field theories whose Hilbert spaces do not overlap cannot transmit a signal to one another. From this simple principle, we deduce some highly nontrivial consequences for holographic quantum gravity. These include: (i) certain cosmological bounces are forbidden, (ii) generic singularities inside black holes cannot be resolved, and (iii) traversable wormholes do not exist. At the classical level, this principle rules out certain types of naked singularities and suggests that new singularity theorems should exist.
Prehistory of holographic art: a personal view
NASA Astrophysics Data System (ADS)
Benyon, Margaret
1998-02-01
The history of art contains works by artists that may be seen as `holographic' in their aesthetic, philosophic and formal implications. This paper briefly explores some of these parallels, chosen for their interest as preholographic images. Examples are taken from works of Eastern and Western visionary art, works by individual artists such as Rembrandt and Marcel Duchamp, and from early 20th century art movements.
Some aspects of holographic W-gravity
NASA Astrophysics Data System (ADS)
Li, Wei; Theisen, Stefan
2015-08-01
We use the Chern-Simons formulation of higher spin theories in three dimensions to study aspects of holographic W-gravity. Concepts which were useful in studies of pure bulk gravity theories, such as the Fefferman-Graham gauge and the residual gauge transformations, which induce Weyl transformations in the boundary theory and their higher spin generalizations, are reformulated in the Chern-Simons language. Flat connections that correspond to conformal and lightcone gauges in the boundary theory are considered.
Holographic Airborne Rotating Lidar Instrument Experiment (HARLIE)
NASA Technical Reports Server (NTRS)
Schwemmer, Geary K.
1998-01-01
Scanning holographic lidar receivers are currently in use in two operational lidar systems, PHASERS (Prototype Holographic Atmospheric Scanner for Environmental Remote Sensing) and now HARLIE (Holographic Airborne Rotating Lidar Instrument Experiment). These systems are based on volume phase holograms made in dichromated gelatin (DCG) sandwiched between 2 layers of high quality float glass. They have demonstrated the practical application of this technology to compact scanning lidar systems at 532 and 1064 nm wavelengths, the ability to withstand moderately high laser power and energy loading, sufficient optical quality for most direct detection systems, overall efficiencies rivaling conventional receivers, and the stability to last several years under typical lidar system environments. Their size and weight are approximately half of similar performing scanning systems using reflective optics. The cost of holographic systems will eventually be lower than the reflective optical systems depending on their degree of commercialization. There are a number of applications that require or can greatly benefit from a scanning capability. Several of these are airborne systems, which either use focal plane scanning, as in the Laser Vegetation Imaging System or use primary aperture scanning, as in the Airborne Oceanographic Lidar or the Large Aperture Scanning Airborne Lidar. The latter class requires a large clear aperture opening or window in the aircraft. This type of system can greatly benefit from the use of scanning transmission holograms of the HARLIE type because the clear aperture required is only about 25% larger than the collecting aperture as opposed to 200-300% larger for scan angles of 45 degrees off nadir.
Fourier RGB synthetic aperture color holographic capture for wide angle holographic display
NASA Astrophysics Data System (ADS)
Gołoś, Anna; Zaperty, Weronika; Finke, Grzegorz; Makowski, Piotr; Kozacki, Tomasz
2016-09-01
In this work we present a high pixel count color holographic registration system that is designed to provide 3D holographic content of real-world large objects. Captured data is dedicated for holographic displays with a wide-viewing angle. The registration in color is realized by means of sequential recording with the use of three RGB laser light sources. The applied Fourier configuration of capture system gives large viewing angle and an optimal coverage of the detector resolution. Moreover, it enables to filter out zero order and twin image. In this work the captured Fourier holograms are transformed to general Fresnel type that is more suitable for 3D holographic displays. High resolution and large pixel count of holographic data and its spatial continuity is achieved through synthetic aperture concept with camera scanning and subpixel correlation based stitching. This grants an access to many tools of numerical hologram processing e.g. continuous viewing angle adjustment, and control of 3D image position and size. In this paper the properties of 1D synthetic aperture (60000 x 2500 pixels) are investigated. Each of the RGB 1D SA holograms is composed of 71 frames, which after stitching result in approx. 150 Megapixel hologram pixel count and 12° angular field of view. In experimental part high quality numerical reconstructions for each type of the hologram are shown. Moreover, the captured holograms are used for generation of hybrid hologram that is assembled from a set of RGB holograms of different color statues of height below 20 cm. In the final experiment this hybrid hologram as well as RGB hologram of a single object are reconstructed in the color holographic display.
Linder, Eric V.
2006-04-11
Non-negligible dark energy density at high redshifts would indicate dark energy physics distinct from a cosmological constant or"reasonable'" canonical scalar fields. Such dark energy can be constrained tightly through investigation of the growth of structure, with limits of<~;;2percent of total energy density at z>> 1 for many models. Intermediate dark energy can have effects distinct from its energy density; the dark ages acceleration can be constrained to last less than 5percent of a Hubble e-fold time, exacerbating the coincidence problem. Both the total linear growth, or equivalently sigma 8, and the shape and evolution of the nonlinear mass power spectrum for z<2 (using the Linder-White nonlinear mapping prescription) provide important windows. Probes of growth, such as weak gravitational lensing, can interact with supernovae and CMB distance measurements to scan dark energy behavior over the entire range z=0-1100.
Holographic Flow Visualization at NASA Langley
NASA Technical Reports Server (NTRS)
Burner, A. W.; Goad, W. K.
2005-01-01
Holographic flow visualization systems at two NASA Langley facilities, a hypersonic blow-down tunnel using CF4 gas and an expansion tube with very short test time, are described. A pulsed ruby laser is used at a CF4 tunnel for single pulse holography, double pulse with several minutes between exposures, and dual plate holographic interferometry. Shadow-graph, schlieren, and interferograms are reconstructed from the holograms in a separate reconstruction lab. At the expansion tube the short run time of 200 microseconds requires precise triggering of its double pulsed ruby laser. With pulse separation, one pulse can occur before and one after flow is established to obtain fringe free background interferograms (perfect infinite fringe) or both pulses can occur during flow in order to study flow instabilities. Holograms are reconstructed at the expansion tube with an in-place setup which makes use of a high power CW Argon laser and common optics for both recording and reconstructing the holograms. The holographic systems at the CF4 tunnel and expansion tube are operated routinely for flow visualization by tunnel technicians. Typical flow visualization photographs from both facilities are presented.
Magnonic holographic imaging of magnetic microstructures
NASA Astrophysics Data System (ADS)
Gutierrez, D.; Chiang, H.; Bhowmick, T.; Volodchenkov, A. D.; Ranjbar, M.; Liu, G.; Jiang, C.; Warren, C.; Khivintsev, Y.; Filimonov, Y.; Garay, J.; Lake, R.; Balandin, A. A.; Khitun, A.
2017-04-01
We propose and demonstrate a technique for magnetic microstructure imaging via their interaction with propagating spin waves. In this approach, the object of interest is placed on top of a magnetic testbed made of material with low spin wave damping. There are micro-antennas incorporated in the testbed. Two of these antennas are used for spin wave excitation while another one is used for the detecting of inductive voltage produced by the interfering spin waves. The measurements are repeated for different phase differences between the spin wave generating antennas which is equivalent to changing the angle of illumination. The collected data appear as a 3D plot - the holographic image of the object. We present experimental data showing magnonic holographic images of a low-coercivity Si/Co sample, a high-coercivity sample made of SrFe12O19 and a diamagnetic copper sample. We also present images of the three samples consisting of a different amount of SrFe12O19 powder. The imaging was accomplished on a Y3Fe2(FeO4)3 testbed at room temperature. The obtained data reveal the unique magnonic signatures of the objects. Experimental data is complemented by the results of numerical modeling, which qualitatively explain the characteristic features of the images. Potentially, magnonic holographic imaging may complement existing techniques and be utilized for non-destructive in-situ magnetic object characterization. The fundamental physical limits of this approach are also discussed.
Holographic disorder driven superconductor-metal transition
NASA Astrophysics Data System (ADS)
Areán, D.; Pando Zayas, L. A.; Landea, I. Salazar; Scardicchio, A.
2016-11-01
We implement the effects of disorder on a holographic superconductor by introducing a random chemical potential on the boundary. We demonstrate explicitly that increasing disorder leads to the formation of islands where the superconducting order is enhanced and subsequently to the transition to a metal. We study the behavior of the superfluid density and of the conductivity as a function of the strength of disorder. We find explanations for various marked features in the conductivities in terms of hydrodynamic quasinormal modes of the holographic superconductors. These identifications plus a particular disorder-dependent spectral weight shift in the conductivity point to a signature of the Higgs mode in the context of disordered holographic superconductors. We observe that the behavior of the order parameter close to the transition is not mean-field type as in the clean case; rather we find robust agreement with exp (-A |T -Tc|-ν), with ν =1.03 ±0.02 for this disorder-driven smeared transition.
A shape dynamical approach to holographic renormalization
NASA Astrophysics Data System (ADS)
Gomes, Henrique; Gryb, Sean; Koslowski, Tim; Mercati, Flavio; Smolin, Lee
2015-01-01
We provide a bottom-up argument to derive some known results from holographic renormalization using the classical bulk-bulk equivalence of General Relativity and Shape Dynamics, a theory with spatial conformal (Weyl) invariance. The purpose of this paper is twofold: (1) to advertise the simple classical mechanism, trading off gauge symmetries, that underlies the bulk-bulk equivalence of General Relativity and Shape Dynamics to readers interested in dualities of the type of AdS/conformal field theory (CFT); and (2) to highlight that this mechanism can be used to explain certain results of holographic renormalization, providing an alternative to the AdS/CFT conjecture for these cases. To make contact with the usual semiclassical AdS/CFT correspondence, we provide, in addition, a heuristic argument that makes it plausible that the classical equivalence between General Relativity and Shape Dynamics turns into a duality between radial evolution in gravity and the renormalization group flow of a CFT. We believe that Shape Dynamics provides a new perspective on gravity by giving conformal structure a primary role within the theory. It is hoped that this work provides the first steps toward understanding what this new perspective may be able to teach us about holographic dualities.
Holographic flow visualization at NASA Langley
NASA Technical Reports Server (NTRS)
Burner, A. W.; Goad, W. K.
1979-01-01
Holographic flow visualization systems at two NASA Langley facilities, a hypersonic blow-down tunnel using CF4 gas and an expansion tube with very short test time, are described. A pulsed ruby laser is used at a CF4 tunnel for single pulse holography, double pulse with several minutes between exposures, and dual plate holographic interferometry. Shadowgraph, schlieren, and interferograms are reconstructed from the holograms in a separate reconstruction lab. At the expansion tube the short run time of 200 microseconds requires precise triggering of its double pulsed ruby laser. With double pulse capability of 20 to 1200 microseconds pulse separation, one pulse can occur before and one later after flow is established to obtain fringe free background interferograms (perfect infinite fringe) or both pulses can occur during flow in order to study flow instabilities. Holograms are reconstructed at the expansion tube with an in-place setup which makes use of a high power CW Argon laser and common optics for both recording and reconstructing the holograms. The holographic systems at the CF4 tunnel and expansion tube are operated routinely for flow visualization by tunnel technicians. Typical flow visualization photographs from both facilities are presented.
Industrial and scientific applications of holographic measurements
NASA Astrophysics Data System (ADS)
Ginzburg, Vera M.
1997-05-01
The primary mission of the Holography Laboratory organized at the Opto-Physical Research Institute (YNIIOFI, Moscow, Russia) in 1966 was application of holography techniques in metrology [1]. The following basic tasks have been successfully accomplished [2-4]: (i) theoretical analysis of sources of measurement errors; (ii) development and batch production of optical holographic devices and reference instruments for their legal certification; (iii) development of methods and means for processing measurement data; specifically, the Radon transformation is applied for calculation of spatial distribution of refractive index in transparent objects; (iv) a method and device for stroboscopic measuring of 3D reconstructed images by a "periscope" technique; (v) utilization of holographic tomography and laser interferometry; (vi) instrumentation for microwave and ultrasonic holographometry, correlation-based techniques for rejection of imperfect products and for analysis ofpulsed signals. The developed holographic instrumentation has found widespread application at various scientific and industrial enterprises in the former Soviet Union and Eastern European countries. This report represents only a small selection of the total body of work accomplished in the laboratory.
Bottom-up holographic approach to QCD
Afonin, S. S.
2016-01-22
One of the most known result of the string theory consists in the idea that some strongly coupled gauge theories may have a dual description in terms of a higher dimensional weakly coupled gravitational theory — the so-called AdS/CFT correspondence or gauge/gravity correspondence. The attempts to apply this idea to the real QCD are often referred to as “holographic QCD” or “AdS/QCD approach”. One of directions in this field is to start from the real QCD and guess a tentative dual higher dimensional weakly coupled field model following the principles of gauge/gravity correspondence. The ensuing phenomenology can be then developed and compared with experimental data and with various theoretical results. Such a bottom-up holographic approach turned out to be unexpectedly successful in many cases. In the given short review, the technical aspects of the bottom-up holographic approach to QCD are explained placing the main emphasis on the soft wall model.
The techniques of holographic particle sizing
NASA Technical Reports Server (NTRS)
Kurtz, R. L.
1973-01-01
Depending on the mechanism of particle production, the resultant particle size and velocity distribution may range over several orders of magnitude. In general, if particle size information is desired from a given type generator, one must resort to some form of experimental determination of the distribution. If the source of particle production is a dynamic one involving a reasonable volume, holography provides a tailor-made particle size and velocity distribution detector. This is evidenced by the fact that holography allows the entire volume to be recorded on one exposure without any interference with the volume of interest. Herein lies a very important characteristic of the holographic particle detection technique: It provides a holographic nondestructive testing technique in the fullest sense of the definition of nondestructive testing. This report provides a description of three different systems useful in this technique and includes the experimental results from one of the holographic systems which was used to detect particle size and velocity distribution from the Skylab waste tank.
Two color holographic interferometry for microgravity application
NASA Technical Reports Server (NTRS)
Trolinger, James D.
1993-01-01
Holographic interferometry is a primary candidate for the measurement of temperature and concentration in various crystal growth experiments destined for space. The method measures refractive index changes in the experiment test cell. A refractive index change can be caused by concentration changes, temperature changes, or a combination of temperature and concentration changes. If the refractive index changes are caused by temperature and concentration changes occurring simultaneously in the experiment test cell, the contributions by the two effects cannot be separated by conventional measurement methods. By using two wavelengths, two independent interferograms can be produced from the reconstruction of the hologram. The two interferograms will be different due to dispersion properties of fluid materials. These differences provide the additional information that allows the separation of simultaneously occurring temperature and concentration gradients. There is no other technique available that can provide this type of information. The primary objectives of this effort are to experimentally verify the mathematical theory of two color holographic interferometry and to determine the practical value of this technique for space application. To achieve these objectives, the accuracy and sensitivity of the technique must be determined for geometry's and materials that are relevant to the Materials Processing in the Space program of NASA. This will be achieved through the use of a specially designed two-color holographic interferometry breadboard optical system. In addition to experiments to achieve the primary goals, the breadboard will also provide inputs to the design of an optimum space flight system.
Holographic interferometry for security and forensic applications
NASA Astrophysics Data System (ADS)
Ambadiyil, Sajan; R. C., Sreelekshmi; Mahadevan Pillai, V. P.; Prabhu, Radhakrishna
2016-10-01
Security holograms having unique 3D images are one of the tools for enhancing the security for product and personnel authentication and anti-counterfeiting. Apart from the high technology that is required, the uniqueness of a 3D object presents a significant additional threshold for the counterfeiting of such security holograms. But, due to the development of 3D printing technology, the hurdles are disabled and allow the chances of counterfeiting. In order to overcome this, holographic interferometry is effectively utilized and the object is recorded twice before and after the state of random object change. At the time of reconstruction, two signal waves generated simultaneously interfere each other, resulting in a fringe modulation. This fringe modulation in 3D image hologram with respect to the random object change is exploited to generate a rigid and unique anticounterfeit feature. Though holographic interferometry techniques are being widely used for the non-destructive evaluation, the applicability of this technology for the security and forensic activity is less exploited. This paper describes our efforts to introduce holographic interferometry in 3D image holograms for security and forensic applications.
Holographic Optical Elements as Scanning Lidar Telescopes
NASA Technical Reports Server (NTRS)
Schwemmer, Geary K.; Rallison, Richard D.; Wilkerson, Thomas D.; Guerra, David V.
2005-01-01
We have developed and investigated the use of holographic optical elements (HOEs) and holographic transmission gratings for scanning lidar telescopes. For example, rotating a flat HOE in its own plane with the focal spot on the rotation axis makes a very simple and compact conical scanning telescope. We developed and tested transmission and reflection HOEs for use at the first three harmonic wavelengths of Nd:YAG lasers. The diffraction efficiency, diffraction angle, focal length, focal spot size and optical losses were measured for several HOEs and holographic gratings, and found to be suitable for use as lidar receiver telescopes, and in many cases could also serve as the final collimating and beam steering optic for the laser transmitter. Two lidar systems based on this technology have been designed, built, and successfully tested in atmospheric science applications. This technology will enable future spaceborne lidar missions by significantly lowering the size, weight, power requirement and cost of a large aperture, narrow field of view scanning telescope.
Holographic sensors for diagnostics of solution components
Kraiskii, A V; Suitanov, T T; Postnikov, V A; Khamidulin, A V
2010-02-28
The properties of holographic sensors of two types are studied. The sensors are based on a three-dimensional polymer-network matrix of copolymers of acrylamide, acrylic acid (which are sensitive to the medium acidity and bivalent metal ions) and aminophenylboronic acid (sensitive to glucose). It is found that a change in the ionic composition of a solution results in changes in the distance between layers and in the diffraction efficiency of holograms. Variations in the shape of spectral lines, which are attributed to the inhomogeneity of a sensitive layer, and nonmonotonic changes in the emulsion thickness and diffraction efficiency were observed during transient processes. The composition of the components of a hydrogel medium is selected for systems which can be used as a base for glucose sensors with the mean holographic response in the region of physiological glucose concentration in model solutions achieving 40 nm/(mmol L{sup -1}). It is shown that the developed holographic sensors can be used for the visual and instrumental determination of the medium acidity, alcohol content, ionic strength, bivalent metal salts and the quality of water, in particular, for drinking. (laser applications and other topics in quantum electronics)
Gluonic effects on g-2: Holographic view
NASA Astrophysics Data System (ADS)
Kurachi, Masafumi; Matsuzaki, Shinya; Yamawaki, Koichi
2013-09-01
We study “gluonic effects” (gluon condensation effects) on the hadronic leading order (HLO) contributions to the anomalous magnetic moment (g-2) of leptons, based on a holographic model having explicit gluonic mode introduced for consistency with the operator product expansion of QCD. We find gluonic enhancement of HLO contributions to the muon g-2 by about 6%, which nicely fills in the gap between the holographic estimate without gluonic effects and the phenomenological one using the experimental data as inputs. Similar calculations including the gluonic effects for the electron and the tau lepton g-2 are also carried out in good agreement with the phenomenological estimates. We then apply our holographic estimate to the walking technicolor (WTC) where large technigluonic effects were shown to be vital for the technidilaton, (pseudo)Nambu-Goldstone boson of the (approximate) scale symmetry of WTC, to be naturally as light as 125 GeV. It is shown that the value of the techni-HLO contributions to the muon g-2 is 10-100 times enhanced by inclusion of the same amount of the gluonic effects as that realizing the 125 GeV technidilaton, although such an enhanced techni-HLO contribution is still negligibly small compared with the current deviation of the standard model prediction of the muon g-2 from the experiments. The techni-HLO contributions to the tau lepton g-2 is also discussed, suggesting a possible phenomenological relevance to be tested by the future experiments.
Compact scanning lidar systems using holographic optics
NASA Astrophysics Data System (ADS)
Schwemmer, Geary K.; Wilkerson, Thomas D.; Guerra, David
1998-08-01
Two scanning lidar systems have been built using holographic optical elements (HOE) that function as a scanning telescope primary optic. One is a ground based lidar using a reflection HOE, and uses a frequency doubled Nd:YAG laser transmitter. The other system is an airborne/ground based system that uses a transmission HOE and operates at the 1064 nm fundamental of the Nd:YAG laser. Each HOE has a focal spot on the center- line, normal to the flat disk holding the hologram, and a field of view (FOV) that points approximately 45 degrees from the normal. Rotating the disk effects a conical scan of the FOV. In both systems, the same HOE is also used to collimate and steer the transmitted laser beam. The utility of using the HOEs to save weight and size in scanning lidars is evidenced by the atmospheric backscatter data collected with these systems. They also will lower the cost of commercial systems due to the low cost of replicating HOEs and the simplified mechanical scanning systems. Development of airborne scanning lidar altimeters and other lidars and passive instruments using holographic optics are underway, including the development of a one meter diameter, space qualified holographic scanning telescope for use in the ultraviolet.
Drawing Lines with Light in Holographic Space
NASA Astrophysics Data System (ADS)
Chang, Yin-Ren; Richardson, Martin
2013-02-01
This paper explores the dynamic and expressive possibilities of holographic art through a comparison of art history and technical media such as photography, film and holographic technologies. Examples of modern art and creative expression of time and motions are examined using the early 20th century art movement, Cubism, where subjects are portrayed to be seen simultaneously from different angles. Folding space is represented as subject matter as it can depict space from multiple points of time. The paper also investigates the way holographic art has explored time and space. The lenticular lens-based media reveal a more subjective poetic art in the form of the lyrical images and messages as spectators pass through time, or walk along with the piece of work through an interactive process. It is argued that photographic practice is another example of artistic representation in the form of aesthetic medium of time movement and as such shares a common ground with other dynamic expression that require time based interaction.
Stereo multiplexed holographic particle image velocimeter
Adrian, R.J.; Barnhart, D.H.; Papen, G.A.
1996-08-20
A holographic particle image velocimeter employs stereoscopic recording of particle images, taken from two different perspectives and at two distinct points in time for each perspective, on a single holographic film plate. The different perspectives are provided by two optical assemblies, each including a collecting lens, a prism and a focusing lens. Collimated laser energy is pulsed through a fluid stream, with elements carried in the stream scattering light, some of which is collected by each collecting lens. The respective focusing lenses are configured to form images of the scattered light near the holographic plate. The particle images stored on the plate are reconstructed using the same optical assemblies employed in recording, by transferring the film plate and optical assemblies as a single integral unit to a reconstruction site. At the reconstruction site, reconstruction beams, phase conjugates of the reference beams used in recording the image, are directed to the plate, then selectively through either one of the optical assemblies, to form an image reflecting the chosen perspective at the two points in time. 13 figs.
Stereo multiplexed holographic particle image velocimeter
Adrian, Ronald J.; Barnhart, Donald H.; Papen, George A.
1996-01-01
A holographic particle image velocimeter employs stereoscopic recording of particle images, taken from two different perspectives and at two distinct points in time for each perspective, on a single holographic film plate. The different perspectives are provided by two optical assemblies, each including a collecting lens, a prism and a focusing lens. Collimated laser energy is pulsed through a fluid stream, with elements carried in the stream scattering light, some of which is collected by each collecting lens. The respective focusing lenses are configured to form images of the scattered light near the holographic plate. The particle images stored on the plate are reconstructed using the same optical assemblies employed in recording, by transferring the film plate and optical assemblies as a single integral unit to a reconstruction site. At the reconstruction site, reconstruction beams, phase conjugates of the reference beams used in recording the image, are directed to the plate, then selectively through either one of the optical assemblies, to form an image reflecting the chosen perspective at the two points in time.
NASA Astrophysics Data System (ADS)
Burner, A. W.; Goad, W. K.
1981-03-01
A technique of phase control during reconstruction of holographic interferograms is demonstrated in which the recorded scene beam with disturbance present is made to interfere with the real-time scene beam after the disturbance is removed. The reference phase is adjusted during reconstruction by manipulating either the scene or reference beams. Comparisons are made between the present technique and the two-reference-beam and two-plate techniques, more commonly used for phase control during reconstruction of holographic interferograms for flow visualization.
NASA Astrophysics Data System (ADS)
Bai, Yang; Schwaller, Pedro
2014-03-01
Most of the mass of ordinary matter has its origin from quantum chromodynamics (QCD). A similar strong dynamics, dark QCD, could exist to explain the mass origin of dark matter. Using infrared fixed points of the two gauge couplings, we provide a dynamical mechanism that relates the dark QCD confinement scale to our QCD scale, and hence provides an explanation for comparable dark baryon and proton masses. Together with a mechanism that generates equal amounts of dark baryon and ordinary baryon asymmetries in the early Universe, the similarity of dark matter and ordinary matter energy densities can be naturally explained. For a large class of gauge group representations, the particles charged under both QCD and dark QCD, necessary ingredients for generating the infrared fixed points, are found to have masses at 1-2 TeV, which sets the scale for dark matter direct detection and novel collider signatures involving visible and dark jets.
NASA Astrophysics Data System (ADS)
Co, Raymond T.; Harigaya, Keisuke; Nomura, Yasunori
2017-03-01
We present a simple and natural dark sector model in which dark matter particles arise as composite states of hidden strong dynamics and their stability is ensured by accidental symmetries. The model has only a few free parameters. In particular, the gauge symmetry of the model forbids the masses of dark quarks, and the confinement scale of the dynamics provides the unique mass scale of the model. The gauge group contains an Abelian symmetry U (1 )D , which couples the dark and standard model sectors through kinetic mixing. This model, despite its simple structure, has rich and distinctive phenomenology. In the case where the dark pion becomes massive due to U (1 )D quantum corrections, direct and indirect detection experiments can probe thermal relic dark matter which is generically a mixture of the dark pion and the dark baryon, and the Large Hadron Collider can discover the U (1 )D gauge boson. Alternatively, if the dark pion stays light due to a specific U (1 )D charge assignment of the dark quarks, then the dark pion constitutes dark radiation. The signal of this radiation is highly correlated with that of dark baryons in dark matter direct detection.
Secretly asymmetric dark matter
NASA Astrophysics Data System (ADS)
Agrawal, Prateek; Kilic, Can; Swaminathan, Sivaramakrishnan; Trendafilova, Cynthia
2017-01-01
We study a mechanism where the dark matter number density today arises from asymmetries generated in the dark sector in the early Universe, even though the total dark matter number remains zero throughout the history of the Universe. The dark matter population today can be completely symmetric, with annihilation rates above those expected from thermal weakly interacting massive particles. We give a simple example of this mechanism using a benchmark model of flavored dark matter. We discuss the experimental signatures of this setup, which arise mainly from the sector that annihilates the symmetric component of dark matter.
New large-format holographic laboratory in France
NASA Astrophysics Data System (ADS)
Gauchet, Pascal E. P.
1994-01-01
A new holographic laboratory, Photonics 3D, has opened in Lyon, France. Its objectives are many fold: to encourage creative research in the field of holographic imagery, to set up an artist in residence program and to allow the production of very large holograms.
Designing the Holographic Whole Language Program. Opinion Paper.
ERIC Educational Resources Information Center
Fluellen, Jerry
A paper describes how David Bohm's holographic world view can be used to design a whole language program. Characterized by interconnectedness and multidimensionality, Bohm's holographic paradigm joins Eastern and Western belief systems in an old fashion pursuit of wisdom, on the one hand, and a new fashion pursuit of solutions to nonlinear…
Holographic Wilson loops in anisotropic quark-gluon plasma.
NASA Astrophysics Data System (ADS)
Ageev, Dmitry
2016-10-01
The nonequilibrium properties of the anisotropic quark-gluon plasma are condidered from the holographic viewpoint. Lifshitz-like solution is considered as a holographic dual of anisotropic QGP. The black brane formation in such background is considered as a thermalization in dual theory. As a probe of thermalization we consider rectangular spatial Wilson loops with different orientation.
Holographic On-Line Learning Machine for Multicategory Classification
NASA Astrophysics Data System (ADS)
Paek, Eung Gi; Wullert, John R.; Patel, J. S.
1990-07-01
A holographic on-line learning machine that is capable of multicategory classification is described. The system exactly implements the single-layer perceptron algorithm in a fully parallel and analog fashion. The performance of the adaptive network is successfully tested for up to 24 characters with different scale and rotation. Also, a compact and robust version of the holographic learning machine is proposed.
Modal analysis of musical instruments with holographic interferometry
NASA Astrophysics Data System (ADS)
Rossing, Thomas D.; Hampton, D. Scott
1991-03-01
Holographic interferometry is a useful technique for studying the vibrational modes of both separate vibrating elements and complete instruments. Spatial resolution is excellent and studies can be made at small amplitudes. Time-average holographic interferograms of handbells Chinese two-tone bells Caribbean steel drums snare drum shells cymbals and guitars are shown. 1 .
Holographic instrumentation for monitoring crystal growth in space
NASA Technical Reports Server (NTRS)
Trolinger, James D.; Lal, Ravindra B.; Batra, Ashok K.
1990-01-01
Measurement requirements and candidates for measuring crystal growth in space are described, emphasizing holographic instrumentation. Existing instrumentation planned for the IML-1 Spaceflight is described along with advanced concepts for future application which incorporate diode lasers, fiber optics, and holographic optical elements. Particle image displacement velocimetry in crystal growth chambers is described.
Depth perception and user interface in digital holographic television
NASA Astrophysics Data System (ADS)
Barabas, James; Jolly, Sundeep; Smalley, Daniel E.; Bove, V. Michael, Jr.
2012-03-01
A holographic television system, featuring realtime incoherent 3D capture and live holographic display is used for experiments in depth perception. Holographic television has the potential to provide more complete visual representations, including latency-free motion parallax and more natural affordances for accommodation. Although this technology has potential to improve realism in many display applications, we investigate benefits in uses where direct vision of a workspace is not possible. Applications of this nature include work with hazardous materials, teleoperation over distance, and laparoscopic surgery. In this study, subjects perform manual 3D object manipulation tasks where they can only see the workspace through holographic closed-circuit television. This study is designed to compare performance at manual tasks using holographic television compared to performance with displays that mimic 2D, and stereoscopic television.
Optical properties of a photopolymer film for digital holographic storage
NASA Astrophysics Data System (ADS)
Shin, Changwon; Kim, Junghoi; Kim, Nam; Lee, Hyojin; Kim, Eunkyoung
2005-09-01
Tir- and mono functional monomers were dispersed in a solution of polysulfone in organic solvent containing a photo initiator and other additives. New photopolymer film was prepared by dispersing acrylic monomer in a polysulfone matrix. The Polysulfone was adopted as a binder since it affords transparent thick films with low dimensional changes during holographic recording. Optical property of the photopolymer showed high diffraction efficiency (>90%) under an optimized optical condition at 532nm laser. The angular selectivity for angular multiplexing page oriented holographic memories (POHMs), the maximum diffraction efficiency of the material during holographic recording, the diffraction efficiency of the films as a function of an incident angle of two beams, exposure energy for saturation of the holographic material and application for holographic data storage will be discussed.
Holographic illuminator for synchrotron-based projection lithography systems
Naulleau, Patrick P.
2005-08-09
The effective coherence of a synchrotron beam line can be tailored to projection lithography requirements by employing a moving holographic diffuser and a stationary low-cost spherical mirror. The invention is particularly suited for use in an illuminator device for an optical image processing system requiring partially coherent illumination. The illuminator includes: (1) a synchrotron source of coherent or partially coherent radiation which has an intrinsic coherence that is higher than the desired coherence, (2) a holographic diffuser having a surface that receives incident radiation from said source, (3) means for translating the surface of the holographic diffuser in two dimensions along a plane that is parallel to the surface of the holographic diffuser wherein the rate of the motion is fast relative to integration time of said image processing system; and (4) a condenser optic that re-images the surface of the holographic diffuser to the entrance plane of said image processing system.
Research on copying system of dynamic multiplex holographic stereograms
NASA Astrophysics Data System (ADS)
Fu, Huaiping; Yang, Hong; Zheng, Tong
2003-05-01
The most important advantage of holographic stereograms over conventional hologram is that they can produce 3D images at any desired scale with movement, holographers in many countries involved in the studies towards it. We began our works in the early 80's and accomplished two research projects automatic system for making synthetic holograms and multiplex synthetic rainbow holograms, Based on these works, a large scale holographic stereogram of an animated goldfish was made by us for practical advertisement. In order to meet the needs of the market, a copying system for making multiplex holographic stereograms, and a special kind of silver halide holographic film developed by us recently. The characteristic of the copying system and the property of the special silver-halide emulsion are introduced in this paper.
NASA Astrophysics Data System (ADS)
Kopp, Joachim; Liu, Jia; Slatyer, Tracy R.; Wang, Xiao-Ping; Xue, Wei
2016-12-01
We consider dark matter models in which the mass splitting between the dark matter particles and their annihilation products is tiny. Compared to the previously proposed Forbidden Dark Matter scenario, the mass splittings we consider are much smaller, and are allowed to be either positive or negative. To emphasize this modification, we dub our scenario "Impeded Dark Matter". We demonstrate that Impeded Dark Matter can be easily realized without requiring tuning of model parameters. For negative mass splitting, we demonstrate that the annihilation cross-section for Impeded Dark Matter depends linearly on the dark matter velocity or may even be kinematically forbidden, making this scenario almost insensitive to constraints from the cosmic microwave background and from observations of dwarf galaxies. Accordingly, it may be possible for Impeded Dark Matter to yield observable signals in clusters or the Galactic center, with no corresponding signal in dwarfs. For positive mass splitting, we show that the annihilation cross-section is suppressed by the small mass splitting, which helps light dark matter to survive increasingly stringent constraints from indirect searches. As specific realizations for Impeded Dark Matter, we introduce a model of vector dark matter from a hidden SU(2) sector, and a composite dark matter scenario based on a QCD-like dark sector.
DarkSide search for dark matter
Alexander, T.; Alton, D.; Arisaka, K.; Back, H. O.; Beltrame, P.; Benziger, J.; Bonfini, G.; Brigatti, A.; Brodsky, J.; Bussino, S.; Cadonati, L.; Calaprice, F.; Candela, A.; Cao, H.; Cavalcante, P.; Chepurnov, A.; Chidzik, S.; Cocco, A. G.; Condon, C.; D'Angelo, D.; Davini, S.; Vincenzi, M. De; Haas, E. De; Derbin, A.; Pietro, G. Di; Dratchnev, I.; Durben, D.; Empl, A.; Etenko, A.; Fan, A.; Fiorillo, G.; Franco, D.; Fomenko, K.; Forster, G.; Gabriele, F.; Galbiati, C.; Gazzana, S.; Ghiano, C.; Goretti, A.; Grandi, L.; Gromov, M.; Guan, M.; Guo, C.; Guray, G.; Hungerford, E. V.; Ianni, Al; Ianni, An; Joliet, C.; Kayunov, A.; Keeter, K.; Kendziora, C.; Kidner, S.; Klemmer, R.; Kobychev, V.; Koh, G.; Komor, M.; Korablev, D.; Korga, G.; Li, P.; Loer, B.; Lombardi, P.; Love, C.; Ludhova, L.; Luitz, S.; Lukyanchenko, L.; Lund, A.; Lung, K.; Ma, Y.; Machulin, I.; Mari, S.; Maricic, J.; Martoff, C. J.; Meregaglia, A.; Meroni, E.; Meyers, P.; Mohayai, T.; Montanari, D.; Montuschi, M.; Monzani, M. E.; Mosteiro, P.; Mount, B.; Muratova, V.; Nelson, A.; Nemtzow, A.; Nurakhov, N.; Orsini, M.; Ortica, F.; Pallavicini, M.; Pantic, E.; Parmeggiano, S.; Parsells, R.; Pelliccia, N.; Perasso, L.; Perasso, S.; Perfetto, F.; Pinsky, L.; Pocar, A.; Pordes, S.; Randle, K.; Ranucci, G.; Razeto, A.; Romani, A.; Rossi, B.; Rossi, N.; Rountree, S. D.; Saggese, P.; Saldanha, R.; Salvo, C.; Sands, W.; Seigar, M.; Semenov, D.; Shields, E.; Skorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Sukhotin, S.; Suvarov, Y.; Tartaglia, R.; Tatarowicz, J.; Testera, G.; Thompson, J.; Tonazzo, A.; Unzhakov, E.; Vogelaar, R. B.; Wang, H.; Westerdale, S.; Wojcik, M.; Wright, A.; Xu, J.; Yang, C.; Zavatarelli, S.; Zehfus, M.; Zhong, W.; Zuzel, G.
2013-11-22
The DarkSide staged program utilizes a two-phase time projection chamber (TPC) with liquid argon as the target material for the scattering of dark matter particles. Efficient background reduction is achieved using low radioactivity underground argon as well as several experimental handles such as pulse shape, ratio of ionization over scintillation signal, 3D event reconstruction, and active neutron and muon vetos. The DarkSide-10 prototype detector has proven high scintillation light yield, which is a particularly important parameter as it sets the energy threshold for the pulse shape discrimination technique. The DarkSide-50 detector system, currently in commissioning phase at the Gran Sasso Underground Laboratory, will reach a sensitivity to dark matter spin-independent scattering cross section of 10^{-45} cm^{2} within 3 years of operation.
Dror, Jeff Asaf; Kuflik, Eric; Ng, Wee Hao
2016-11-18
We propose a new mechanism for thermal dark matter freeze-out, called codecaying dark matter. Multicomponent dark sectors with degenerate particles and out-of-equilibrium decays can codecay to obtain the observed relic density. The dark matter density is exponentially depleted through the decay of nearly degenerate particles rather than from Boltzmann suppression. The relic abundance is set by the dark matter annihilation cross section, which is predicted to be boosted, and the decay rate of the dark sector particles. The mechanism is viable in a broad range of dark matter parameter space, with a robust prediction of an enhanced indirect detection signal. Finally, we present a simple model that realizes codecaying dark matter.
Kumar, Jason
2014-06-24
We review the theoretical framework underlying models of asymmetric dark matter, describe astrophysical constraints which arise from observations of neutron stars, and discuss the prospects for detecting asymmetric dark matter.
The dark side of cosmology: dark matter and dark energy.
Spergel, David N
2015-03-06
A simple model with only six parameters (the age of the universe, the density of atoms, the density of matter, the amplitude of the initial fluctuations, the scale dependence of this amplitude, and the epoch of first star formation) fits all of our cosmological data . Although simple, this standard model is strange. The model implies that most of the matter in our Galaxy is in the form of "dark matter," a new type of particle not yet detected in the laboratory, and most of the energy in the universe is in the form of "dark energy," energy associated with empty space. Both dark matter and dark energy require extensions to our current understanding of particle physics or point toward a breakdown of general relativity on cosmological scales.
An input-data page modulation scheme for content-addressable holographic digital data storage
NASA Astrophysics Data System (ADS)
John, Renu; Joseph, Joby; Singh, Kehar
2005-05-01
We implement a new modulation scheme for inputting digital data pages for content-addressable holographic data storage. This scheme, which is a modification of the hybrid ternary modulation (HTM) scheme, exploits the advantages of both pure phase modulation and hybrid ternary modulation. The technique of using binary phase data pages with equal number of 0 and π using twisted-nematic liquid crystal spatial light modulator reduces strong dc component and produces a more homogeneous spectral distribution at the recording plane. This technique should facilitate better recording of all spatial frequencies, and thus improve the discrimination capability of a content-addressable memory. In HTM, there are three states to represent binary bits, whereas in the proposed code, we use the two bright states with a difference of π for coding the binary data. The third state, which is a dark state, is used to code the undesired regions of the spatial light modulator (SLM) while performing a search operation using a small search argument. We also introduce a new balanced modulation code which is a modified version of the 8:12 modulation code to address the coding subtleties associated with phase-based data pages. The proposed technique enhances the discrimination capability of content search using small search arguments, thereby giving better results in associative recall in a holographic memory system, with very low number of false hits compared to the existing schemes. A comparative study is presented of discrimination ratio and SNR for the different modulation schemes.
From Planck Data to Planck Era: Observational Tests of Holographic Cosmology
NASA Astrophysics Data System (ADS)
Afshordi, Niayesh; Corianò, Claudio; Delle Rose, Luigi; Gould, Elizabeth; Skenderis, Kostas
2017-01-01
We test a class of holographic models for the very early Universe against cosmological observations and find that they are competitive to the standard cold dark matter model with a cosmological constant (Λ CDM ) of cosmology. These models are based on three-dimensional perturbative superrenormalizable quantum field theory (QFT), and, while they predict a different power spectrum from the standard power law used in Λ CDM , they still provide an excellent fit to the data (within their regime of validity). By comparing the Bayesian evidence for the models, we find that Λ CDM does a better job globally, while the holographic models provide a (marginally) better fit to the data without very low multipoles (i.e., l ≲30 ), where the QFT becomes nonperturbative. Observations can be used to exclude some QFT models, while we also find models satisfying all phenomenological constraints: The data rule out the dual theory being a Yang-Mills theory coupled to fermions only but allow for a Yang-Mills theory coupled to nonminimal scalars with quartic interactions. Lattice simulations of 3D QFTs can provide nonperturbative predictions for large-angle statistics of the cosmic microwave background and potentially explain its apparent anomalies.
From Planck Data to Planck Era: Observational Tests of Holographic Cosmology.
Afshordi, Niayesh; Corianò, Claudio; Delle Rose, Luigi; Gould, Elizabeth; Skenderis, Kostas
2017-01-27
We test a class of holographic models for the very early Universe against cosmological observations and find that they are competitive to the standard cold dark matter model with a cosmological constant (ΛCDM) of cosmology. These models are based on three-dimensional perturbative superrenormalizable quantum field theory (QFT), and, while they predict a different power spectrum from the standard power law used in ΛCDM, they still provide an excellent fit to the data (within their regime of validity). By comparing the Bayesian evidence for the models, we find that ΛCDM does a better job globally, while the holographic models provide a (marginally) better fit to the data without very low multipoles (i.e., l≲30), where the QFT becomes nonperturbative. Observations can be used to exclude some QFT models, while we also find models satisfying all phenomenological constraints: The data rule out the dual theory being a Yang-Mills theory coupled to fermions only but allow for a Yang-Mills theory coupled to nonminimal scalars with quartic interactions. Lattice simulations of 3D QFTs can provide nonperturbative predictions for large-angle statistics of the cosmic microwave background and potentially explain its apparent anomalies.
NASA Astrophysics Data System (ADS)
Petrov, Valery; Lau, Bernhard
1996-09-01
Quick, reliable and inexpensive testing of products and components is needed in industry more often than not. Holography due to its intrinsic limitations and reasonably high costs yet is a method which is used comparatively rarely for industrial optical inspections. In the Laboratory of Technical Optics, Laser Technologies and Optoelectronics we produce holograms and interferograms on silver halide media in extremely unpromising conditions intentionally introduced to fit industrial ones. The main features of our processes are: (1) high speed of the whole process of data acquisition, storage and final presentation; (2) possibility to perform all these operations in strong daylight corresponding to industrial illumination levels or even exceeding recommended levels of illumination of industrial working places; (3) possibility to avoid any dark rooms; (4) high diffraction efficiency of holograms measured at the wavelength of recording, i.e. any wavelength shifts of holographic reconstruction are avoided for any types of holograms including reflection ones usually suffering from such shifts; (5) low costs due to low labor and equipment costs; and (6) easiness of performing quick checks in industrial environment. In our experiments we investigated various optical setups for recording holograms, double exposure and real time interferograms, in situ among them, and different types of holographic optical elements. We used different types of lasers: helium-neon (633 nm), argon (488 nm), semiconductor (675 and 685 nm), ruby (693 nm). Various silver halide media were used: Agfa Gevaert 8 E 75 HD films and plates, Russian PFG-03 and PFG-03 C (color).
Freese, Katherine; Rindler-Daller, Tanja; Spolyar, Douglas; Valluri, Monica
2016-06-01
Dark stars are stellar objects made (almost entirely) of hydrogen and helium, but powered by the heat from dark matter annihilation, rather than by fusion. They are in hydrostatic and thermal equilibrium, but with an unusual power source. Weakly interacting massive particles (WIMPs), among the best candidates for dark matter, can be their own antimatter and can annihilate inside the star, thereby providing a heat source. Although dark matter constitutes only [Formula: see text]0.1% of the stellar mass, this amount is sufficient to power the star for millions to billions of years. Thus, the first phase of stellar evolution in the history of the Universe may have been dark stars. We review how dark stars come into existence, how they grow as long as dark matter fuel persists, and their stellar structure and evolution. The studies were done in two different ways, first assuming polytropic interiors and more recently using the MESA stellar evolution code; the basic results are the same. Dark stars are giant, puffy (∼10 AU) and cool (surface temperatures ∼10 000 K) objects. We follow the evolution of dark stars from their inception at ∼[Formula: see text] as they accrete mass from their surroundings to become supermassive stars, some even reaching masses >[Formula: see text] and luminosities >[Formula: see text], making them detectable with the upcoming James Webb Space Telescope. Once the dark matter runs out and the dark star dies, it may collapse to a black hole; thus dark stars may provide seeds for the supermassive black holes observed throughout the Universe and at early times. Other sites for dark star formation may exist in the Universe today in regions of high dark matter density such as the centers of galaxies. The current review briefly discusses dark stars existing today, but focuses on the early generation of dark stars.
Chamseddine, Ali H.; Mukhanov, Viatcheslav E-mail: viatcheslav.Mukhanov@lmu.de
2016-02-01
We modify Einstein General Relativity by adding non-dynamical scalar fields to account simultaneously for both dark matter and dark energy. The dark energy in this case can be distributed in-homogeneously even within horizon scales. Its inhomogeneities can contribute to the late time integrated Sachs-Wolfe effect, possibly removing some of the low multipole anomalies in the temperature fluctuations of the CMB spectrum. The presence of the inhomogeneous dark matter also influences structure formation in the universe.
NASA Astrophysics Data System (ADS)
Freese, Katherine; Rindler-Daller, Tanja; Spolyar, Douglas; Valluri, Monica
2016-06-01
Dark stars are stellar objects made (almost entirely) of hydrogen and helium, but powered by the heat from dark matter annihilation, rather than by fusion. They are in hydrostatic and thermal equilibrium, but with an unusual power source. Weakly interacting massive particles (WIMPs), among the best candidates for dark matter, can be their own antimatter and can annihilate inside the star, thereby providing a heat source. Although dark matter constitutes only ≲ 0.1% of the stellar mass, this amount is sufficient to power the star for millions to billions of years. Thus, the first phase of stellar evolution in the history of the Universe may have been dark stars. We review how dark stars come into existence, how they grow as long as dark matter fuel persists, and their stellar structure and evolution. The studies were done in two different ways, first assuming polytropic interiors and more recently using the MESA stellar evolution code; the basic results are the same. Dark stars are giant, puffy (˜10 AU) and cool (surface temperatures ˜10 000 K) objects. We follow the evolution of dark stars from their inception at ˜1{{M}⊙} as they accrete mass from their surroundings to become supermassive stars, some even reaching masses >{{10}6}{{M}⊙} and luminosities >{{10}10}{{L}⊙} , making them detectable with the upcoming James Webb Space Telescope. Once the dark matter runs out and the dark star dies, it may collapse to a black hole; thus dark stars may provide seeds for the supermassive black holes observed throughout the Universe and at early times. Other sites for dark star formation may exist in the Universe today in regions of high dark matter density such as the centers of galaxies. The current review briefly discusses dark stars existing today, but focuses on the early generation of dark stars.
Nonthermal Supermassive Dark Matter
NASA Technical Reports Server (NTRS)
Chung, Daniel J. H.; Kolb, Edward W.; Riotto, Antonio
1999-01-01
We discuss several cosmological production mechanisms for nonthermal supermassive dark matter and argue that dark matter may he elementary particles of mass much greater than the weak scale. Searches for dark matter should ma be limited to weakly interacting particles with mass of the order of the weak scale, but should extend into the supermassive range as well.
Traversable geometric dark energy wormholes constrained by astrophysical observations
NASA Astrophysics Data System (ADS)
Wang, Deng; Meng, Xin-he
2016-09-01
In this paper, we introduce the astrophysical observations into the wormhole research. We investigate the evolution behavior of the dark energy equation of state parameter ω by constraining the dark energy model, so that we can determine in which stage of the universe wormholes can exist by using the condition ω <-1. As a concrete instance, we study the Ricci dark energy (RDE) traversable wormholes constrained by astrophysical observations. Particularly, we find from Fig. 5 of this work, when the effective equation of state parameter ω _X<-1 (or z<0.109), i.e., the null energy condition (NEC) is violated clearly, the wormholes will exist (open). Subsequently, six specific solutions of statically and spherically symmetric traversable wormhole supported by the RDE fluids are obtained. Except for the case of a constant redshift function, where the solution is not only asymptotically flat but also traversable, the five remaining solutions are all non-asymptotically flat, therefore, the exotic matter from the RDE fluids is spatially distributed in the vicinity of the throat. Furthermore, we analyze the physical characteristics and properties of the RDE traversable wormholes. It is worth noting that, using the astrophysical observations, we obtain the constraints on the parameters of the RDE model, explore the types of exotic RDE fluids in different stages of the universe, limit the number of available models for wormhole research, reduce theoretically the number of the wormholes corresponding to different parameters for the RDE model, and provide a clearer picture for wormhole investigations from the new perspective of observational cosmology.
Holographic Quark Matter and Neutron Stars.
Hoyos, Carlos; Jokela, Niko; Rodríguez Fernández, David; Vuorinen, Aleksi
2016-07-15
We use a top-down holographic model for strongly interacting quark matter to study the properties of neutron stars. When the corresponding equation of state (EOS) is matched with state-of-the-art results for dense nuclear matter, we consistently observe a first-order phase transition at densities between 2 and 7 times the nuclear saturation density. Solving the Tolman-Oppenheimer-Volkov equations with the resulting hybrid EOSs, we find maximal stellar masses in excess of two solar masses, albeit somewhat smaller than those obtained with simple extrapolations of the nuclear matter EOSs. Our calculation predicts that no quark matter exists inside neutron stars.
National Holographic Centre, England: proposal report
NASA Astrophysics Data System (ADS)
Pepper, Andrew T.
1998-02-01
A National Holographic Center has been proposed for construction in England. Its aim is to offer teaching facilities for creative holography to degree level students, the design based holography industry, the local community, school children and members of the public. There are also plans to provide advanced studies and master classes from artists and scientists renowned for their work in the field as well as formal artist-in-residencies. Unlike other teaching and display facilities, this will be a purpose- designed building with labs, gallery space and accommodation for users.
Pulsed Holographic Nondestructive Testing On Aircraft
NASA Astrophysics Data System (ADS)
Fagot, Hubert; Smigielski, Paul; Albe, Felix; Arnaud, Jean-Louis
1983-06-01
An holographic camera composed of two ruby lasers was built at ISL. It provides double exposure holograms with an adjustable time interval ranging from few ns to infinity. Various aircraft structures were first tested at ISL in laboratory conditions: honeycomb panels, wings ... The industrial tests on a military aircraft in maintenance checking were performed in a hangar of the SNIAS at Saint-Nazaire: wings, trap-door of the rear landing gear, air-brake... Electromechanical shocks were used to make the structure vibrate and to allow a fast trigger of the lasers. This avoids disturbance due to ambiant noises and vibrations.
Holographic assembly workstation for optical manipulation
NASA Astrophysics Data System (ADS)
Gibson, Graham; Carberry, David M.; Whyte, Graeme; Leach, Jonathan; Courtial, Johannes; Jackson, Joseph C.; Robert, Daniel; Miles, Mervyn; Padgett, Miles
2008-04-01
We report a holographic assembler workstation for optical trapping and micro-manipulation. The workstation is based on a titanium sapphire laser, making it particularly suited for biomaterials and incorporates a choice of user interfaces for different applications. The system is designed around a commercial inverted microscope and is configured such that it can be easily used by the non-specialist. We demonstrate the bio-capabilities of our system by manipulating a group of yeast cells, a single red blood cell and a single cell of the green algae colony Volvox.
Soft x-ray holographic microscopy
Stickler, Daniel; Froemter, Robert; Stillrich, Holger; Menk, Christian; Oepen, Hans Peter; Tieg, Carsten; Streit-Nierobisch, Simone; Sprung, Michael; Gutt, Christian; Stadler, Lorenz-M.; Leupold, Olaf; Gruebel, Gerhard
2010-01-25
We present a new x-ray microscopy technique based on Fourier transform holography (FTH), where the sample is separate from the optics part of the setup. The sample can be shifted with respect to the holography optics, thus large-scale or randomly distributed objects become accessible. As this extends FTH into a true microscopy technique, we call it x-ray holographic microscopy (XHM). FTH allows nanoscale imaging without the need for nanometer-size beams. Simple Fourier transform yields an unambiguous image reconstruction. We demonstrate XHM by studying the magnetic domain evolution of a Co/Pt multilayer film as function of locally varied iron overlayer thickness.
Holographic collisions in non-conformal theories
NASA Astrophysics Data System (ADS)
Attems, Maximilian; Casalderrey-Solana, Jorge; Mateos, David; Santos-Oliván, Daniel; Sopuerta, Carlos F.; Triana, Miquel; Zilhão, Miguel
2017-01-01
We numerically simulate gravitational shock wave collisions in a holographic model dual to a non-conformal four-dimensional gauge theory. We find two novel effects associated to the non-zero bulk viscosity of the resulting plasma. First, the hydrodynamization time increases. Second, if the bulk viscosity is large enough then the plasma becomes well described by hydrodynamics before the energy density and the average pressure begin to obey the equilibrium equation of state. We discuss implications for the quark-gluon plasma created in heavy ion collision experiments.
Holographic pair and charge density waves
NASA Astrophysics Data System (ADS)
Cremonini, Sera; Li, Li; Ren, Jie
2017-02-01
We examine a holographic model in which a U (1 ) symmetry and translational invariance are broken spontaneously at the same time. Our construction provides an example of a system with pair-density wave order, in which the superconducting order parameter is spatially modulated but has a zero average. In addition, the charge density oscillates at twice the frequency of the scalar condensate. Depending on the choice of parameters, the model also admits a state with coexisting superconducting and charge-density wave orders, in which the scalar condensate has a uniform component.
Uncertainty quantification for holographic interferographic images
NASA Astrophysics Data System (ADS)
Centauri, Laurie Ann
Current comparison methods for experimental and simulated holographic interferometric images are qualitative in nature. Previous comparisons of holographic interferometric images with computational fluid dynamics (CFD) simulations for validation have been performed qualitatively through visual comparison by a data analyst. By validating the experiments and CFD simulations in a quantifiable manner using a consistency analysis, the validation becomes a repeatable process that gives a consistency measure and a range of inputs over which the experiments and CFD simulations give consistent results. The quantification of uncertainty in four holographic interferometric experiments was performed for use in a data collaboration with CFD simulations for the purpose of validation. The model uncertainty from image-processing, the measurement uncertainty from experimental data variation, and the scenario uncertainty from the bias and parameter uncertainty was quantified. The scenario uncertainty was determined through comparison with an analytical solution at the helium inlet (height, x = 0), including the uncertainty in the experimental parameters from historical weather data. The model uncertainty was calculated through a Box-Behnkin sensitivity analysis on three image-processing code parameters. Measurement uncertainty was determined through a statistical analysis to determine the time-average and standard deviation in the interference fringe positions. An experimental design matrix of CFD simulations was performed by Weston Eldredge using a Box-Behnkin design with helium velocity, temperature, and air co-flow velocity as parameters in conjunction to provide simulated measurements for the data collaboration Data set. Over 3,200 holographic interferometric images were processed through the course of this study. When each permutation of these images is taken into account through all the image-processing steps, the total number of images processed is over 13,000. Probability
Holographic frequency modulated continuous wave laser radar
NASA Astrophysics Data System (ADS)
Delaye, P.; Roosen, G.
2007-10-01
We present the operating principle and a first experimental characterization of a holographic rangefinder, that couples a two wave mixing phase demodulation set-up with a frequency modulated laser source. In its first implementation, the system allows millimetre sensitivity on tens of meters measurement range with the ability to work with scattering surfaces. This paper has been presented at “3e colloque interdisciplinaire en instrumentation (C2I 2004)”, École Normale Supérieure de Cachan, 29 30 janvier 2004.
Holographic estimates of the deconfinement temperature
Katanaeva, Alisa; Afonin, Sergey
2016-01-22
The problem of self-consistent estimates of the deconfinement temperature T{sub c} in the framework of the bottom-up holographic approach to QCD is observed. It is shown that the standard soft wall model gives T{sub c} around 260 MeV for planar gluodynamics in a good agreement with the lattice data. The extensions of soft wall model adjusted for descriptions of realistic meson spectra result in a broad range of predictions. This variability is related to a poor experimental information on the radially excited mesons.
High dynamic range holographic data storage media
NASA Astrophysics Data System (ADS)
Askham, Fred; Ayres, Mark R.; Urness, Adam C.
2015-08-01
Holographic data storage (HDS) employs the physics of holography to record digital data in three dimensions in a highly stable photopolymer medium. The photopolymer medium must provide the essential characteristics of low scatter and high dynamic range while maintaining low recording induced physical shrinkage and long archival lifetimes. In this article, we report on media advancements employing Akonia's DREDTM technology which provide a 5x increase in media dynamic range with unchanged media shrinkage. We also discuss the implications of these results for photopolymer media mechanistic models.
Design Rules For Holographic Optical Scanning Elements
NASA Astrophysics Data System (ADS)
Herzig, H. P.; Dandliker, R.
1987-10-01
An analytical method for the design of holographic optical elements (HOE) for focussing laser scanners with minimum aberrations and optimum scan line definition is reported. It can be shown analytically, using second order (paraxial) approximation, that a circular motion of the HOE cannot generate a straight line in space without astigmatism of the focal spot. Accepting a slightly curved scan line, the astigmatism can be compensated. Experimental results for HOE with a wavelength shift between recording and reconstruction are demonstrated. The required aspherical wavefronts for the recording are realized with the help of computer generated holograms (CGH).
Digital Perspective Correction For Cylindrical Holographic Stereograms
NASA Astrophysics Data System (ADS)
Jaffey, Stephen M.; Dutta, Kalyan
1983-04-01
This paper discusses digital perspective correction in the multiplex hologram,also known as Cross hologram or white light cylindrical holographic stereogram. It presents digital analogues of previously reported optical methods, and demonstrates the digital implementation of Benton's method. It introduces a non-linear remapping of the input views to compensate for a non-uniform color viewing position. Simulation results are included on the relative accuracy of different algorithms. Digital correction can be applied to both real and artificial objects such as computed tomography (CT) data.
Holographic experimentation from the student perspective
NASA Astrophysics Data System (ADS)
Niemczura, Johnathan G.
1998-02-01
Conical holograms were produced in a garage, with homemade and surplus equipment, in attempt to capture a 3D image, which includes the top of the objects holographed. They were made from Agfa 8E75 T3 HD NAH film. Developer, bleach and post-treatment were based on Photographers' Formulary JD-3 Holography Processing chemicals. The observation area studied were objects with heights ranging from 24 to 57 mm, with diameters of 25 to 82 mm, and positioned away from the film 13, 17, 20, and 48 mm. Exposure times varied from 6 to 60 seconds. The variables were important to achieving 3D images in the conical holograms.
A simple holographic scenario for gapped quenches
NASA Astrophysics Data System (ADS)
Lopez, Esperanza; del Bosch, Guillermo Milans
2017-02-01
We construct gravitational backgrounds dual to a family of field theories parameterized by a relevant coupling. They combine a non-trivial scalar field profile with a naked singularity. The naked singularity is necessary to preserve Lorentz invariance along the boundary directions. The singularity is however excised by introducing an infrared cutoff in the geometry. The holographic dictionary associated to the infrared boundary is developed. We implement quenches between two different values of the coupling. This requires considering time dependent boundary conditions for the scalar field both at the AdS boundary and the infrared wall.
Drag phenomena from holographic massive gravity
NASA Astrophysics Data System (ADS)
Baggioli, Matteo; Brattan, Daniel K.
2017-01-01
We consider the motion of point particles in a strongly coupled field theory with broken translation invariance. We obtain the energy and momentum loss rates and drag coefficients for a class of such particles by solving for the motion of classical strings in holographic massive gravity. At low temperatures compared to the graviton mass the behaviour of the string is controlled by the appearance of an exotic ground state with non-zero entropy at zero temperature. Additionally, we find an upper bound on the diffusion constant for a collection of these particles which is saturated when the mass of the graviton goes to zero.
NASA Astrophysics Data System (ADS)
Sanders, Robert H.
2014-02-01
1. Introduction; 2. Early history of the dark matter hypothesis; 3. The stability of disk galaxies: the dark halo solutions; 4. Direct evidence: extended rotation curves of spiral galaxies; 5. The maximum disk: light traces mass; 6. Cosmology and the birth of astroparticle physics; 7. Clusters revisited: missing mass found; 8. CDM confronts galaxy rotation curves; 9. The new cosmology: dark matter is not enough; 10. An alternative to dark matter: Modified Newtonian Dynamics; 11. Seeing dark matter: the theory and practice of detection; 12. Reflections: a personal point of view; Appendix; References; Index.
Dark microglia: Why are they dark?
Bisht, Kanchan; Sharma, Kaushik; Lacoste, Baptiste; Tremblay, Marie-Ève
2016-01-01
Using transmission electron microscopy (TEM) we recently characterized a microglial phenotype that is induced by chronic stress, fractalkine receptor deficiency, aging, or Alzheimer disease pathology. These 'dark' microglia appear overly active compared with the normal microglia, reaching for synaptic clefts, and extensively engulfing pre-synaptic axon terminals and post-synaptic dendritic spines. From these findings we hypothesized that dark microglia could be specifically implicated in the pathological remodeling of neuronal circuits, which impairs learning, memory, and other essential cognitive functions. In the present addendum we further discuss about the possible causes of their dark appearance under TEM.
NASA Astrophysics Data System (ADS)
Zhou, Xiang
Using an innovative portable holographic inspection and testing system (PHITS) developed at the Australian Defence Force Academy, fatigue cracks in riveted lap joints can be detected by visually inspecting the abnormal fringe changes recorded on holographic interferograms. In this thesis, for automatic crack detection, some modern digital image processing techniques are investigated and applied to holographic interferogram evaluation. Fringe analysis algorithms are developed for identification of the crack-induced fringe changes. Theoretical analysis of PHITS and riveted lap joints and two typical experiments demonstrate that the fatigue cracks in lightly-clamped joints induce two characteristic fringe changes: local fringe discontinuities at the cracking sites; and the global crescent fringe distribution near to the edge of the rivet hole. Both of the fringe features are used for crack detection in this thesis. As a basis of the fringe feature extraction, an algorithm for local fringe orientation calculation is proposed. For high orientation accuracy and computational efficiency, Gaussian gradient filtering and neighboring direction averaging are used to minimize the effects of image background variations and random noise. The neighboring direction averaging is also used to approximate the fringe directions in centerlines of bright and dark fringes. Experimental results indicate that for high orientation accuracy the scales of the Gaussian filter and neighboring direction averaging should be chosen according to the local fringe spacings. The orientation histogram technique is applied to detect the local fringe discontinuity due to the fatigue cracks. The Fourier descriptor technique is used to characterize the global fringe distribution change from a circular to a crescent distribution with the fatigue crack growth. Experiments and computer simulations are conducted to analyze the detectability and reliability of crack detection using the two techniques. Results
Fan, JiJi; Katz, Andrey; Randall, Lisa; Reece, Matthew
2013-05-24
We point out that current constraints on dark matter imply only that the majority of dark matter is cold and collisionless. A subdominant fraction of dark matter could have much stronger interactions. In particular, it could interact in a manner that dissipates energy, thereby cooling into a rotationally supported disk, much as baryons do. We call this proposed new dark matter component double-disk dark matter (DDDM). We argue that DDDM could constitute a fraction of all matter roughly as large as the fraction in baryons, and that it could be detected through its gravitational effects on the motion of stars in galaxies, for example. Furthermore, if DDDM can annihilate to gamma rays, it would give rise to an indirect detection signal distributed across the sky that differs dramatically from that predicted for ordinary dark matter. DDDM and more general partially interacting dark matter scenarios provide a large unexplored space of testable new physics ideas.
Holographic optical grating and method for optimizing monochromator configuration
Koike, Masato
1999-01-01
This invention comprises a novel apparatus for recording a holographic groove pattern on a diffraction grating blank. The recording apparatus is configured using newly developed groups of analytical equations. The invention further comprises the novel holographic diffraction grating made with the inventive recording apparatus. The invention additionally comprises monochromators and spectrometers equipped with the inventive holographic diffraction grating. Further, the invention comprises a monochromator configured to reduce aberrations using a newly developed group of analytical equations. Additionally, the invention comprises a method to reduce aberrations in monochromators and spectrometers using newly developed groups of analytical equations.
An adaptive holographic implementation of a neural network
NASA Technical Reports Server (NTRS)
Downie, John D.; Hine, Butler P., III; Reid, Max B.
1990-01-01
A holographic implementation for neural networks is proposed and demonstrated as an alternative to the optical matrix-vector multiplier architecture. In comparison, the holographic architecture makes more efficient use of the system space-bandwidth product for certain types of neural networks. The principal network component is a thermoplastic hologram, used to provide both interconnection weights and beam direction. Given the updatable nature of this type of hologram, adaptivity or network learning is possible in the optical system. Two networks with fixed weights are experimentally implemented and verified, and for one of these examples the advantage of the holographic implementation with respect to the matrix-vector processor is demonstrated.
Compact holographic memory using E - O beam steering
NASA Technical Reports Server (NTRS)
Chao, Tien-Hsin; Zhou, Hanying; Reyes, George; Hanan, Jay
2002-01-01
An innovative holographic memory system has been developed at JPL for high-density and high speed data storage in a space environment. This system ulitlizes a newly developed electro-optic (E-O) beam steering technology for beam steering to enable high-speed random access memory read/write without moving parts. Recently, a compact CD-sized holographic memory broadboard has been developed and demonstrated for holographic data storage adn retrieval. Detail technical progress will be presented in this paper.
New model for holographic storage by simultaneous angular multiplexing
NASA Astrophysics Data System (ADS)
Ibarra, J. C.; Urzua, D.; Olivares-Peréz, A.; Ortiz-Gutierrez, M.
2006-05-01
We describe a technique for holographic storage by simultaneous angular multiplexing to obtain a large-scale holographic memory. We recorded 72 objects at the same time in one point on holographic plate PFG-03M from Slavich Co., using a He-Ne laser (λ = 633 nm). Each object is placed on a circular photographic transparency, separate 0.94 degree each one. The technique allows us simultaneous reconstruction of the 72 images without cross-talk. The diffraction efficiency obtained at order one is 6%. Experimental results are shown.
Recent progress in backreacted bottom-up holographic QCD
Järvinen, Matti
2016-01-22
Recent progress in constructing holographic models for QCD is discussed, concentrating on the bottom-up models which implement holographically the renormalization group flow of QCD. The dynamics of gluons can be modeled by using a string-inspired model termed improved holographic QCD, and flavor can be added by introducing space filling branes in this model. The flavor fully backreacts to the glue in the Veneziano limit, giving rise to a class of models which are called V-QCD. The phase diagrams and spectra of V-QCD are in good agreement with results for QCD obtained by other methods.
Pouet, B; Krishnaswamy, S
1996-02-10
A holographic interferometer that uses two-wave mixing in a photorefractive (Bi12SiO20) crystal under an applied ac field is described. The interferometer uses a repetitive sequence of separate record and readout times to obtain quasi real-time holographic interferograms of vibrating objects. It is shown that a good signal-to-noise ratio of the interferometer is obtained by turning off the object illumination and the applied ac field during readout of the hologram. The good signal-to-noise ratio of the resulting holographic interferograms enables phase measurement, which allows for quantitative deformation analysis.
Lensless zoomable holographic projection using scaled Fresnel diffraction.
Shimobaba, Tomoyoshi; Makowski, Michal; Kakue, Takashi; Oikawa, Minoru; Okada, Naohisa; Endo, Yutaka; Hirayama, Ryuji; Ito, Tomoyoshi
2013-10-21
Projectors require a zoom function. This function is generally realized using a zoom lens module composed of many lenses and mechanical parts; however, using a zoom lens module increases the system size and cost, and requires manual operation of the module. Holographic projection is an attractive technique because it inherently requires no lenses, reconstructs images with high contrast and reconstructs color images with one spatial light modulator. In this paper, we demonstrate a lensless zoomable holographic projection. Without using a zoom lens module, this holographic projection realizes the zoom function using a numerical method, called scaled Fresnel diffraction which can calculate diffraction at different sampling rates on a projected image and hologram.
Diffusion in solids with holographic interferometry
NASA Astrophysics Data System (ADS)
Liu, Dingyu
1996-12-01
It is of great importance for the formation of p-n junction in semiconductors by penetrating some impurities through the depth near the surface, so it has long been paid attention to control the concentration distribution of impurities during the diffusion process. In recent years, ionic carburizing, and ion bombardment penetration etc. for the treatment of metal surface have also attracted by material sciences. It requires that the diffusion depth and the diffusion time of the impurities should be under precise control. Different methods, such as the method of radioisotopic detection and the method of chemical analysis have been adopted, however, the reports of different workers are very different, especially in the real time measurement, so, finding new method is never ending. In 1984, H. Fenichel have performed experiments on the solutions of table salt and sugar with the method of holographic interferometry. As for metals which are opaque for the visible light, but they become transparent by making them into a very thin film so that, in principle, the diffusion of atoms within a film is capable of measure by holographic interferometry. Alternatively, the electromagnetic waves within 1 - 70 micrometers wavelengths may be utilized, some materials, such as high purified germanium and silicon are good materials for infrared transmission. Some fluorides of alkaline-earth metals have high transmittance in the range of 1 - 8 micrometers , the concentration of impurities in the semiconductor and metal surface treatment are of 1015 - 1020 atoms per cubic cm, which is capable of detection.
Vibration measurements by pulsed digital holographic endoscopy
NASA Astrophysics Data System (ADS)
Schedin, Staffan; Pedrini, Giancarlo; Perez-Lopez, Carlos; Mendoza Santoyo, Fernando
2005-02-01
Digital holographic interferometry in combination with a flexible fiber endoscope allows high precision measurements of deformations on hidden objects surfaces, inside cavities and objects with small access apertures. A digital holographic endoscopy system is described with a frequency-doubled, twin oscillator Q-switched pulsed Nd:YAG laser as light source. A sequence of digital hologram pairs are recorded with a maximum repetition rate of 260 ms. Each digital hologram is captured at separate video frames of a CCD-camera. The time separation between the laser pulses from each cavity can be set in the range from 50 to 500 μs. The digital holograms are transferred to a PC via a frame grabber and evaluated quantitatively by the Fourier transform method. The resulting phase fringe pattern has the information needed to evaluate quantitatively the amount of the deformation. Experimental results of vibration measurements of hidden mechanical and biological object surfaces are presented. The quality of the results obtained by mechanical object surfaces is usually higher than for biological surfaces. This can be explained easily by the fact that a biological surface is much more complex than a mechanical surface in the sense that some parts of the surface may reflect the light well whereas other parts may absorb the light. Also, biological surfaces are translucent, which means that part of the light may enter inside the sample where it may be absorbed or reflected.
Holographic imaging with single pixel sensor
NASA Astrophysics Data System (ADS)
Leportier, Thibault; Lee, Young Tack; Hwang, Do Kyung; Park, Min-Chul
2016-09-01
Imaging techniques based on CCD sensors presenting very high number of pixels enable to record images with high resolution. However, the huge storage load and high bandwidth required to store and transmit digital holographic information are technical bottlenecks that should be overcome for the future of holographic display. Techniques to capture images with single pixel sensors have been greatly improved recently with the development of compressive sensing algorithm (CS). Since interference patterns may be considered sparse, the number of measurements required to recover the information with CS is lower than the number of pixels of the reconstructed image. In addition, this method does not need any scanning system. One other advantage of single pixel imaging is that the cost of recording system can be dramatically reduced since high-resolution cameras are expensive while compressive sensing exploits only one pixel. In this paper, we present an imaging system based on phase-shifting holography. First, simulations were performed to confirm that hologram could be reconstructed by compressive sensing even if the number of measurements was smaller than the number of pixels. Then, experimental set-up was realized. Several holograms with different phase shifts introduced by quarter and half wave plates in the reference beam were acquired. We demonstrated that our system enables the reconstruction of the object.
X-ray lithography using holographic images
Howells, M.S.; Jacobsen, C.
1997-03-18
Methods for forming X-ray images having 0.25 {micro}m minimum line widths on X-ray sensitive material are presented. A holographic image of a desired circuit pattern is projected onto a wafer or other image-receiving substrate to allow recording of the desired image in photoresist material. In one embodiment, the method uses on-axis transmission and provides a high flux X-ray source having modest monochromaticity and coherence requirements. A layer of light-sensitive photoresist material on a wafer with a selected surface is provided to receive the image(s). The hologram has variable optical thickness and variable associated optical phase angle and amplitude attenuation for transmission of the X-rays. A second embodiment uses off-axis holography. The wafer receives the holographic image by grazing incidence reflection from a hologram printed on a flat metal or other highly reflecting surface or substrate. In this second embodiment, an X-ray beam with a high degree of monochromaticity and spatial coherence is required. 15 figs.
Multiplexed Holographic Data Storage in Bacteriorhodopsin
NASA Technical Reports Server (NTRS)
Mehrl, David J.; Krile, Thomas F.
1999-01-01
Biochrome photosensitive films in particular Bacteriorhodopsin exhibit features which make these materials an attractive recording medium for optical data storage and processing. Bacteriorhodopsin films find numerous applications in a wide range of optical data processing applications; however the short-term memory characteristics of BR limits their applications for holographic data storage. The life-time of the BR can be extended using cryogenic temperatures [1], although this method makes the system overly complicated and unstable. Longer life-times can be provided in one modification of BR - the "blue" membrane BR [2], however currently available films are characterized by both low diffraction efficiency and difficulties in providing photoreversible recording. In addition, as a dynamic recording material, the BR requires different wavelengths for recording and reconstructing of optical data in order to prevent the information erasure during its readout. This fact also put constraints on a BR-based Optical Memory, due to information loss in holographic memory systems employing the two-lambda technique for reading-writing thick multiplexed holograms.
Holographic bound in covariant loop quantum gravity
NASA Astrophysics Data System (ADS)
Tamaki, Takashi
2016-07-01
We investigate puncture statistics based on the covariant area spectrum in loop quantum gravity. First, we consider Maxwell-Boltzmann statistics with a Gibbs factor for punctures. We establish formulas which relate physical quantities such as horizon area to the parameter characterizing holographic degrees of freedom. We also perform numerical calculations and obtain consistency with these formulas. These results tell us that the holographic bound is satisfied in the large area limit and the correction term of the entropy-area law can be proportional to the logarithm of the horizon area. Second, we also consider Bose-Einstein statistics and show that the above formulas are also useful in this case. By applying the formulas, we can understand intrinsic features of Bose-Einstein condensate which corresponds to the case when the horizon area almost consists of punctures in the ground state. When this phenomena occurs, the area is approximately constant against the parameter characterizing the temperature. When this phenomena is broken, the area shows rapid increase which suggests the phase transition from quantum to classical area.
Miniaturized low-cost digital holographic interferometer
NASA Astrophysics Data System (ADS)
Michalkiewicz, Aneta; Kujawinska, Małgorzata; Marc, Paweł; Jaroszewicz, Leszek R.
2006-04-01
Digital holography (DH) and digital holographic interferometry (DHI) are very useful, robust, full-field visualization and measurement techniques applied for small objects, especially in the field of bioengineering and microelements system testing. Nowadays CCD/CMOS detectors and microlasers allow to build miniaturized and compact digital holographic head. Various approaches to develop DH/DHI systems including a variety of optical and mechanical solutions have been made. The main recent requirements for holocamera design include compactness, insensitivity to vibrations environmental changes and with good quality of output data. Other requirement is the ability to build a low-cost and robust system for sensing applications. In our paper, we propose a design of miniaturized holo-camera head with fibre optics light delivery system and remote data read-out. The opto-mechanical architecture allows out-of-plane and shape measurements of diffuse and reflective surfaces. The possible data capture schemes and software for enhanced quality numerical reconstruction of complex objects are discussed and the optimized methodology is determined. Also real-time optoelectronic hologram reconstruction is demonstrated on the base of remote data delivery to liquid crystal on silicon spatial light modulator. The performance of the system is tested on the resolution amplitude test and master sphere, while engineering objects in the experiments are static and dynamic microelements.
Dark Forces and Light Dark Matter
Hooper, Dan; Weiner, Neal; Xue, Wei
2012-09-01
We consider a simple class of models in which the dark matter, X, is coupled to a new gauge boson, phi, with a relatively low mass (m_phi \\sim 100 MeV-3 GeV). Neither the dark matter nor the new gauge boson have tree-level couplings to the Standard Model. The dark matter in this model annihilates to phi pairs, and for a coupling of g_X \\sim 0.06 (m_X/10 GeV)^1/2 yields a thermal relic abundance consistent with the cosmological density of dark matter. The phi's produced in such annihilations decay through a small degree of kinetic mixing with the photon to combinations of Standard Model leptons and mesons. For dark matter with a mass of \\sim10 GeV, the shape of the resulting gamma-ray spectrum provides a good fit to that observed from the Galactic Center, and can also provide the very hard electron spectrum required to account for the observed synchrotron emission from the Milky Way's radio filaments. For kinetic mixing near the level naively expected from loop-suppressed operators (epsilon \\sim 10^{-4}), the dark matter is predicted to scatter elastically with protons with a cross section consistent with that required to accommodate the signals reported by DAMA/LIBRA, CoGeNT and CRESST-II.
NASA Technical Reports Server (NTRS)
1974-01-01
Developments in the area of organic cis-trans isomerization systems for holographic memory applications are reported. The chemical research effort consisted of photochemical studies leading to the selection of a stilbene derivative and a polymer matrix system which have greatly improved refractive index differences between the cis and trans isomers as well as demonstrated efficiency of the photoisomerization process. In work on lithium niobate effects of sample stoichiometry and of read and write beam polarizations on recording efficiency were investigated. LiNbO3 was used for a study of angular sensitivity and of capability for simultaneous recording of extended objects without interference. The current status of LiNbO3 as a holographic recording material is summarized.
NASA Astrophysics Data System (ADS)
Sarfatti, Jack; Levit, Creon
2009-06-01
We present a model for the origin of gravity, dark energy and dark matter: Dark energy and dark matter are residual pre-inflation false vacuum random zero point energy (w = - 1) of large-scale negative, and short-scale positive pressure, respectively, corresponding to the "zero point" (incoherent) component of a superfluid (supersolid) ground state. Gravity, in contrast, arises from the 2nd order topological defects in the post-inflation virtual "condensate" (coherent) component. We predict, as a consequence, that the LHC will never detect exotic real on-mass-shell particles that can explain dark matter ΩMDM approx 0.23. We also point out that the future holographic dark energy de Sitter horizon is a total absorber (in the sense of retro-causal Wheeler-Feynman action-at-a-distance electrodynamics) because it is an infinite redshift surface for static detectors. Therefore, the advanced Hawking-Unruh thermal radiation from the future de Sitter horizon is a candidate for the negative pressure dark vacuum energy.
Ibarra, Alejandro
2015-07-15
Neutrinos could be key particles to unravel the nature of the dark matter of the Universe. On the one hand, sterile neutrinos in minimal extensions of the Standard Model are excellent dark matter candidates, producing potentially observable signals in the form of a line in the X-ray sky. On the other hand, the annihilation or the decay of dark matter particles produces, in many plausible dark matter scenarios, a neutrino flux that could be detected at neutrino telescopes, thus providing non-gravitational evidence for dark matter. More conservatively, the non-observation of a significant excess in the neutrino fluxes with respect to the expected astrophysical backgrounds can be used to constrain dark matter properties, such as the self-annihilation cross section, the scattering cross section with nucleons and the lifetime.
Holographic analogy of the spatial radial carrier analysis of interferograms
NASA Astrophysics Data System (ADS)
Garcia-Marquez, Jorge L.; Malacara-Hernandez, Daniel
1996-07-01
A holographic analogy ofthe analysis of thterferograms with a spatial radial carrier introduced by means of defocusing and its practical applications is describei Special emphasis is made ofthe conditions imposed on the Fourier spectra ofthe interferogram.
A holographic proof of Rényi entropic inequalities
NASA Astrophysics Data System (ADS)
Nakaguchi, Yuki; Nishioka, Tatsuma
2016-12-01
We prove Rényi entropic inequalities in a holographic setup based on the recent proposal for the holographic formula of Rényi entropies when the bulk is stable against any perturbation. Regarding the Rényi parameter as an inverse temperature, we reformulate the entropies in analogy with statistical mechanics, which provides us a concise interpretation of the inequalities as the positivities of entropy, energy and heat capacity. This analogy also makes clear a thermodynamic structure in deriving the holographic formula. As a by-product of the proof we obtain a holographic formula to calculate the quantum fluctuation of the modular Hamiltonian. A few examples of the capacity of entanglement are examined in detail.
Characterization of quantum phase transition using holographic entanglement entropy
NASA Astrophysics Data System (ADS)
Ling, Yi; Liu, Peng; Wu, Jian-Pin
2016-06-01
The entanglement exhibits extremal or singular behavior near quantum critical points (QCPs) in many condensed matter models. These intriguing phenomena, however, still call for a widely accepted understanding. In this paper we study this issue in holographic framework. We investigate the connection between the holographic entanglement entropy (HEE) and the quantum phase transition (QPT) in a lattice-deformed Einstein-Maxwell-Dilaton theory. Novel backgrounds exhibiting metal-insulator transitions (MIT) have been constructed in which both metallic phase and insulating phase have vanishing entropy density in zero temperature limit. We find that the first order derivative of HEE with respect to lattice parameters exhibits extremal behavior near QCPs. We propose that it would be a universal feature that HEE or its derivatives with respect to system parameters can characterize QPT in a generic holographic system. Our work opens a window for understanding the relation between entanglement and the QPT from a holographic perspective.
Holographic face models as planning tool in maxillofacial surgery.
Mischkowski, R A; Bongartz, J; Giel, D; Frey, S; Thelen, A; Hering, P
2004-10-01
The holographic facial profile scan is a new technique for creation of high-resolution, three-dimensional, realistic facial computer models which can be used for surgical planning and documentation in maxillofacial surgery. First, a holographic image of the patient is recorded using a pulsed laser system. In a second step, called holographic tomography, the real image of the patient's hologram is reconstructed by means of a continuous-wave laser. By moving a screen through the real three-dimensional image, it is sliced into a series of two-dimensional projections which are captured with a digital camera. The slices containing the specific two-dimensional information are superimposed to a three-dimensional surface model using special software. The extremely short exposure time of 35 nanoseconds for taking a holographic image is separated from the time-consuming rendering process of the surface model; thus, the obtained models are not affected by the movements of the patient.
Study on spectrometer based upon volume holographic transmission grating
NASA Astrophysics Data System (ADS)
Huang, Zhen; Liu, Guodong; Ren, Zhong; Zeng, Lvming
2010-10-01
In this present paper, a spectrometer based upon axial transmissive optical structure with the volume-phase holographic (VPH) transmission grating technology is introduced. We give a physical insight for the structure and mechanism of photorefractive volume holographic gratings and theoretically analyze some important performance parameters of the spectrometer device using the coupled wave theory, which should be considered in the process of the following design for the device with volume phase holographic transmission gratings. The experimental results show, owing to its axial transmissive optical geometry and the perfect performance of the VPH transmission grating, the spectrometer based on the volume-phase holographic transmission grating has satisfactory high resolution and wavelength accuracy. It has great promise to be widely used in the future.
Automated Digital Analysis Of Holographic Interferograms Of Pure Translations
NASA Astrophysics Data System (ADS)
Choudry, A.; Frankena, H. J.; van Beek, J. W.
1983-10-01
Holographic interferometry is a versatile technique for non-tactile measurement of changes in a wide variety of physical variables such as temperature, strain, position etc. It has a great potential for becoming an important metrologic technique in industrial applications. For holographic interferometry to become more attractive for industrial practice the problem of quantitative analysis of the patterns and thereby eliciting reliable values of the relevant parameters has to be addressed. In an attempt to calibrate the technique of holographic interferometry and ascertain the reliability of the subsequent digital analysis, we have chosen precisely known translations as a basis. Holographic interferograms taken from these are analysed manually and by digital techniques specially developed for such patterns. The results are promising enough to indicate the feasibility of automated digital analysis for determining translations within an acceptable accuracy. Some details of the evaluation techniques, along with a brief discussion of the preliminary results are presented.
3D Holographic Technology and Its Educational Potential
ERIC Educational Resources Information Center
Lee, Hyangsook
2013-01-01
This article discusses a number of significant developments in 3D holographic technology, its potential to revolutionize aspects of teaching and learning, and challenges of implementing the technology in educational settings.
Quantitative measurement of holographic image quality using Adobe Photoshop
NASA Astrophysics Data System (ADS)
Wesly, E.
2013-02-01
Measurement of the characteristics of image holograms in regards to diffraction efficiency and signal to noise ratio are demonstrated, using readily available digital cameras and image editing software. Illustrations and case studies, using currently available holographic recording materials, are presented.
Holographic Interferometric Measurement of Motions in Mature Plants 1
Fox, Martin D.; Puffer, Leroy G.
1977-01-01
Holographic interferometry has been used to plot graphs of the phototropic and geotropic bending undergone by a mature Stapelia variegata Linn over a 5-minute period. The holographic interferometric technique is shown to have the advantage of measuring displacements at least as small as 0.16 micrometers which permits observation of extremely slow plant motions over time periods of a few minutes. In addition, the holographic technique provides a permanent record of displacement information over the entire plant in a single hologram. The short 5-minute period required to produce a holographic interferogram has permitted the monitoring of slow plant motions by recording a series of consecutive holograms at 5-minute intervals over a 75-minute period. The results have been plotted on a graph thereby capturing for the first time such small displacement, velocity, and acceleration of a mature plant as a function of time. Images PMID:16660036
NASA Technical Reports Server (NTRS)
Silk, Joseph; Stebbins, Albert
1993-01-01
A study is conducted of cold dark matter (CDM) models in which clumpiness will inhere, using cosmic strings and textures suited to galaxy formation. CDM clumps of 10 million solar mass/cu pc density are generated at about z(eq) redshift, with a sizable fraction surviving. Observable implications encompass dark matter cores in globular clusters and in galactic nuclei. Results from terrestrial dark matter detection experiments may be affected by clumpiness in the Galactic halo.
NASA Astrophysics Data System (ADS)
Schumann, Marc
2014-10-01
This article reviews the status of the exciting and fastly evolving field of dark matter research as of summer 2013, when it was discussed at the International Cosmic Ray Conference (ICRC) 2013 in Rio de Janeiro. It focuses on the three main avenues to detect weakly interacting massive particle (WIMP) dark matter: direct detection, indirect detection, and collider searches. The article is based on the dark matter rapporteur talk summarizing the presentations given at the conference, filling some gaps for completeness.
Cruz, Norman; Palma, Guillermo; Zambrano, David; Avelino, Arturo E-mail: guillermo.palma@usach.cl E-mail: avelino@fisica.ugto.mx
2013-05-01
We explore a cosmological model composed by a dark matter fluid interacting with a dark energy fluid. The interaction term has the non-linear λρ{sub m}{sup α}ρ{sub e}{sup β} form, where ρ{sub m} and ρ{sub e} are the energy densities of the dark matter and dark energy, respectively. The parameters α and β are in principle not constrained to take any particular values, and were estimated from observations. We perform an analytical study of the evolution equations, finding the fixed points and their stability properties in order to characterize suitable physical regions in the phase space of the dark matter and dark energy densities. The constants (λ,α,β) as well as w{sub m} and w{sub e} of the EoS of dark matter and dark energy respectively, were estimated using the cosmological observations of the type Ia supernovae and the Hubble expansion rate H(z) data sets. We find that the best estimated values for the free parameters of the model correspond to a warm dark matter interacting with a phantom dark energy component, with a well goodness-of-fit to data. However, using the Bayesian Information Criterion (BIC) we find that this model is overcame by a warm dark matter – phantom dark energy model without interaction, as well as by the ΛCDM model. We find also a large dispersion on the best estimated values of the (λ,α,β) parameters, so even if we are not able to set strong constraints on their values, given the goodness-of-fit to data of the model, we find that a large variety of theirs values are well compatible with the observational data used.
Holographic molecularly imprinted polymers for label-free chemical sensing.
Fuchs, Yannick; Soppera, Olivier; Mayes, Andrew G; Haupt, Karsten
2013-01-25
Holographic molecularly imprinted polymer films for the use in chemical sensors are obtained in one step through photopolymerization with interfering laser beams. This results in hierarchical structuring at four length scales: micrometer-scale patterning of millimeter- to centimeter- size polymer objects with holographic optical properties, exhibiting nanometer-scale porosity and specific molecular recognition properties at the molecular scale through self-assembly. Specific binding of the target analyte testosterone is measured by diffraction analysis.
High speed optical object recognition processor with massive holographic memory
NASA Technical Reports Server (NTRS)
Chao, T.; Zhou, H.; Reyes, G.
2002-01-01
Real-time object recognition using a compact grayscale optical correlator will be introduced. A holographic memory module for storing a large bank of optimum correlation filters, to accommodate the large data throughput rate needed for many real-world applications, has also been developed. System architecture of the optical processor and the holographic memory will be presented. Application examples of this object recognition technology will also be demonstrated.
Holographic data storage crystals for LDEF (A0044)
NASA Technical Reports Server (NTRS)
Callen, W. R.; Gaylord, T. K.
1984-01-01
Electro-optic holographic recording systems were developed. The spaceworthiness of electro-optic crystals for use in ultrahigh capacity space data storage and retrieval systems are examined. The crystals for this experiment are included with the various electro-optical components of LDEF experiment. The effects of long-duration exposure on active optical system components is investigated. The concept of data storage in an optical-phase holographic memory is illustrated.
Holographic superconductor developed in BTZ black hole background with backreactions
NASA Astrophysics Data System (ADS)
Liu, Yunqi; Pan, Qiyuan; Wang, Bin
2011-08-01
We develop a holographic superconductor in BTZ black hole background with backreactions. We investigate the influence of the backreaction on the condensation of the scalar hair and the dynamics of perturbation in the background spacetime. When the Breitenlohner-Freedman bound is approached, we argue that only one of two possible operators can reflect the real property of the condensation in the holographic superconductor. This argument is supported by the investigation in dynamics.
Real-time laser holographic Interferometry for aerodynamics
NASA Technical Reports Server (NTRS)
Lee, George
1987-01-01
Recent developments in thermoplastic recording holograms and advancements in automated image digitalization and analysis make real-time laser holographic interferometry feasible for two-dimensional flows such as airfoil flows. Typical airfoil measurements would include airfoil presssure distributions, wake and boundary layer profiles, and flow field density contours. This paper addresses some of the problems and requirements of a real-time laser holographic interferometer.
Real-time laser holographic interferometry for aerodynamics
NASA Technical Reports Server (NTRS)
Lee, George
1987-01-01
Recent developments in thermoplastic recording holograms and advancements in automated image digitalization and analysis make real-time laser holographic interferometry feasible for two-dimensional flows such as airfoil flows. Typical airfoil measurements would include airfoil pressure distributions, wake and boundary layer profiles, and flow field density contours. This paper addresses some of the problems and requirements of a real-time laser holographic interferometer.
Experimental holographic read-write memory using 3-d storage.
d'Auria, L; Huignard, J P; Slezak, C; Spitz, E
1974-04-01
A mockup of an experimental 3-D holographic read-write memory is described. The storage technique uses superimposed holographic pages in a thick photosensitive medium. Access to any page is obtained by reference beam rotation about each selected page. The experimental arrangement consists of a partially filled memory plane. The thick erasable storage medium used is iron-doped lithium niobate. The paper also includes experimental results on the deflector device, page composer, and readout systems.
Schramm, D.N.
1992-03-01
The cosmological dark matter problem is reviewed. The Big Bang Nucleosynthesis constraints on the baryon density are compared with the densities implied by visible matter, dark halos, dynamics of clusters, gravitational lenses, large-scale velocity flows, and the {Omega} = 1 flatness/inflation argument. It is shown that (1) the majority of baryons are dark; and (2) non-baryonic dark matter is probably required on large scales. It is also noted that halo dark matter could be either baryonic or non-baryonic. Descrimination between cold'' and hot'' non-baryonic candidates is shown to depend on the assumed seeds'' that stimulate structure formation. Gaussian density fluctuations, such as those induced by quantum fluctuations, favor cold dark matter, whereas topological defects such as strings, textures or domain walls may work equally or better with hot dark matter. A possible connection between cold dark matter, globular cluster ages and the Hubble constant is mentioned. Recent large-scale structure measurements, coupled with microwave anisotropy limits, are shown to raise some questions for the previously favored density fluctuation picture. Accelerator and underground limits on dark matter candidates are also reviewed.
Schramm, D.N.
1992-03-01
The cosmological dark matter problem is reviewed. The Big Bang Nucleosynthesis constraints on the baryon density are compared with the densities implied by visible matter, dark halos, dynamics of clusters, gravitational lenses, large-scale velocity flows, and the {Omega} = 1 flatness/inflation argument. It is shown that (1) the majority of baryons are dark; and (2) non-baryonic dark matter is probably required on large scales. It is also noted that halo dark matter could be either baryonic or non-baryonic. Descrimination between ``cold`` and ``hot`` non-baryonic candidates is shown to depend on the assumed ``seeds`` that stimulate structure formation. Gaussian density fluctuations, such as those induced by quantum fluctuations, favor cold dark matter, whereas topological defects such as strings, textures or domain walls may work equally or better with hot dark matter. A possible connection between cold dark matter, globular cluster ages and the Hubble constant is mentioned. Recent large-scale structure measurements, coupled with microwave anisotropy limits, are shown to raise some questions for the previously favored density fluctuation picture. Accelerator and underground limits on dark matter candidates are also reviewed.
NASA Astrophysics Data System (ADS)
Landim, Ricardo G.; Abdalla, Elcio
2017-01-01
We build a model of metastable dark energy, in which the observed vacuum energy is the value of the scalar potential at the false vacuum. The scalar potential is given by a sum of even self-interactions up to order six. The deviation from the Minkowski vacuum is due to a term suppressed by the Planck scale. The decay time of the metastable vacuum can easily accommodate a mean life time compatible with the age of the universe. The metastable dark energy is also embedded into a model with SU(2)R symmetry. The dark energy doublet and the dark matter doublet naturally interact with each other. A three-body decay of the dark energy particle into (cold and warm) dark matter can be as long as large fraction of the age of the universe, if the mediator is massive enough, the lower bound being at intermediate energy level some orders below the grand unification scale. Such a decay shows a different form of interaction between dark matter and dark energy, and the model opens a new window to investigate the dark sector from the point-of-view of particle physics.
Dark energy and extended dark matter halos
NASA Astrophysics Data System (ADS)
Chernin, A. D.; Teerikorpi, P.; Valtonen, M. J.; Dolgachev, V. P.; Domozhilova, L. M.; Byrd, G. G.
2012-03-01
The cosmological mean matter (dark and baryonic) density measured in the units of the critical density is Ωm = 0.27. Independently, the local mean density is estimated to be Ωloc = 0.08-0.23 from recent data on galaxy groups at redshifts up to z = 0.01-0.03 (as published by Crook et al. 2007, ApJ, 655, 790 and Makarov & Karachentsev 2011, MNRAS, 412, 2498). If the lower values of Ωloc are reliable, as Makarov & Karachentsev and some other observers prefer, does this mean that the Local Universe of 100-300 Mpc across is an underdensity in the cosmic matter distribution? Or could it nevertheless be representative of the mean cosmic density or even be an overdensity due to the Local Supercluster therein. We focus on dark matter halos of groups of galaxies and check how much dark mass the invisible outer layers of the halos are able to host. The outer layers are usually devoid of bright galaxies and cannot be seen at large distances. The key factor which bounds the size of an isolated halo is the local antigravity produced by the omnipresent background of dark energy. A gravitationally bound halo does not extend beyond the zero-gravity surface where the gravity of matter and the antigravity of dark energy balance, thus defining a natural upper size of a system. We use our theory of local dynamical effects of dark energy to estimate the maximal sizes and masses of the extended dark halos. Using data from three recent catalogs of galaxy groups, we show that the calculated mass bounds conform with the assumption that a significant amount of dark matter is located in the invisible outer parts of the extended halos, sufficient to fill the gap between the observed and expected local matter density. Nearby groups of galaxies and the Virgo cluster have dark halos which seem to extend up to their zero-gravity surfaces. If the extended halo is a common feature of gravitationally bound systems on scales of galaxy groups and clusters, the Local Universe could be typical or even
Asymmetric Dark Matter and Dark Radiation
Blennow, Mattias; Martinez, Enrique Fernandez; Mena, Olga; Redondo, Javier; Serra, Paolo E-mail: enfmarti@cern.ch E-mail: redondo@mppmu.mpg.de
2012-07-01
Asymmetric Dark Matter (ADM) models invoke a particle-antiparticle asymmetry, similar to the one observed in the Baryon sector, to account for the Dark Matter (DM) abundance. Both asymmetries are usually generated by the same mechanism and generally related, thus predicting DM masses around 5 GeV in order to obtain the correct density. The main challenge for successful models is to ensure efficient annihilation of the thermally produced symmetric component of such a light DM candidate without violating constraints from collider or direct searches. A common way to overcome this involves a light mediator, into which DM can efficiently annihilate and which subsequently decays into Standard Model particles. Here we explore the scenario where the light mediator decays instead into lighter degrees of freedom in the dark sector that act as radiation in the early Universe. While this assumption makes indirect DM searches challenging, it leads to signals of extra radiation at BBN and CMB. Under certain conditions, precise measurements of the number of relativistic species, such as those expected from the Planck satellite, can provide information on the structure of the dark sector. We also discuss the constraints of the interactions between DM and Dark Radiation from their imprint in the matter power spectrum.
Holographic renormalization group and cosmology in theories with quasilocalized gravity
NASA Astrophysics Data System (ADS)
Csáki, Csaba; Erlich, Joshua; Hollowood, Timothy J.; Terning, John
2001-03-01
We study the long distance behavior of brane theories with quasilocalized gravity. The five-dimensional (5D) effective theory at large scales follows from a holographic renormalization group flow. As intuitively expected, the graviton is effectively four dimensional at intermediate scales and becomes five dimensional at large scales. However, in the holographic effective theory the essentially 4D radion dominates at long distances and gives rise to scalar antigravity. The holographic description shows that at large distances the Gregory-Rubakov-Sibiryakov (GRS) model is equivalent to the model recently proposed by Dvali, Gabadadze, and Porrati (DGP), where a tensionless brane is embedded into 5D Minkowski space, with an additional induced 4D Einstein-Hilbert term on the brane. In the holographic description the radion of the GRS model is automatically localized on the tensionless brane, and provides the ghostlike field necessary to cancel the extra graviton polarization of the DGP model. Thus, there is a holographic duality between these theories. This analysis provides physical insight into how the GRS model works at intermediate scales; in particular it sheds light on the size of the width of the graviton resonance, and also demonstrates how the holographic renormalization group can be used as a practical tool for calculations.
Printable Nanophotonic Devices via Holographic Laser Ablation.
Zhao, Qiancheng; Yetisen, Ali K; Sabouri, Aydin; Yun, Seok Hyun; Butt, Haider
2015-09-22
Holography plays a significant role in applications such as data storage, light trapping, security, and biosensors. However, conventional fabrication methods remain time-consuming, costly, and complex, limiting the fabrication of holograms and their extensive use. Here, we demonstrate a single-pulse laser ablation technique to write parallel surface gratings and Fresnel zone plates. We utilized a 6 ns high-energy green laser pulse to form interference patterns to record a surface grating with 820 nm periodicity and asymmetric zone plate holograms on 4.5 nm gold-coated substrates. The holographic recording process was completed within seconds. The optical characteristics of the interference patterns have been computationally modeled, and well-ordered polychromatic diffraction was observed from the fabricated holograms. The zone plate showed a significant diffraction angle of 32° from the normal incident for the focal point. The nanosecond laser interference ablation for rapid hologram fabrication holds great potential in a vast range of optical devices.
Shell deformation studies using holographic interferometry
NASA Technical Reports Server (NTRS)
Parmerter, R. R.
1974-01-01
The buckling of shallow spherical shells under pressure has been the subject of many theoretical and experimental papers. Experimental data above the theoretical buckling load of Huang have given rise to speculation that shallow shell theory may not adequately predict the stability of nonsymmetric modes in higher-rise shells which are normally classified as shallow by the Reissner criterion. This article considers holographic interferometry as a noncontact, high-resolution method of measuring prebuckling deformations. Prebuckling deformations of a lambda = 9, h/b = 0.038 shell are Fourier-analyzed. Buckling is found to occur in an N = 5 mode as predicted by Huang's theory. The N = 4 mode was unusually stable, suggesting that even at this low value of h/b, stabilizing effects may be at work.
Holographic integral equations and walking technicolor
Alvares, Raul; Evans, Nick; Gebauer, Astrid; Weatherill, George James
2010-01-15
We study chiral symmetry breaking in the holographic D3-D7 system in a simple model with an arbitrary running coupling. We derive equations for the D7 embedding and show there is a light pion. In particular we present simple integral equations, involving just the running coupling and the quark self-energy, for the quark condensate and the pion decay constant. We compare these to the Pagels-Stokar or constituent quark model equivalent. We discuss the implications for walking technicolor theories. We also perform a similar analysis in the four-dimensional field theory whose dual is the nonsupersymmetric D3-D5 system and propose that it represents a walking theory in which the quark condensate has dimension 2+{radical}(3)
Very high speed cw digital holographic interferometry
NASA Astrophysics Data System (ADS)
Pérez-López, Carlos; de La Torre-Ibarra, Manuel H.; Mendoza Santoyo, Fernando
2006-10-01
It is reported for the first time the use of a very high speed camera in digital holographic interferometry with an out of plane sensitivity setup. The image plane holograms of a spherical latex balloon illuminated by a cw laser were acquired at a rate of 4000 frames per second, representing a time spacing between holograms of 250 microseconds, for 512 × 512 pixels at 8 bits resolution. Two types of tests were accomplished for a proof of principle of the technique, one with no constrains on the object which meant random movements due to non controlled environmental air currents, and the other with specific controlled conditions on the object. Results presented correspond to a random sample of sequential digital holograms, chosen from a 1 second exposure, individually Fourier processed in order to perform the usual comparison by subtraction between consecutive pairs thus obtaining the phase map of the object out of plane displacement, shown as a movie.
Holographic considerations on a Machian Universe
Abreu, Everton M.C.; Ananias Neto, Jorge
2014-12-15
MOND theory explains the rotation curves of the galaxies. Verlinde’s ideas establish an entropic origin for gravitational forces and Tsallis principle generalizes the theory of Boltzmann–Gibbs. In this work we have promoted a connection between these recent approaches, that at first sight seemed to have few or no points in common, using the Mach’s principle as the background. In this way we have used Tsallis formalism to calculate the main parameters of the Machian Universe including the Hubble parameter and the age of the Universe. After that, we have also obtained a new value for the Tsallis parameter via Mach’s principle. Using Verlinde’s entropic gravity we have obtained new forms for MOND’s well established ingredients. Finally, based on the relations between particles and bits obtained here, we have discussed the idea of bits entanglement in the holographic screen.
Real time moving scene holographic camera system
NASA Technical Reports Server (NTRS)
Kurtz, R. L. (Inventor)
1973-01-01
A holographic motion picture camera system producing resolution of front surface detail is described. The system utilizes a beam of coherent light and means for dividing the beam into a reference beam for direct transmission to a conventional movie camera and two reflection signal beams for transmission to the movie camera by reflection from the front side of a moving scene. The system is arranged so that critical parts of the system are positioned on the foci of a pair of interrelated, mathematically derived ellipses. The camera has the theoretical capability of producing motion picture holograms of projectiles moving at speeds as high as 900,000 cm/sec (about 21,450 mph).
Vortex flow for a holographic superconductor
Maeda, Kengo; Okamura, Takashi
2011-03-15
We investigate energy dissipation associated with the motion of the scalar condensate in a holographic superconductor model constructed from the charged scalar field coupled to the Maxwell field. Upon application of constant magnetic and electric fields, we analytically construct the vortex-flow solution and find the vortex-flow resistance near the second-order phase transition where the scalar condensate begins. The characteristic feature of the nonequilibrium state agrees with the one predicted by the time-dependent Ginzburg-Landau (TDGL) theory. We evaluate the kinetic coefficient in the TDGL equation along the line of the second-order phase transition. At zero magnetic field, the other coefficients in the TDGL equation are also evaluated just below the critical temperature.
Holographic phase transitions at finite chemical potential
NASA Astrophysics Data System (ADS)
Mateos, David; Matsuura, Shunji; Myers, Robert C.; Thomson, Rowan M.
2007-11-01
Recently, holographic techniques have been used to study the thermal properties of Script N = 2 super-Yang-Mills theory, with gauge group SU(Nc) and coupled to Nf << Nc flavours of fundamental matter, at large Nc and large 't Hooft coupling. Here we consider the phase diagram as a function of temperature and baryon chemical potential μb. For fixed μb < NcMq there is a line of first order thermal phase transitions separating a region with vanishing baryon density and one with nonzero density. For fixed μb>Nc Mq there is no phase transition as a function of the temperature and the baryon density is always nonzero. We also compare the present results for the grand canonical ensemble with those for canonical ensemble in which the baryon density is held fixed [1].
Long Holographic Lifetimes in Bacteriorhodopsin Films
NASA Technical Reports Server (NTRS)
Downie, John D.; Smithey, Daniel T.; Timucin, Dogan A.; Crew, Marshall
1998-01-01
The D85N genetic variant of bacteriorhodopsin displays a nearly permanent lifetime of the photochromic P490 state. We present pump-probe measurements that demonstrate this behavior. However, experimental diffraction efficiency measurements made from holograms recorded in a hydrated D85N film show markedly different decay behavior, suggesting a molecular diffusion process occurring in the film. Holograms recorded with different grating frequencies display correspondingly different decay times which support this hypothesis. A thin D85N film was then fabricated which was chemically crosslinked, resulting in the elimination of diffusion of BR molecules within the polymer matrix. This film exhibits a grating lifetime on the order of weeks or more, thus allowing the long term holographic storage of information in a BR film.
Single port access holographic particle image velocimetry
Woodruff, S.D.; Richards, G.A.; Cha, D.J.
1995-07-01
An optical system, which requires only a single optical window mounted on a test volume, is proposed for holographic particle image velocimetry (HPIV). The optical system is a derivative of the double-exposure, double-reference-beam, off-axis HPIV system, but the innovative idea behind the system is to use back scattered light from the particles as the object wave. A 45{degree} beam splitter inserted in front of the window serves to admit the illuminating beam and extract the back scattered light. This concept can be of great engineering interest because optical access is often limited to one window in practical devices. The preliminary results of the technique appear quite promising, with current studies aimed at defining the optical resolution capabilities.
Multiplexed spectroscopy with holographic optical tweezers
NASA Astrophysics Data System (ADS)
Cibula, Matthew A.; McIntyre, David H.
2014-09-01
We have developed a multiplexed holographic optical tweezers system with an imaging spectrometer to manipulate multiple optically trapped nanosensors and detect multiple fluorescence spectra. The system uses a spatial light modulator (SLM) to control the positions of infrared optical traps in the sample so that multiple nanosensors can be positioned into regions of interest. Spectra of multiple nanosensors are detected simultaneously with the application of an imaging spectrometer. Nanosensors are capable of detecting changes in their environment such as pH, ion concentration, temperature, and voltage by monitoring changes in the nanosensors' emitted fluorescence spectra. We use streptavidin labeled quantum dots bound to the surface of biotin labeled polystyrene microspheres to measure temperature changes by observing a corresponding shift in the wavelength of the spectral peak. The fluorescence is excited at 532 nm with a wide field source.
Holographic entanglement entropy of surface defects
NASA Astrophysics Data System (ADS)
Gentle, Simon A.; Gutperle, Michael; Marasinou, Chrysostomos
2016-04-01
We calculate the holographic entanglement entropy in type IIB supergravity solutions that are dual to half-BPS disorder-type surface defects in N=4 supersymmetric Yang-Mills theory. The entanglement entropy is calculated for a ball-shaped region bisected by a surface defect. Using the bubbling supergravity solutions we also compute the expectation value of the defect operator. Combining our result with the previously-calculated one-point function of the stress tensor in the presence of the defect, we adapt the calculation of Lewkowycz and Maldacena [1] to obtain a second expression for the entanglement entropy. Our two expressions agree up to an additional term, whose possible origin and significance is discussed.
Astronomical telescope with holographic primary objective
NASA Astrophysics Data System (ADS)
Ditto, Thomas D.; Friedman, Jeffrey F.; Content, David A.
2011-09-01
A dual dispersion telescope with a plane grating primary objective was previously disclosed that can overcome intrinsic chromatic aberration of dispersive optics while allowing for unprecedented features such as million object spectroscopy, extraordinary étendue, flat primary objective with a relaxed figure tolerance, gossamer membrane substrate stowable as an unsegmented roll inside a delivery vehicle, and extensibility past 100 meter aperture at optical wavelengths. The novel design meets many criteria for space deployment. Other embodiments are suitable for airborne platforms as well as terrestrial and lunar sites. One problem with this novel telescope is that the grazing exodus configuration necessary to achieve a large aperture is traded for throughput efficiency. Now we show how the hologram of a point source used in place of the primary objective plane grating can improve efficiency by lowering the diffraction angle below grazing exodus. An intermediate refractive element is used to compensate for wavelength dependent focal lengths of the holographic primary objective.
Understanding the holographic principle via RG flow
NASA Astrophysics Data System (ADS)
Mukhopadhyay, Ayan
2016-12-01
This is a review of some recent works which demonstrate how the classical equations of gravity in AdS themselves hold the key to understand their holographic origin in the form of a strongly coupled large N QFT whose algebra of local operators can be generated by a few (single-trace) elements. I discuss how this can be realized by reformulating Einstein’s equations in AdS in the form of a nonperturbative RG flow that further leads to a new approach toward constructing strongly interacting QFTs. In particular, the RG flow can self-determine the UV data that are otherwise obtained by solving classical gravity equations and demanding that the solutions do not have naked singularities. For a concrete demonstration, I focus on the hydrodynamic limit in which case this RG flow connects the AdS/CFT correspondence with the membrane paradigm, and also reproduces the known values of the dual QFT transport coefficients.
3D holographic portraits: presence and absence
NASA Astrophysics Data System (ADS)
Oliveria, Rosa M.; Bernardo, Luís Miguel
2011-02-01
Authors writing about the portrait insist on the status of extending the model image portrayed beyond the absence and even death. The portrait also has this ability and suggests immortality. The picture suspends the time, making the absent present. The portrait has been, over time, one of the themes mostly used in art. No wonder that in holography it is an important subject as well. The face is a body area of privileged communication and expression. It expresses emotions through looks, smiles, movements and expressions. Being Holography, so far, the recording technology that represents the object most similar to the original, with the same parallax, we may fall into a mimetic representation of reality. On Art Holography even by following paths already traversed, the resulting holograms are always different because of the unique concept that each artist-holographer puts into his work. As with any other artistic technology, each artist uses the medium differently and with different results.
Real-time color holographic interferometry
NASA Astrophysics Data System (ADS)
Desse, Jean-Michel; Albe, Felix; Tribillon, Jean-Louis
2002-09-01
A new optical technique based on real-time color holographic interferometry has been developed for analyzing unsteady aerodynamic wakes in fluid mechanics or for measuring displacements and deformations in solid mechanics. The technique's feasibility is demonstrated here. It uses three coherent wavelengths produced simultaneously by a cw laser (mixed argon and krypton). Holograms are recorded on single-layer panchromatic silver halide (Slavich PFG 03C) plates. Results show the optical setup can be adjusted to obtain a uniform background color. The interference fringe pattern visualized is large and colored and exhibits a single central white fringe, which makes the zero order of the interferogram easy to identify. An application in a subsonic wind tunnel is presented, in which the unsteady wake past a cylinder is recorded at high rate.
Real-time color holographic interferometry.
Desse, Jean-Michel; Albe, Félix; Tribillon, Jean-Louis
2002-09-01
A new optical technique based on real-time color holographic interferometry has been developed for analyzing unsteady aerodynamic wakes in fluid mechanics or for measuring displacements and deformations in solid mechanics. The technique's feasibility is demonstrated here. It uses three coherent wavelengths produced simultaneously by a cw laser (mixed argon and krypton). Holograms are recorded on single-layer panchromatic silver halide (Slavich PFG 03C) plates. Results show the optical setup can be adjusted to obtain a uniform background color. The interference fringe pattern visualized is large and colored and exhibits a single central white fringe, which makes the zero order of the interferogram easy to identify. An application in a subsonic wind tunnel is presented, in which the unsteady wake past a cylinder is recorded at high rate.
Towards a Holographic Marginal Fermi Liquid
Jensen, Kristan; Kachru, Shamit; Karch, Andreas; Polchinski, Joseph; Silverstein, Eva
2011-08-15
We present an infinite class of 2+1 dimensional field theories which, after coupling to semi-holographic fermions, exhibit strange metallic behavior in a suitable large N limit. These theories describe lattices of hypermultiplet defects interacting with parity-preserving supersymmetric Chern-Simons theories with U(N) x U(N) gauge groups at levels {+-}k. They have dual gravitational descriptions in terms of lattices of probe M2 branes in AdS{sub 4} x S{sup 7}/Z{sub k} (for N >> 1,N >> k{sup 5}) or probe D2 branes in AdS{sub 4} x CP{sup 3} (for N >> k >> 1,N << k{sup 5}). We discuss several challenges one faces in maintaining the success of these models at finite N, including backreaction of the probes in the gravity solutions and radiative corrections in the weakly coupled field theory limit.
A laser module for holographic data storage
NASA Astrophysics Data System (ADS)
Ensher, Jason; Wegner, Aaron; Cozakos, Jason; Mandeville, Richard
2010-06-01
InPhase Technologies is developing a holographic data storage drive with a target lifetime of at least 10 years. The laser light source is a key component of the drive. Based on the limited lifetimes of early blue laser diodes, we made the laser a modular and replaceable unit to minimize drive downtime and insure that the overall HDS drive meets the long lifetime goal. Previously, we reported on one part of the laser module, the blue external cavity diode laser (ECLD) that we co-developed with Nichia Corporation [1]. In this paper we report on the rest of the laser module, which prepares coherent, wavelength tunable light from the ECLD for insertion into an HDS drive.
Speckle-field digital holographic microscopy
Park, YongKeun; Choi, Wonshik; Yaqoob, Zahid; Dasari, Ramachandra; Badizadegan, Kamran; Feld, Michael S.
2010-01-01
The use of coherent light in conventional holographic phase microscopy (HPM) poses three major drawbacks: poor spatial resolution, weak depth sectioning, and fixed pattern noise due to unwanted diffraction. Here, we report a technique which can overcome these drawbacks, but maintains the advantage of phase microscopy - high contrast live cell imaging and 3D imaging. A speckle beam of a complex spatial pattern is used for illumination to reduce fixed pattern noise and to improve optical sectioning capability. By recording of the electric field of speckle, we demonstrate high contrast 3D live cell imaging without the need for axial scanning - neither objective lens nor sample stage. This technique has great potential in studying biological samples with improved sensitivity, resolution and optical sectioning capability. PMID:19654630
Higher derivative corrections in holographic QCD
Basu, Anirban
2007-12-15
We consider the effect of the R{sup 4} term in type IIA string theory on the supergravity background dual to N{sub c} D4-branes compactified on a circle with supersymmetry breaking boundary conditions. We study the dynamics of D8-branes in this perturbed geometry in the probe approximation. This leads to an analysis of higher derivative corrections in holographic QCD beyond the supergravity approximation. We make a rough estimate of the corrections to the masses of some of the lightest (axial) vector mesons. The corrections are suppressed by a factor of (g{sub YM}{sup 2}N{sub c}){sup -3} compared to their supergravity values. We find that the masses of these mesons increase from their supergravity values.
NASA Astrophysics Data System (ADS)
Burch, Benjamin P.
The precise phase-space distribution and properties of Galactic dark matter necessary for its direct and indirect detection are currently unknown. Since the distributions of normal and dark matter in the Milky Way are coupled to each other as they both move in the same gravitational potential, constraints on the distribution and properties of dark matter can be derived by studying the distribution of visible matter in the Galaxy and making some general assumptions regarding the phase-space distribution of the dark matter. In this study, the visible components of the Galaxy have been comprehensively reviewed to create an axisymmetric model of the Galaxy that is consistent with the available observations, and the dark matter phase-space distribution is assumed to follow a lowered-isothermal form. Poisson's equations are then solved self-consistently to construct models of the spatial and velocity distribution of Galactic dark matter. The total gravitational potential from normal and dark matter are calculated and compared to the current observations of the rotation curve and to the radial velocity distributions of blue horizontal-branch and blue straggler stars. It is found that this analysis allows for a wide range of parameters for the dark matter. The implications for direct and indirect detection of dark matter are discussed in detail. In the appendices, two additional projects are presented. In Appendix A, the recent observations of the positron fraction and the total electron spectrum in cosmic rays are addressed by considering a nested leaky-box model for the propagation of cosmic rays in the Galaxy. This is found to obviate the need for exotic processes such as the annihilation or decay of dark matter to explain the recent observations. In Appendix B, we discuss a novel dark matter detector involving triggered cavitation in acoustic fields. The theory behind the detector is presented in detail, and we discuss the work than has been done to create a prototype
NASA Astrophysics Data System (ADS)
Cvetič, Mirjam; Papadimitriou, Ioannis
2016-12-01
We construct the holographic dictionary for both running and constant dilaton solutions of the two dimensional Einstein-Maxwell-Dilaton theory that is obtained by a circle reduction from Einstein-Hilbert gravity with negative cosmological constant in three dimensions. This specific model ensures that the dual theory has a well defined ultraviolet completion in terms of a two dimensional conformal field theory, but our results apply qualitatively to a wider class of two dimensional dilaton gravity theories. For each type of solutions we perform holographic renormalization, compute the exact renormalized one-point functions in the presence of arbitrary sources, and derive the asymptotic symmetries and the corresponding conserved charges. In both cases we find that the scalar operator dual to the dilaton plays a crucial role in the description of the dynamics. Its source gives rise to a matter conformal anomaly for the running dilaton solutions, while its expectation value is the only non trivial observable for constant dilaton solutions. The role of this operator has been largely overlooked in the literature. We further show that the only non trivial conserved charges for running dilaton solutions are the mass and the electric charge, while for constant dilaton solutions only the electric charge is non zero. However, by uplifting the solutions to three dimensions we show that constant dilaton solutions can support non trivial extended symmetry algebras, including the one found by Compère, Song and Strominger [1], in agreement with the results of Castro and Song [2]. Finally, we demonstrate that any solution of this specific dilaton gravity model can be uplifted to a family of asymptotically AdS2 × S 2 or conformally AdS2 × S 2 solutions of the STU model in four dimensions, including non extremal black holes. The four dimensional solutions obtained by uplifting the running dilaton solutions coincide with the so called `subtracted geometries', while those obtained
Experimental research of digital holographic microscopic measuring
NASA Astrophysics Data System (ADS)
Zhu, Xueliang; Chen, Feifei; Li, Jicheng
2013-06-01
Digital holography is a new imaging technique, which is developed on the base of optical holography, Digital processing, and Computer techniques. It is using CCD instead of the conventional silver to record hologram, and then reproducing the 3D contour of the object by the way of computer simulation. Compared with the traditional optical holographic, the whole process is of simple measuring, lower production cost, faster the imaging speed, and with the advantages of non-contact real-time measurement. At present, it can be used in the fields of the morphology detection of tiny objects, micro deformation analysis, and biological cells shape measurement. It is one of the research hot spot at home and abroad. This paper introduced the basic principles and relevant theories about the optical holography and Digital holography, and researched the basic questions which influence the reproduce images in the process of recording and reconstructing of the digital holographic microcopy. In order to get a clear digital hologram, by analyzing the optical system structure, we discussed the recording distance and of the hologram. On the base of the theoretical studies, we established a measurement and analyzed the experimental conditions, then adjusted them to the system. To achieve a precise measurement of tiny object in three-dimension, we measured MEMS micro device for example, and obtained the reproduction three-dimensional contour, realized the three dimensional profile measurement of tiny object. According to the experiment results consider: analysis the reference factors between the zero-order term and a pair of twin-images by the choice of the object light and the reference light and the distance of the recording and reconstructing and the characteristics of reconstruction light on the measurement, the measurement errors were analyzed. The research result shows that the device owns certain reliability.
Synfograms: a new generation of holographic applications
NASA Astrophysics Data System (ADS)
Meulien Öhlmann, Odile; Öhlmann, Dietmar; Zacharovas, Stanislovas J.
2008-04-01
The new synthetic Four-dimensional printing technique (Syn4D) Synfogram is introducing time (animation) into spatial configuration of the imprinted three-dimensional shapes. While lenticular solutions offer 2 to 9 stereoscopic images Syn4D offers large format, full colors true 3D visualization printing of 300 to 2500 frames imprinted as holographic dots. This past 2 years Syn4D high-resolution displays proved to be extremely efficient for museums presentation, engineering design, automobile prototyping, and advertising virtual presentation as well as, for portrait and fashion applications. The main advantages of syn4D is that it offers a very easy way of using a variety of digital media, like most of 3D Modelling programs, 3D scan system, video sequences, digital photography, tomography as well as the Syn4D camera track system for life recording of spatial scenes changing in time. The use of digital holographic printer in conjunction with Syn4D image acquiring and processing devices separates printing and imaging creation in such a way that makes four-dimensional printing similar to a conventional digital photography processes where imaging and printing are usually separated in space and time. Besides making content easy to prepare, Syn4D has also developed new display and lighting solutions for trade show, museum, POP, merchandising, etc. The introduction of Synfograms is opening new applications for real life and virtual 4D displays. In this paper we will analyse the 3D market, the properties of the Synfograms and specific applications, the problems we encounter, solutions we find, discuss about customers demand and need for new product development.
NASA Astrophysics Data System (ADS)
Dhuria, Mansi; Misra, Aalok
2012-02-01
We show that it is possible to realize a " μ-split SUSY" scenario (Cheng and Cheng, 2005) [1] in the context of large volume limit of type IIB compactifications on Swiss-cheese Calabi-Yau orientifolds in the presence of a mobile space-time filling D3-brane and a (stack of) D7-brane(s) wrapping the "big" divisor. For this, we investigate the possibility of getting one Higgs to be light while other to be heavy in addition to a heavy higgsino mass parameter. Further, we examine the existence of long lived gluino that manifests one of the major consequences of μ-split SUSY scenario, by computing its decay width as well as lifetime corresponding to the three-body decays of the gluino into either a quark, a squark and a neutralino or a quark, squark and goldstino, as well as two-body decays of the gluino into either a neutralino and a gluon or a goldstino and a gluon. Guided by the geometric Kähler potential for Σ obtained in Misra and Shukla (2010) [2] based on GLSM techniques, and the Donaldson's algorithm (Barun et al., 2008) [3] for obtaining numerically a Ricci-flat metric, we give details of our calculation in Misra and Shukla (2011) [4] pertaining to our proposed metric for the full Swiss-cheese Calabi-Yau (the geometric Kähler potential being needed to be included in the full moduli space Kähler potential in the presence of the mobile space-time filling D3-brane), but for simplicity of calculation, close to the big divisor, which is Ricci-flat in the large volume limit. Also, as an application of the one-loop RG flow solution for the higgsino mass parameter, we show that the contribution to the neutrino masses at the EW scale from dimension-six operators arising from the Kähler potential, is suppressed relative to the Weinberg-type dimension-five operators.
Dark microglia: Why are they dark?
Bisht, Kanchan; Sharma, Kaushik; Lacoste, Baptiste; Tremblay, Marie-Ève
2016-01-01
ABSTRACT Using transmission electron microscopy (TEM) we recently characterized a microglial phenotype that is induced by chronic stress, fractalkine receptor deficiency, aging, or Alzheimer disease pathology. These ‘dark’ microglia appear overly active compared with the normal microglia, reaching for synaptic clefts, and extensively engulfing pre-synaptic axon terminals and post-synaptic dendritic spines. From these findings we hypothesized that dark microglia could be specifically implicated in the pathological remodeling of neuronal circuits, which impairs learning, memory, and other essential cognitive functions. In the present addendum we further discuss about the possible causes of their dark appearance under TEM. PMID:28042375
Li, X.Y.; Harko, T.; Cheng, K.S. E-mail: harko@hkucc.hku.hk
2012-06-01
We investigate the structure and stability properties of compact astrophysical objects that may be formed from the Bose-Einstein condensation of dark matter. Once the critical temperature of a boson gas is less than the critical temperature, a Bose-Einstein Condensation process can always take place during the cosmic history of the universe. Therefore we model the dark matter inside the star as a Bose-Einstein condensate. In the condensate dark matter star model, the dark matter equation of state can be described by a polytropic equation of state, with polytropic index equal to one. We derive the basic general relativistic equations describing the equilibrium structure of the condensate dark matter star with spherically symmetric static geometry. The structure equations of the condensate dark matter stars are studied numerically. The critical mass and radius of the dark matter star are given by M{sub crit} ≈ 2(l{sub a}/1fm){sup 1/2}(m{sub χ}/1 GeV){sup −3/2}M{sub s}un and R{sub crit} ≈ 1.1 × 10{sup 6}(l{sub a}/1 fm){sup 1/2}(m{sub χ}/1 GeV){sup −3/2} cm respectively, where l{sub a} and m{sub χ} are the scattering length and the mass of dark matter particle, respectively.
ERIC Educational Resources Information Center
Weston, Anthony
2014-01-01
Environmentalism's wider and wilder possibilities today appear as regions of seeming darkness that bracket or frame acceptable environmental thinking. One of these barely-mentionable darknesses is outer space--the cosmos. Another is the inner and chthonic powers of the land and natural beings generally. This essay aims to bring these two kinds of…
Professor Sean Carroll
2016-07-12
General relativity is inconsistent with cosmological observations unless we invoke components of dark matter and dark energy that dominate the universe. While it seems likely that these exotic substances really do exist, the alternative is worth considering: that Einstein's general relativity breaks down on cosmological scales. I will discuss models of modified gravity, tests in the solar system and elsewhere, and consequences for cosmology.
NASA Technical Reports Server (NTRS)
Liu, H. K.
1976-01-01
The techniques of speckle beam holographic interferometry and speckle photographic interferometry are described. In particular, their practical limitations and their applications to the existing holographic nondestructive test system are discussed.
High-speed high-density holographic memory using electro-optic beam steering devices
NASA Astrophysics Data System (ADS)
Chao, Tien-Hsin; Zhou, Hanying; Reyes, George F.; Dragoi, Danut; Hanan, Jay
2002-11-01
An innovative compact holographic memory system will be presented. This system utilizes a new electro-optic (E-O) beam steering technology to achieve high-speed, high-density holographic data storage.
Some recent advances in the bottom-up holographic approach to QCD
Afonin, S. S.
2014-07-23
We give a brief report on our recent results in the bottom-up holographic approach to QCD. The holographic description of the heavy vector quarkonia and generalization of the Soft Wall model are discussed.
Dark matter and dark energy: The critical questions
Michael S. Turner
2002-11-19
Stars account for only about 0.5% of the content of the Universe; the bulk of the Universe is optically dark. The dark side of the Universe is comprised of: at least 0.1% light neutrinos; 3.5% {+-} 1% baryons; 29% {+-} 4% cold dark matter; and 66% {+-} 6% dark energy. Now that we have characterized the dark side of the Universe, the challenge is to understand it. The critical questions are: (1) What form do the dark baryons take? (2) What is (are) the constituent(s) of the cold dark matter? (3) What is the nature of the mysterious dark energy that is causing the Universe to speed up.
Static structures of the BCS-like holographic superfluid in AdS4 spacetime
NASA Astrophysics Data System (ADS)
Lan, Shanquan; Liu, Wenbiao; Tian, Yu
2017-03-01
We investigate in detail the m2=0 Abelian Higgs model in AdS4 , which is considered as the holographic dual of the most BCS-like superfluid. In homogeneous and isotropic superfluid solutions, we calculate the fourth-sound speeds, the square of which approaches 1 /2 with increasing chemical potential (lowering temperature). Then we present the single dark soliton solutions, which becomes thinner with increasing chemical potential. For the first time, we also find the interesting double and triple dark soliton solutions, which is unexpected and shows the possibility of more complicated static configurations. Finally, we investigate vortex solutions. For winding number n =1 , the vortex becomes thinner with increasing chemical potential. At a given chemical potential, with increasing winding number, first the vortex becomes bigger and the charge density depletion becomes larger, and then the charge density depletion settles down at a certain value and the growth of the vortex size is found to obey a scaling symmetry.
Sapone, Domenico; Kunz, Martin
2009-10-15
Dark energy perturbations are normally either neglected or else included in a purely numerical way, obscuring their dependence on underlying parameters like the equation of state or the sound speed. However, while many different explanations for the dark energy can have the same equation of state, they usually differ in their perturbations so that these provide a fingerprint for distinguishing between different models with the same equation of state. In this paper we derive simple yet accurate approximations that are able to characterize a specific class of models (encompassing most scalar-field models) which is often generically called 'dark energy'. We then use the approximate solutions to look at the impact of the dark energy perturbations on the dark matter power spectrum and on the integrated Sachs-Wolfe effect in the cosmic microwave background radiation.
Sol-Gel Glass Holographic Light-Shaping Diffusers
NASA Technical Reports Server (NTRS)
Yu, Kevin; Lee, Kang; Savant, Gajendra; Yin, Khin Swe (Lillian)
2005-01-01
Holographic glass light-shaping diffusers (GLSDs) are optical components for use in special-purpose illumination systems (see figure). When properly positioned with respect to lamps and areas to be illuminated, holographic GLSDs efficiently channel light from the lamps onto specified areas with specified distributions of illumination for example, uniform or nearly uniform irradiance can be concentrated with intensity confined to a peak a few degrees wide about normal incidence, over a circular or elliptical area. Holographic light diffusers were developed during the 1990s. The development of the present holographic GLSDs extends the prior development to incorporate sol-gel optical glass. To fabricate a holographic GLSD, one records a hologram on a sol-gel silica film formulated specially for this purpose. The hologram is a quasi-random, micro-sculpted pattern of smoothly varying changes in the index of refraction of the glass. The structures in this pattern act as an array of numerous miniature lenses that refract light passing through the GLSD, such that the transmitted light beam exhibits a precisely tailored energy distribution. In comparison with other light diffusers, holographic GLSDs function with remarkably high efficiency: they typically transmit 90 percent or more of the incident lamp light onto the designated areas. In addition, they can withstand temperatures in excess of 1,000 C. These characteristics make holographic GLSDs attractive for use in diverse lighting applications that involve high temperatures and/or requirements for high transmission efficiency for ultraviolet, visible, and near-infrared light. Examples include projectors, automobile headlights, aircraft landing lights, high-power laser illuminators, and industrial and scientific illuminators.
Complex Nanoscale-Ordered Liquid Crystal Polymer Film for High Transmittance Holographic Polarizer.
Du, Tao; Fan, Fan; Tam, Alwin Ming Wai; Sun, Jiatong; Chigrinov, Vladimir G; Sing Kwok, Hoi
2015-11-25
A special design of a complex-ordered liquid crystal polymer film is developed into a holographic polarizer. The holographic polarizer shows over 90% transmittance, which provides a simple solution to make LEDs polarized. Furthermore, the holographic polarizer exhibits intensity and polarization maintenance properties, which could be further developed for photonics applications.
Pseudoscalar portal dark matter
NASA Astrophysics Data System (ADS)
Berlin, Asher; Gori, Stefania; Lin, Tongyan; Wang, Lian-Tao
2015-07-01
A fermion dark matter candidate with a relic abundance set by annihilation through a pseudoscalar can evade constraints from direct detection experiments. We present simplified models that realize this fact by coupling a fermion dark sector to a two-Higgs doublet model. These models are generalizations of mixed bino-Higgsino dark matter in the minimal supersymmetric standard model, with more freedom in the couplings and scalar spectra. Annihilation near a pseudoscalar resonance allows a significant amount of parameter space for thermal relic dark matter compared to singlet-doublet dark matter, in which the fermions couple only to the standard model (SM) Higgs doublet. In a general two-Higgs doublet model, there is also freedom for the pseudoscalar to be relatively light and it is possible to obtain thermal relic dark matter candidates even below 100 GeV. In particular, we find ample room to obtain dark matter with mass around 50 GeV and fitting the Galactic center excess in gamma-rays. This region of parameter space can be probed by LHC searches for heavy pseudoscalars or electroweakinos, and possibly by other new collider signals.
Large Aperture Scanning Lidar Based on Holographic Optical Elements
NASA Technical Reports Server (NTRS)
Schwemmer, Geary K.; Miller, David O.; Wilkerson, Thomas D.; Andrus, Ionio; Guerra, David V.; Einaudi, Franco (Technical Monitor)
2001-01-01
Lidar remote sensing instruments can make a significant contribution to satisfying many of the required measurements of atmospheric and surface parameters for future spaceborne platforms, including topographic altimeters, atmospheric profiles of, wind, humidity, temperature, trace molecules, aerosols, and clouds. It is highly desirable to have wide measurement swaths for rapid coverage rather than just the narrow ribbon of data that is obtained with a nadir only observation. For most applications global coverage is required, and for wind measurements scanning or pointing is required in order to retrieve the full 3-D wind vector from multiple line-of-sight Doppler measurements. Conventional lidar receivers make up a substantial portion of the instrument's size and weight. Wide angle scanning typically requires a large scanning mirror in front of the receiver telescope, or pointing the entire telescope and aft optics assembly, Either of these methods entails the use of large bearings, motors, gearing and their associated electronics. Spaceborne instruments also need reaction wheels to counter the torque applied to the spacecraft by these motions. NASA has developed simplified conical scanning telescopes using Holographic Optical Elements (HOEs) to reduce the size, mass, angular momentum, and cost of scanning lidar systems. NASA has developed two operating lidar systems based on 40 cm diameter HOEs. The first such system, named Prototype Holographic Atmospheric Scanner for Environmental Remote Sensing (PHASERS) was a joint development between NASA Goddard Space Flight Center (GSFC) and the University of Maryland College Park. PHASERS is based on a reflection HOE for use at the doubled Nd:YAG laser wavelength of 532 nm and has recently undergone a number of design changes in a collaborative effort between GSFC and Saint Anselm College in New Hampshire. The next step was to develop IR transmission HOEs for use with the Nd:YAG fundamental in the Holographic Airborne
Holographic Reflection Filters in Photorefractive LiNbO3 Channel Waveguides
NASA Astrophysics Data System (ADS)
Kip, Detlef; Hukriede, Joerg
Permanent refractive-index gratings in waveguide devices are of considerable interest for optical communication systems that make use of the high spectral selectivity of holographic filters, e.g. dense wavelength division multiplexing (DWDM) or narrow-bandwidth mirrors for integrated waveguide lasers in LiNbO3. Other possible applications include grating couplers and optical sensors. In this contribution we investigate such holographic wavelength filters in Fe- and Cu-doped LiNbO3 channel waveguides. Permanent refractive-index gratings are generated by thermal fixing of holograms in the waveguides. The samples are fabricated by successive in-diffusion of Ti stripes and thin layers of either Fe or Cu. After high-temperature recording with green light, refractive-index changes up to δ, ~10^-4 for infrared light ( 1.55,m) are obtained, resulting in a reflection efficiency well above 99% for a 15 mm-long grating. Several gratings for different wavelengths can be superimposed in the same sample, which may enable the fabrication of more complex filters, laser mirrors or optical sensors. By changing the sample temperature the reflection wavelength can be tuned by thermal expansion of the grating, and wavelength filters can be switched on and off by applying moderate voltages using the electro-optic effect. Furthermore, we report on a new thermal fixing mechanism that does not need any additional development by homogeneous light illumination and therefore does not suffer from the non-vanishing dark conductivity of the material.
NASA Astrophysics Data System (ADS)
Ogaz, Sara
2013-10-01
This takes a series of SBC dark measurements over a continuous period of about 6 hours {4 orbits}. The aim is to collect dark images during an extended SBC on-time. Earlier measurements indicate that the dark current increases with SBC on-time and may also be increasing with overall SBC use. The 6-hour time matches the longest time used by any observer. As with all SBC observations this needs continuous SAA free time.This program is executed once per cycle. The last exposures were taken in Mar 2013 under Program 13161.
NASA Astrophysics Data System (ADS)
Fong, Richard; Doroshkevich, Andrei G.; Turchaninov, Victor I.
1995-07-01
The theory of the formation of large-scale structure in the universe through the action of gravitational instability imply the existence of substantial amounts of baryonic dark matter, of the order of 50% of the total baryon content in the universe, in the ``voids'' or under-dense regions seen in the large-scale distribution of galaxies. We discuss also the large-scale structure of dark matter expected in voids and the present and future possibilities for the observation of this baryonic dark matter in ``voids.''
NASA Technical Reports Server (NTRS)
2006-01-01
As winter turns to spring at the south polar ice cap of Mars, the rising sun reveals dark spots and fans emerging from the cold polar night. Using visual images (left) and temperature data (right) from the Thermal Emission Imaging system on NASA's Mars Odyssey orbiter, scientists have built a new model for the origin of the dark markings. Scientists propose the markings come from dark sand and dust strewn by high-speed jets of carbon-dioxide gas. These erupt from under a layer of carbon-dioxide ice that forms each Martian winter.
Pattern-Recognition Processor Using Holographic Photopolymer
NASA Technical Reports Server (NTRS)
Chao, Tien-Hsin; Cammack, Kevin
2006-01-01
proposed joint-transform optical correlator (JTOC) would be capable of operating as a real-time pattern-recognition processor. The key correlation-filter reading/writing medium of this JTOC would be an updateable holographic photopolymer. The high-resolution, high-speed characteristics of this photopolymer would enable pattern-recognition processing to occur at a speed three orders of magnitude greater than that of state-of-the-art digital pattern-recognition processors. There are many potential applications in biometric personal identification (e.g., using images of fingerprints and faces) and nondestructive industrial inspection. In order to appreciate the advantages of the proposed JTOC, it is necessary to understand the principle of operation of a conventional JTOC. In a conventional JTOC (shown in the upper part of the figure), a collimated laser beam passes through two side-by-side spatial light modulators (SLMs). One SLM displays a real-time input image to be recognized. The other SLM displays a reference image from a digital memory. A Fourier-transform lens is placed at its focal distance from the SLM plane, and a charge-coupled device (CCD) image detector is placed at the back focal plane of the lens for use as a square-law recorder. Processing takes place in two stages. In the first stage, the CCD records the interference pattern between the Fourier transforms of the input and reference images, and the pattern is then digitized and saved in a buffer memory. In the second stage, the reference SLM is turned off and the interference pattern is fed back to the input SLM. The interference pattern thus becomes Fourier-transformed, yielding at the CCD an image representing the joint-transform correlation between the input and reference images. This image contains a sharp correlation peak when the input and reference images are matched. The drawbacks of a conventional JTOC are the following: The CCD has low spatial resolution and is not an ideal square
Holographic data storage: science fiction or science fact?
NASA Astrophysics Data System (ADS)
Anderson, Ken; Ayres, Mark; Askham, Fred; Sissom, Brad
2014-09-01
To compete in the archive and backup industries, holographic data storage must be highly competitive in four critical areas: total cost of ownership (TCO), cost/TB, capacity/footprint, and transfer rate. New holographic technology advancements by Akonia Holographics have enabled the potential for ultra-high capacity holographic storage devices that are capable of world record bit densities of over 2-4Tbit/in2, up to 200MB/s transfer rates, and media costs less than $10/TB in the next few years. Additional advantages include more than a 3x lower TCO than LTO, a 3.5x decrease in volumetric footprint, 30ms random access times, and 50 year archive life. At these bit densities, 4.5 Petabytes of uncompressed user data could be stored in a 19" rack system. A demonstration platform based on these new advances has been designed and built by Akonia to progressively demonstrate bit densities of 2Tb/in2, 4Tb/in2, and 8Tb/in2 over the next year. Keywords: holographic
Demosaiced pixel super-resolution for multiplexed holographic color imaging
NASA Astrophysics Data System (ADS)
Wu, Yichen; Zhang, Yibo; Luo, Wei; Ozcan, Aydogan
2016-06-01
To synthesize a holographic color image, one can sequentially take three holograms at different wavelengths, e.g., at red (R), green (G) and blue (B) parts of the spectrum, and digitally merge them. To speed up the imaging process by a factor of three, a Bayer color sensor-chip can also be used to demultiplex three wavelengths that simultaneously illuminate the sample and digitally retrieve individual set of holograms using the known transmission spectra of the Bayer color filters. However, because the pixels of different channels (R, G, B) on a Bayer color sensor are not at the same physical location, conventional demosaicing techniques generate color artifacts in holographic imaging using simultaneous multi-wavelength illumination. Here we demonstrate that pixel super-resolution can be merged into the color de-multiplexing process to significantly suppress the artifacts in wavelength-multiplexed holographic color imaging. This new approach, termed Demosaiced Pixel Super-Resolution (D-PSR), generates color images that are similar in performance to sequential illumination at three wavelengths, and therefore improves the speed of holographic color imaging by 3-fold. D-PSR method is broadly applicable to holographic microscopy applications, where high-resolution imaging and multi-wavelength illumination are desired.
Holographic display system for restoration of sight to the blind
Goetz, G A; Mandel, Y; Manivanh, R; Palanker, D V; Čižmár, T
2013-01-01
Objective We present a holographic near-the-eye display system enabling optical approaches for sight restoration to the blind, such as photovoltaic retinal prosthesis, optogenetic and other photoactivation techniques. We compare it with conventional LCD or DLP-based displays in terms of image quality, field of view, optical efficiency and safety. Approach We detail the optical configuration of the holographic display system and its characterization using a phase-only spatial light modulator. Main results We describe approaches to controlling the zero diffraction order and speckle related issues in holographic display systems and assess the image quality of such systems. We show that holographic techniques offer significant advantages in terms of peak irradiance and power efficiency, and enable designs that are inherently safer than LCD or DLP-based systems. We demonstrate the performance of our holographic display system in the assessment of cortical response to alternating gratings projected onto the retinas of rats. Significance We address the issues associated with the design of high brightness, near-the-eye display systems and propose solutions to the efficiency and safety challenges with an optical design which could be miniaturized and mounted onto goggles. PMID:24045579
Holographic display system for restoration of sight to the blind
NASA Astrophysics Data System (ADS)
Goetz, G. A.; Mandel, Y.; Manivanh, R.; Palanker, D. V.; Čižmár, T.
2013-10-01
Objective. We present a holographic near-the-eye display system enabling optical approaches for sight restoration to the blind, such as photovoltaic retinal prosthesis, optogenetic and other photoactivation techniques. We compare it with conventional liquid crystal displays (LCD) or digital light processing (DLP)-based displays in terms of image quality, field of view, optical efficiency and safety. Approach. We detail the optical configuration of the holographic display system and its characterization using a phase-only spatial light modulator. Main results. We describe approaches to controlling the zero diffraction order and speckle related issues in holographic display systems and assess the image quality of such systems. We show that holographic techniques offer significant advantages in terms of peak irradiance and power efficiency, and enable designs that are inherently safer than LCD or DLP-based systems. We demonstrate the performance of our holographic display system in the assessment of cortical response to alternating gratings projected onto the retinas of rats. Significance. We address the issues associated with the design of high brightness, near-the-eye display systems and propose solutions to the efficiency and safety challenges with an optical design which could be miniaturized and mounted onto goggles.
Lensfree holographic imaging for on-chip cytometry and diagnostics.
Seo, Sungkyu; Su, Ting-Wei; Tseng, Derek K; Erlinger, Anthony; Ozcan, Aydogan
2009-03-21
We experimentally illustrate a lensfree holographic imaging platform to perform on-chip cytometry. By controlling the spatial coherence of the illumination source, we record a 2D holographic diffraction pattern of each cell or micro-particle on a chip using a high resolution sensor array that has approximately 2 microm pixel size. The recorded holographic image is then processed by using a custom developed decision algorithm for matching the detected hologram texture to existing library images for on-chip characterization and counting of a heterogeneous solution of interest. The holographic diffraction signature of any microscopic object is significantly different from the classical diffraction pattern of the same object. It improves the signal to noise ratio and the signature uniformity of the cell patterns; and also exhibits much better sensitivity for on-chip imaging of weakly scattering phase objects such as small bacteria or cells. We verify significantly improved performance of this holographic on-chip cytometry approach by automatically characterizing heterogeneous solutions of red blood cells, yeast cells, E. coli and various sized micro-particles without the use of any lenses or microscope objectives. This lensless on-chip holography platform will especially be useful for point-of-care cytometry and diagnostics applications involving e.g., infectious diseases such as HIV or malaria.
Demosaiced pixel super-resolution for multiplexed holographic color imaging
Wu, Yichen; Zhang, Yibo; Luo, Wei; Ozcan, Aydogan
2016-01-01
To synthesize a holographic color image, one can sequentially take three holograms at different wavelengths, e.g., at red (R), green (G) and blue (B) parts of the spectrum, and digitally merge them. To speed up the imaging process by a factor of three, a Bayer color sensor-chip can also be used to demultiplex three wavelengths that simultaneously illuminate the sample and digitally retrieve individual set of holograms using the known transmission spectra of the Bayer color filters. However, because the pixels of different channels (R, G, B) on a Bayer color sensor are not at the same physical location, conventional demosaicing techniques generate color artifacts in holographic imaging using simultaneous multi-wavelength illumination. Here we demonstrate that pixel super-resolution can be merged into the color de-multiplexing process to significantly suppress the artifacts in wavelength-multiplexed holographic color imaging. This new approach, termed Demosaiced Pixel Super-Resolution (D-PSR), generates color images that are similar in performance to sequential illumination at three wavelengths, and therefore improves the speed of holographic color imaging by 3-fold. D-PSR method is broadly applicable to holographic microscopy applications, where high-resolution imaging and multi-wavelength illumination are desired. PMID:27353242
Environmental stability study of holographic solar spectrum splitting materials
NASA Astrophysics Data System (ADS)
Chrysler, Benjamin D.; Ayala Pelaez, Silvana; Wu, Yuechen; Vorndran, Shelby D.; Kostuk, Raymond K.
2016-09-01
In this study the impact of outdoor temperature variations and solar illumination exposure on spectral filter material and holographic optical elements is examined. Although holographic components have been shown to be useful for solar spectrum splitting designs, relatively little quantitative data exist to demonstrate the extent to which these materials can withstand outdoor conditions. As researchers seek to investigate practical spectrum splitting designs, the environmental stability of holographic materials should be considered as an important factor. In the experiment presented, two holographic materials, Covestro Bayfol HX photopolymer and dichromated gelatin, and 3M reflective polymer filter materials are exposed to outdoor conditions for a period of several months. The environmental effect on absorption, spectral and angular bandwidth, peak efficiency, and Bragg matching conditions for the holograms are examined. Spectral bandwidth and transmittance of the 3M reflective filter material are also monitored. Holographic gratings are recorded, measured, and mounted on glass substrates and then sealed with a glass cover plate. The test samples are then mounted on a photovoltaic panel to simulate realistic temperature conditions and placed at an outdoor test facility in Tucson, Arizona. A duplicate set of holograms and 3M filter material is stored as a control group and periodically compared over the test period.
Quantitative three-dimensional holographic interferometry for flow field analysis
NASA Astrophysics Data System (ADS)
Holden, C. M. E.; Parker, S. C. J.; Bryanston-Cross, P. J.
Holographic interferometry offers the potential for quantitative, wholefield analysis of three-dimensional compressible flows. The technique is non-intrusive, does not require the introduction of seeding particles, and records the entire flow information within the pulse duration of a Q-switched ruby laser (~30ns). At present, however, holographic interferometry is mainly used qualitatively due to the practical restrictions of data recording, acquisition and processing. To address the potential of holographic flow analysis a prototype multi-channel interferometer has been designed and preliminary wind tunnel results have been obtained. The proposed configuration uses specular illumination which, unlike comparable diffuse systems, does not suffer from fringe localisation and speckle noise. Beam collimation and steering through the flow field is achieved in a single operation by the use of holographic optical elements (HOEs). The resulting design is compact, light efficient, has aberration compensation, and the recorded data are conducive to both tomographic analysis and direct comparison to computational fluid dynamics (CFD) predictions. Holograms have been recorded of simple two-dimensional and axisymmetric compressible flows, to compare the accuracy of holographic density measurements with data from conventional pressure sensors and CFD codes. Data extraction from the holograms, and the elimination of rigid body motion, was achieved using digital Fourier transform fringe analysis. The introduction of phase errors by image processing has been investigated by analysing simulated fringe patterns generated from a combination of experimental amplitude information and computer generated phase data.
Modifications to holographic entanglement entropy in warped CFT
NASA Astrophysics Data System (ADS)
Song, Wei; Wen, Qiang; Xu, Jianfei
2017-02-01
In [1] it was observed that asymptotic boundary conditions play an important role in the study of holographic entanglement beyond AdS/CFT. In particular, the Ryu-Takayanagi proposal must be modified for warped AdS3 (WAdS3) with Dirichlet boundary conditions. In this paper, we consider AdS3 and WAdS3 with Dirichlet-Neumann boundary conditions. The conjectured holographic duals are warped conformal field theories (WCFTs), featuring a Virasoro-Kac-Moody algebra. We provide a holographic calculation of the entanglement entropy and Rényi entropy using AdS3/WCFT and WAdS3/WCFT dualities. Our bulk results are consistent with the WCFT results derived by Castro-Hofman-Iqbal using the Rindler method. Comparing with [1], we explicitly show that the holographic entanglement entropy is indeed affected by boundary conditions. Both results differ from the Ryu-Takayanagi proposal, indicating new relations between spacetime geometry and quantum entanglement for holographic dualities beyond AdS/CFT.
Photorefractive digital holographic microscopy applied in microstructures analysis
NASA Astrophysics Data System (ADS)
Brito, Isis V.; Gesualdi, Marcos R. R.; Ricardo, Jorge; Palácios, Francisco; Muramatsu, Mikiya; Valin, José L.
2013-01-01
In this work, we present a Photorefractive Digital Holographic Microscopy (PRDHM) technique based on the writing-reading holographic process in photorefractive Bi12TiO20 (BTO) crystal and the obtainment of phase and amplitude of the object wave were performed by a digital holographic method. We demonstrate that the wave diffracted by a photorefractive hologram recorded in a BTO crystal can be combined with a reference wave to record a second hologram in a CCD sensor in a configuration of digital holographic microscopy. The experimental measurements were performed on samples like red blood cells and a thin film structure, and were obtained quantitative values of amplitude and phase of the object wave, as well as 3D graphs, of the analyzed samples by the digital reconstruction holographic method. This technique presents a new method in replacement of the usual methods for reconstruction of holograms recorded in a photorefractive crystal and also presents the possibilities to obtain 3D phase images for surfaces characterization and applications in dynamic holography.
Non-Abelian dark matter and dark radiation
NASA Astrophysics Data System (ADS)
Buen-Abad, Manuel A.; Marques-Tavares, Gustavo; Schmaltz, Martin
2015-07-01
We propose a new class of dark matter models with unusual phenomenology. What is ordinary about our models is that dark matter particles are weakly interacting massive particles; they are weakly coupled to the standard model and have weak scale masses. What is unusual is that they come in multiplets of a new dark non-Abelian gauge group with milliweak coupling. The massless dark gluons of this dark gauge group contribute to the energy density of the Universe as a form of weakly self-interacting dark radiation. In this paper we explore the consequences of having (i) dark matter in multiplets, (ii) self-interacting dark radiation, and (iii) dark matter which is weakly coupled to dark radiation. We find that (i) dark matter cross sections are modified by multiplicity factors which have significant consequences for collider searches and indirect detection, and (ii) dark gluons have thermal abundances which affect the cosmic microwave background (CMB) as dark radiation. Unlike additional massless neutrino species the dark gluons are interacting and have vanishing viscosity and (iii) the coupling of dark radiation to dark matter represents a new mechanism for damping the large scale structure power spectrum. A combination of additional radiation and slightly damped structure is interesting because it can remove tensions between global Λ CDM fits from the CMB and direct measurements of the Hubble expansion rate (H0) and large scale structure (σ8).
Holographic duality from random tensor networks
NASA Astrophysics Data System (ADS)
Hayden, Patrick; Nezami, Sepehr; Qi, Xiao-Liang; Thomas, Nathaniel; Walter, Michael; Yang, Zhao
2016-11-01
Tensor networks provide a natural framework for exploring holographic duality because they obey entanglement area laws. They have been used to construct explicit toy models realizing many of the interesting structural features of the AdS/CFT correspondence, including the non-uniqueness of bulk operator reconstruction in the boundary theory. In this article, we explore the holographic properties of networks of random tensors. We find that our models naturally incorporate many features that are analogous to those of the AdS/CFT correspondence. When the bond dimension of the tensors is large, we show that the entanglement entropy of all boundary regions, whether connected or not, obey the Ryu-Takayanagi entropy formula, a fact closely related to known properties of the multipartite entanglement of assistance. We also discuss the behavior of Rényi entropies in our models and contrast it with AdS/CFT. Moreover, we find that each boundary region faithfully encodes the physics of the entire bulk entanglement wedge, i.e., the bulk region enclosed by the boundary region and the minimal surface. Our method is to interpret the average over random tensors as the partition function of a classical ferromagnetic Ising model, so that the minimal surfaces of Ryu-Takayanagi appear as domain walls. Upon including the analog of a bulk field, we find that our model reproduces the expected corrections to the Ryu-Takayanagi formula: the bulk minimal surface is displaced and the entropy is augmented by the entanglement of the bulk field. Increasing the entanglement of the bulk field ultimately changes the minimal surface behavior topologically, in a way similar to the effect of creating a black hole. Extrapolating bulk correlation functions to the boundary permits the calculation of the scaling dimensions of boundary operators, which exhibit a large gap between a small number of low-dimension operators and the rest. While we are primarily motivated by the AdS/CFT duality, the main
Davoudiasl, Hooman; Hooper, Dan; McDermott, Samuel D
2016-01-22
We describe a general scenario, dubbed "inflatable dark matter," in which the density of dark matter particles can be reduced through a short period of late-time inflation in the early Universe. The overproduction of dark matter that is predicted within many, otherwise, well-motivated models of new physics can be elegantly remedied within this context. Thermal relics that would, otherwise, be disfavored can easily be accommodated within this class of scenarios, including dark matter candidates that are very heavy or very light. Furthermore, the nonthermal abundance of grand unified theory or Planck scale axions can be brought to acceptable levels without invoking anthropic tuning of initial conditions. A period of late-time inflation could have occurred over a wide range of scales from ∼MeV to the weak scale or above, and could have been triggered by physics within a hidden sector, with small but not necessarily negligible couplings to the standard model.
NASA Astrophysics Data System (ADS)
Livio, Mario
2010-04-01
1. A brief history of dark matter Vera Rubin; 2. Microlensing towards the Magellanic Clouds Kailash Sahu; 3. Searching for galactic dark matter Harvey Richer; 4. Hot gas in clusters of galaxies and Omega Megan Donahue; 5. Tracking the Baryon density from the Big Bang to the present Gary Steigman; 6. Modified Newtonian dynamics and its implications Bob Sanders; 7. Cosmological parameters and quintessence from radio galaxies Ruth Daly and Eric Guerra; 8. The mass density of the Universe Neta Bahcall; 9. Growth of structure in the Universe John Peacock; 10. Cosmological implications of the most distant supernova (known) Adam Riess; 11. Dynamical probes of the Halo mass function Chris Kochanek; 12. Detection of gravitational waves from inflation Marc Kamionkowski and Andrew Jaffe; 13. Cosmological constant problems and their solution Alex Vilenkin; 14. Dark Matter and dark energy: a physicist's perspective Michael Dine.
Furukawa, Tomonori; Yokoyama, Shuichiro; Ichiki, Kiyotomo; Sugiyama, Naoshi; Mukohyama, Shinji E-mail: shu@a.phys.nagoya-u.ac.jp E-mail: naoshi@a.phys.nagoya-u.ac.jp
2010-05-01
We revisit ghost dark matter, the possibility that ghost condensation may serve as an alternative to dark matter. In particular, we investigate the Friedmann-Robertson-Walker (FRW) background evolution and the large-scale structure (LSS) in the ΛGDM universe, i.e. a late-time universe dominated by a cosmological constant and ghost dark matter. The FRW background of the ΛGDM universe is indistinguishable from that of the standard ΛCDM universe if M∼>1eV, where M is the scale of spontaneous Lorentz breaking. From the LSS we find a stronger bound: M∼>10eV. For smaller M, ghost dark matter would have non-negligible sound speed after the matter-radiation equality, and thus the matter power spectrum would significantly differ from observation. These bounds are compatible with the phenomenological upper bound M∼<100GeV known in the literature.
Nair, Remya; Jhingan, Sanjay E-mail: sanjay.jhingan@gmail.com
2013-02-01
We look for evidence for the evolution in dark energy density by employing Principal Component Analysis (PCA). Distance redshift data from supernovae and baryon acoustic oscillations (BAO) along with WMAP7 distance priors are used to put constraints on curvature parameter Ω{sub k} and dark energy parameters. The data sets are consistent with a flat Universe. The constraints on the dark energy evolution parameters obtained from supernovae (including CMB distance priors) are consistent with a flat ΛCDM Universe. On the other hand, in the parameter estimates obtained from the addition of BAO data the second principal component, which characterize a non-constant contribution from dark energy, is non-zero at 1σ. This could be a systematic effect and future BAO data holds key to making more robust claims.
NASA Astrophysics Data System (ADS)
Davoudiasl, Hooman; Hooper, Dan; McDermott, Samuel D.
2016-01-01
We describe a general scenario, dubbed "inflatable dark matter," in which the density of dark matter particles can be reduced through a short period of late-time inflation in the early Universe. The overproduction of dark matter that is predicted within many, otherwise, well-motivated models of new physics can be elegantly remedied within this context. Thermal relics that would, otherwise, be disfavored can easily be accommodated within this class of scenarios, including dark matter candidates that are very heavy or very light. Furthermore, the nonthermal abundance of grand unified theory or Planck scale axions can be brought to acceptable levels without invoking anthropic tuning of initial conditions. A period of late-time inflation could have occurred over a wide range of scales from ˜MeV to the weak scale or above, and could have been triggered by physics within a hidden sector, with small but not necessarily negligible couplings to the standard model.
NASA Technical Reports Server (NTRS)
Ebbeni, Jean (Editor)
1986-01-01
Papers are presented on a holographic recording material containing poly-n-vinylcarbozole, photoelectrochemical etching of holographic gratings in semiconductors, the analysis and construction of powered reflection holographic optical elements, achromatic display holograms in dichromated gelatin, and image blurring in display holograms and in holographic optical elements. Topics discussed include two-dimensional optical beam switching techniques using dynamnic holography, a new holographic interferometer with monomode fibers for integrated optics applications, computer controlled holography, and the copying of holograms using incoherent light. Consideration is given to holography of very far objects, rainbow holography with a multimode laser source, and the use of an endoscope for optical fiber holography.