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1

Investigation of the photon-number statistics of twin beams by direct detection.  

PubMed

We present the results of an experiment in which we observed photon-number statistics of twin beams emerging from a nondegenerate optical parametric oscillator. We generated the photocurrent for recording by detecting the light and mixing it with a standard electrical oscillator. The measured photocurrent variances exhibited a quantum correlation of as much as -4.9 dB between signal and idler, whereas their photon number distributions were super-Poissonian. We also obtained the difference photon-number distribution. PMID:18026416

Zhang, Yun; Kasai, Katsuyuki; Watanabe, Masayoshi

2002-07-15

2

Photon-number statistics from the phase-averaged quadrature-field distribution: Theory and ultrafast measurement  

NASA Astrophysics Data System (ADS)

We prove that the photon-number distribution of an arbitrary single-mode optical state can be calculated directly from the phase-averaged quadrature amplitude distribution, measured using optical homodyne detection. We experimentally demonstrate the application of this result by measuring the ultrafast (subpicosecond), time-resolved photon-number statistics of a weak field from a pulsed diode laser. Also presented is a numerical calculation of the photon-number distribution of a quadrature-squeezed vacuum state.

Munroe, M.; Boggavarapu, D.; Anderson, M. E.; Raymer, M. G.

1995-08-01

3

Photon-number-resolved detection of photon-subtracted thermal light.  

PubMed

We examine the photon statistics of photon-subtracted thermal light using photon-number-resolved detection. We demonstrate experimentally that the photon number distribution transforms from a Bose-Einstein distribution to a Poisson distribution as the number of subtracted photons increases. We also show that second- and higher-order photon correlation functions can be directly determined from the photon-number-resolved detection measurements of a single optical beam. PMID:23811867

Zhai, Yanhua; Becerra, Francisco E; Glebov, Boris L; Wen, Jianming; Lita, Adriana E; Calkins, Brice; Gerrits, Thomas; Fan, Jingyun; Nam, Sae Woo; Migdall, Alan

2013-07-01

4

Photon statistics in the polarization CEL  

NASA Astrophysics Data System (ADS)

In this work we find the photon statistics for the polarization CEL. The master equation, which couples diagonal and off diagonal matrix elements due to the initial atomic coherence, is solved by using the well known Scully-Lamb ansatz. The possible solutions and stability of the steady state photon number are investigated. Typical bistability behavior is found for a small range of the atomic coherence parameter.

Orszag, M.; Retamal, J. C.

1991-07-01

5

Two-bit quantum random number generator based on photon-number-resolving detection  

NASA Astrophysics Data System (ADS)

Here we present a new fast two-bit quantum random number generator based on the intrinsic randomness of the quantum physical phenomenon of photon statistics of coherent light source. Two-bit random numbers were generated according to the number of detected photons in each light pulse by a photon-number-resolving detector. Poissonian photon statistics of the coherent light source guaranteed the complete randomness of the bit sequences. Multi-bit true random numbers were generated for the first time based on the multi-photon events from a coherent light source.

Jian, Yi; Ren, Min; Wu, E.; Wu, Guang; Zeng, Heping

2011-07-01

6

Photon Counts Statistics in Leukocyte Cell Dynamics  

NASA Astrophysics Data System (ADS)

In the present experiment ultra-weak photon emission/ chemiluminescence from isolated neutrophils was recorded. It is associated with the production of reactive oxygen species (ROS) in the "respiratory burst" process which can be activated by PMA (Phorbol 12-Myristate 13-Acetate). Commonly, the reaction is demonstrated utilizing the enhancer luminol. However, with the use of highly sensitive photomultiplier equipment it is also recorded without enhancer. In that case, it can be hypothesized that photon count statistics may assist in understanding the underlying metabolic activity and cooperation of these cells. To study this hypothesis leukocytes were stimulated with PMA and increased photon signals were recorded in the quasi stable period utilizing Fano factor analysis at different window sizes. The Fano factor is defined by the variance over the mean of the number of photon within the observation time. The analysis demonstrated that the Fano factor of true signal and not of the surrogate signals obtained by random shuffling increases when the window size increased. It is concluded that photon count statistics, in particular Fano factor analysis, provides information regarding leukocyte interactions. It opens the perspective to utilize this analytical procedure in (in vivo) inflammation research. However, this needs further validation.

van Wijk, Eduard; van der Greef, Jan; van Wijk, Roeland

2011-12-01

7

Lasers, photon statistics, photon-correlation spectroscopy and subsequent applications  

NASA Astrophysics Data System (ADS)

A review is given of developments in the theory and application of the quantum statistics of visible-light photons, particularly of scattered laser light, over the fifty years since Maiman's publication of the first working laser. Some introductory pre-laser historical background to photon statistics is included and details are given of research and commercial developments in the field conducted in the author's laboratory in the UK over the period. The resulting emergence of photon statistics and photon-correlation spectroscopy as widely used techniques for non-invasive measurements of diffusion and velocity in many present-day areas of science and industry is described.

Pike, E. R.

2010-09-01

8

Relativistic statistical thermodynamics of dense photon gas  

NASA Astrophysics Data System (ADS)

We discuss some aspects of interactions of high-frequency electromagnetic waves with plasmas, assuming that the intensity of radiation is sufficiently large, so that the photon-photon interaction is more likely than the photon-plasma particle interaction. In the stationary limit, solving the kinetic equation of the photon gas, we derive a distribution function. With this distribution function at hand, we investigate the adiabatic photon self-capture and obtain the number density of the trapped photons. We employ the distribution function to calculate the thermodynamic quantities for the photon gas. Having expressions of the entropy and the pressure of the photon gas, we define the heat capacities and exhibit the existence of the ratio of the specific heats ? , which equals 7/6 for nonrelativistic temperatures. In addition, we disclose the magnitude of the mean square fluctuation of the number of photons. Finally, we discuss the uniform expansion of the photon gas.

Tsintsadze, Levan N.; Kishimoto, Yasuaki; Callebaut, Dirk K.; Tsintsadze, Nodar L.

2007-07-01

9

Relativistic statistical thermodynamics of dense photon gas  

SciTech Connect

We discuss some aspects of interactions of high-frequency electromagnetic waves with plasmas, assuming that the intensity of radiation is sufficiently large, so that the photon-photon interaction is more likely than the photon-plasma particle interaction. In the stationary limit, solving the kinetic equation of the photon gas, we derive a distribution function. With this distribution function at hand, we investigate the adiabatic photon self-capture and obtain the number density of the trapped photons. We employ the distribution function to calculate the thermodynamic quantities for the photon gas. Having expressions of the entropy and the pressure of the photon gas, we define the heat capacities and exhibit the existence of the ratio of the specific heats {gamma}, which equals 7/6 for nonrelativistic temperatures. In addition, we disclose the magnitude of the mean square fluctuation of the number of photons. Finally, we discuss the uniform expansion of the photon gas.

Tsintsadze, Levan N.; Kishimoto, Yasuaki; Callebaut, Dirk K.; Tsintsadze, Nodar L. [Department of Fundamental Energy, Graduate School of Energy Science, Kyoto University (Japan); Physics Department, University of Antwerp, Antwerpen (Belgium); Department of Plasma Physics, Tbilisi State University, Tbilisi (Georgia)

2007-07-15

10

Photon statistics: math versus mysticism  

NASA Astrophysics Data System (ADS)

Critical analysis is given for mystical aspects of the current understanding of interaction between charged particles: wave-particle duality and nonlocal entanglement. A possible statistical effect concerning distribution functions for coincidences between the output channels of beam splitters is described. If this effect is observed in beam splitter data, ten significant evidence for photon splitting, i.e. , against the notion that light is ultimately packaged in finite chunks, has been found. An argument is given for the invalidity of the meaning attached to tests of Bell inequalities. Additionally, a totally classical paradigm for the calculation of the customary expression for the "quantum" coincidence coefficient pertaining to the singlet state is described. If fully accounts for the results of experimental tests of Bell inequalities taken nowadays to prove the reality of entanglement and non-locality in quantum phenomena of, inter alia, light. Described. It fully accounts for the results of experimental tests of Bell inequalities take n nowadays to prove the reality of entanglement and non-locality in quantum phenomena of inter alia, light.

Kracklauer, A. F.

2013-10-01

11

Probing higher order correlations of the photon field with photon number resolving avalanche photodiodes.  

PubMed

We demonstrate the use of two high speed avalanche photodiodes in exploring higher order photon correlations. By employing the photon number resolving capability of the photodiodes the response to higher order photon coincidences can be measured. As an example we show experimentally the sensitivity to higher order correlations for three types of photon sources with distinct photon statistics. This higher order correlation technique could be used as a low cost and compact tool for quantifying the degree of correlation of photon sources employed in quantum information science. PMID:21747481

Dynes, J F; Yuan, Z L; Sharpe, A W; Thomas, O; Shields, A J

2011-07-01

12

Statistics: It's in the Numbers!  

ERIC Educational Resources Information Center

Mathematics and statistics play important roles in peoples' lives today. A day hardly passes that they are not bombarded with many different kinds of statistics. As consumers they see statistical information as they surf the web, watch television, listen to their satellite radios, or even read the nutrition facts panel on a cereal box in the…

Deal, Mary M.; Deal, Walter F., III

2007-01-01

13

Axion–photon coupling in the limit of photon statistics  

NASA Astrophysics Data System (ADS)

It has been shown that interactions between photons and exotic fields, e.g. axions and axion like particles, may result in periodic splitting known as bifurcation. Some of the measurable effects have been simulated and reported in previous papers, including the central depletion of photons due to splitting and the shifting of the beam energy due to higher order terms. This paper takes a look at what happens when the limit of photon statistics is reached. Similar to how shot noise arises, additional chaotic movement of the beam center occurs due to the quantum nature of light and axion–photon coupling. Most significantly, the movement scales as first order with the axion–photon coupling constant.

Scarlett, Carol

2014-06-01

14

Observing fermionic statistics with photons in arbitrary processes  

PubMed Central

Quantum mechanics defines two classes of particles-bosons and fermions-whose exchange statistics fundamentally dictate quantum dynamics. Here we develop a scheme that uses entanglement to directly observe the correlated detection statistics of any number of fermions in any physical process. This approach relies on sending each of the entangled particles through identical copies of the process and by controlling a single phase parameter in the entangled state, the correlated detection statistics can be continuously tuned between bosonic and fermionic statistics. We implement this scheme via two entangled photons shared across the polarisation modes of a single photonic chip to directly mimic the fermion, boson and intermediate behaviour of two-particles undergoing a continuous time quantum walk. The ability to simulate fermions with photons is likely to have applications for verifying boson scattering and for observing particle correlations in analogue simulation using any physical platform that can prepare the entangled state prescribed here.

Matthews, Jonathan C. F.; Poulios, Konstantinos; Meinecke, Jasmin D. A.; Politi, Alberto; Peruzzo, Alberto; Ismail, Nur; Worhoff, Kerstin; Thompson, Mark G.; O'Brien, Jeremy L.

2013-01-01

15

Statistical Treatment of Nominal Numbers.  

National Technical Information Service (NTIS)

An attempt is made to find an answer to Lord's parable of the football numbers by demonstrating that he ignored the well known principle that a measurement operation should be consistent over allowable transformations of scale. An example is given to demo...

D. R. Harris

1971-01-01

16

Resolving photon number states in a superconducting circuit.  

PubMed

Electromagnetic signals are always composed of photons, although in the circuit domain those signals are carried as voltages and currents on wires, and the discreteness of the photon's energy is usually not evident. However, by coupling a superconducting quantum bit (qubit) to signals on a microwave transmission line, it is possible to construct an integrated circuit in which the presence or absence of even a single photon can have a dramatic effect. Such a system can be described by circuit quantum electrodynamics (QED)-the circuit equivalent of cavity QED, where photons interact with atoms or quantum dots. Previously, circuit QED devices were shown to reach the resonant strong coupling regime, where a single qubit could absorb and re-emit a single photon many times. Here we report a circuit QED experiment in the strong dispersive limit, a new regime where a single photon has a large effect on the qubit without ever being absorbed. The hallmark of this strong dispersive regime is that the qubit transition energy can be resolved into a separate spectral line for each photon number state of the microwave field. The strength of each line is a measure of the probability of finding the corresponding photon number in the cavity. This effect is used to distinguish between coherent and thermal fields, and could be used to create a photon statistics analyser. As no photons are absorbed by this process, it should be possible to generate non-classical states of light by measurement and perform qubit-photon conditional logic, the basis of a logic bus for a quantum computer. PMID:17268464

Schuster, D I; Houck, A A; Schreier, J A; Wallraff, A; Gambetta, J M; Blais, A; Frunzio, L; Majer, J; Johnson, B; Devoret, M H; Girvin, S M; Schoelkopf, R J

2007-02-01

17

On Statistical Testing of Random Numbers Generators  

Microsoft Academic Search

Maurer's test is nowadays a basic statistical tool for testing physical random number gen- erators in cryptographic applications. Based on a statistical analysis of this test we propose simple and efiective methods for its improvement. These methods are related to the m - spacing technique common in goodness-of-flt problems and the L - leave out method used for a noise

Fida El Haje; Yuri Golubev; Pierre-yvan Liardet; Yannick Teglia

2006-01-01

18

Ideal photon number amplifier and duplicator  

NASA Technical Reports Server (NTRS)

The photon number-amplification and number-duplication mechanism are analyzed in the ideal case. The search for unitary evolutions leads to consider also a number-deamplification mechanism, the symmetry between amplification and deamplification being broken by the integer-value nature of the number operator. Both transformations, amplification and duplication, need an auxiliary field which, in the case of amplification, turns out to be amplified in the inverse way. Input-output energy conservation is accounted for using a classical pump or through frequency-conversion of the fields. Ignoring one of the fields is equivalent to considering the amplifier as an open system involving entropy production. The Hamiltonians of the ideal devices are given and compared with those of realistic systems.

Dariano, G. M.

1992-01-01

19

Interaction of Fixed Number of Photons with Retinal Rod Cells  

NASA Astrophysics Data System (ADS)

New tools and approaches of quantum optics offer a unique opportunity to generate light pulses carrying a precise number of photons. Accurate control over the light pulses helps to improve the characterization of photoinduced processes. Here, we study interaction of a specialized light source which provides flashes containing just one photon, with retinal rod cells of Xenopus laevis toads. We provide unambiguous proof of the single-photon sensitivity of rod cells without relying on the statistical modeling. We determine their quantum efficiencies without the use of any precalibrated detectors and obtain the value of (29±4.7)%. Our approach provides the path for future studies and applications of quantum properties of light in phototransduction, vision, and photosynthesis.

Phan, Nam Mai; Cheng, Mei Fun; Bessarab, Dmitri A.; Krivitsky, Leonid A.

2014-05-01

20

Calibration of single-photon detectors using quantum statistics  

SciTech Connect

I show that calibration of the single-photon detector can be performed without knowledge of the signal parameters. Only partial information about the state statistics is sufficient for that. If one knows that the state is the squeezed one or the squeezed one mixed with the incoherent radiation, one can infer both the parameters of the state and the efficiency of the detector. For that one needs only to measure on/off statistics of detector clicks for the number of known absorbers placed before the detector. Thus, I suggest a scheme that performs a tomography of the signal and the measuring apparatus simultaneously.

Mogilevtsev, D. [Institute of Physics, Belarus National Academy of Sciences, F.Skarina Ave. 68, Minsk 220072 (Belarus) and Instituto de Fisica, UNICAMP, CP 6165, Campinas-SP, 13083-970 (Brazil)

2010-08-15

21

Statistical fitting accuracy in photon correlation spectroscopy  

NASA Technical Reports Server (NTRS)

Continuing our experimental investigation of the fitting accuracy associated with photon correlation spectroscopy, we collect 150 correlograms of light scattered at 90 deg from a thermostated sample of 91-nm-diameter, polystyrene latex spheres in water. The correlograms are taken with two correlators: one with linearly spaced channels and one with geometrically spaced channels. Decay rates are extracted from the single-exponential correlograms with both nonlinear least-squares fits and second-order cumulant fits. We make several statistical comparisons between the two fitting techniques and verify an earlier result that there is no sample-time dependence in the decay rate errors. We find, however, that the two fitting techniques give decay rates that differ by 1 percent.

Shaumeyer, J. N.; Briggs, Matthew E.; Gammon, Robert W.

1993-01-01

22

Statistical fitting accuracy in photon correlation spectroscopy.  

PubMed

Continuing our experimental investigation of the fitting accuracy associated with photon correlation spectroscopy, we collect 150 correlograms of light scattered at 90° from a thermostated sample of 91-nm-diameter, polystyrene latex spheres in water. The correlograms are taken with two correlators: one with linearly spaced channels and one with geometrically spaced channels. Decay rates are extracted from the single-exponential correlograms with both nonlinear, least-squares fits and second-order cumulant fits. We make several statistical comparisons between the two fitting techniques and verify an earlier result that there is no sample-time dependence in the decay rate errors. We find, however, that the two fitting techniques give decay rates that differ by 1%. PMID:20830019

Shaumeyer, J N; Briggs, M E; Gammon, R W

1993-07-20

23

Joint photon and wave statistics in nonlinear optical couplers  

NASA Astrophysics Data System (ADS)

Nonlinear optical couplers based on optical parametric processes and Raman-Brillouin scattering are discussed from the point of view of their nonclassical behaviour using joint photon-number and integrated-intensity probability distributions and derived quantum statistical quantities. Employing these tools quantum entanglement of modes and their nonclassical properties are demonstrated by means of conditional probability distributions and their Fano factors, difference-number probability distributions, quantum oscillations, squeezing of vacuum fluctuations and negative values of the joint wave probability quasidistributions in time evolution. Sub-Poissonian and sub-shot-noise properties are determined for initial coherent, chaotic and squeezed light.

Pe?ina, Jan; K?epelka, Jaromír

2014-09-01

24

Nonlinearity sensing via photon-statistics excitation spectroscopy  

SciTech Connect

We propose photon-statistics excitation spectroscopy as an adequate tool to describe the optical response of a nonlinear system. To this end we suggest to use optical excitation with varying photon statistics as another spectroscopic degree of freedom to gather information about the system in question. The responses of several simple model systems to excitation beams with different photon statistics are discussed. Possible spectroscopic applications in terms of identifying lasing operation are pointed out.

Assmann, Marc; Bayer, Manfred [Experimentelle Physik 2, Technische Universitaet Dortmund, D-44221 Dortmund (Germany)

2011-11-15

25

Inverse problems in statistical mechanics and photonics  

NASA Astrophysics Data System (ADS)

In an inverse problem, one seeks the nature of the components of a system with known (or targeted) resultant behavior---perhaps opposite to the traditional trajectory of problem solving in physical research. In this thesis, a number of inverse problems in two categories are considered. In the first, in many-body classical systems with isotropic two-body interactions, we target uncharacteristic, technologically relevant thermodynamic behavior. In the second, we consider two problems in electromagnetic scattering and photonics. Increasingly, experimentalists have been able to tailor isotropic interactions between micron-scale colloidal spheres, allowing for the possibility of targeted self-assembly of a desired crystal structure upon freezing. Self-assembly of certain structures, the diamond lattice in particular, has a great deal of technological potential in the fields of optoelectronics and photonics. We present here new computational algorithms that find isotropic interaction potentials that yield targeted ground state crystal structures. These algorithms are applied to find interaction potentials for the honeycomb lattice (which is the two-dimensional analog of diamond), the square lattice, the simple cubic lattice, the wurtzite as well as the diamond lattice. We also present an isotropic interaction potential that gives rise to negative thermal expansion, a macroscopic behavior that has previously been associated with a highly anisotropic microscopic mechanism. Furthermore, we show that systems with only isotropic interactions may exhibit a negative Poisson's ratio, as long as they are under tension. We derive linear constraints involving the derivatives of the pair potential that gives rise to this behavior. In a study of electromagnetic scattering in random dielectric two-component composites, we use a strong-contrast perturbation expansion to obtain analytic expressions for the effective dielectric tensor to arbitrary order in the dielectric contrast between component phases. In the process, we show that attenuation due to elastic scattering in a lossless dielectric medium in the long-wavelength regime is closely related to the coarseness of the composite. In the final inverse problem, we find quasiperiodic dielectric patterns that have maximal photonic bandgaps, for a number of different crystallographically forbidden rotational symmetries. The structures have the largest known gaps for quasicrystals in two dimensions, and were derived using a novel optimization routine that we present here. Quasicrystals are ideal structures for producing full photonic bandgaps since their high rotational symmetries give rise to a more isotropic band structure.

Rechtsman, Mikael C.

26

Optical Parametric Amplification of Single Photon: Statistical Properties and Quantum Interference  

NASA Astrophysics Data System (ADS)

By using phase space method, we theoretically investigate the quantum statistical properties and quantum interference of optical parametric amplification of single photon. The statistical properties, such as the Wigner function (WF), average photon number, photon number distribution and parity, are derived analytically for the fields of the two output ports. The results indicate that the fields in the output ports are multiphoton states rather than single photon state due to the amplification of the optical parametric amplifiers (OPA). In addition, the phase sensitivity is also examined by using the detection scheme of parity measurement.

Xu, Xue-Xiang; Yuan, Hong-Chun

2014-05-01

27

Photon number squeezed states in semiconductor lasers  

NASA Technical Reports Server (NTRS)

Electromagnetic fields, with the noise on one quadrature component reduced to below the quantum mechanical zero-point fluctuation level and the noise on the other quadrature component enhanced to above it, are currently of great interest in quantum optics because of their potential applications to various precision measurements. Such squeezed states of light are usually produced by imposing nonlinear unitary evolution on coherent (or vacuum) states. On the other hand, squeezed states with reduced photon number noise and enhanced phase noise are generated directly by a constant current-driven semiconductor laser. This is the simplest scheme for the generation of nonclassical light, and so far it has yielded the largest quantum noise reduction. The mutual coupling between a lasing junction and an external electrical circuit provides opportunities for exploring the macroscopic and microscopic quantum effects in open systems.

Yamamoto, Yoshihisa; Machida, Susumu; Richardson, Wayne H.

1992-01-01

28

Relativistic statistical thermodynamics of dense photon gas  

Microsoft Academic Search

We discuss some aspects of interactions of high-frequency electromagnetic waves with plasmas, assuming that the intensity of radiation is sufficiently large, so that the photon-photon interaction is more likely than the photon-plasma particle interaction. In the stationary limit, solving the kinetic equation of the photon gas, we derive a distribution function. With this distribution function at hand, we investigate the

Levan N. Tsintsadze; Yasuaki Kishimoto; Dirk K. Callebaut; Nodar L. Tsintsadze

2007-01-01

29

Statistical Analysis of Random Number Generators  

NASA Astrophysics Data System (ADS)

In many applications, for example cryptography and Monte Carlo simulation, there is need for random numbers. Any procedure, algorithm or device which is intended to produce such is called a random number generator (RNG). What makes a good RNG? This paper gives an overview on empirical testing of the statistical properties of the sequences produced by RNGs and special software packages designed for that purpose. We also present the results of applying a particular test suite--TestU01-- to a family of RNGs currently being developed at the Centro Interdipartimentale Vito Volterra (CIVV), Roma, Italy.

Accardi, Luigi; Gäbler, Markus

2011-01-01

30

Laser ranging at few-photon level by photon-number-resolving detection.  

PubMed

Sensitive laser ranging was demonstrated at few-photon level using photon-number-resolving (PNR) detectors. The reflected photon pulses from a non-cooperation remote target were distinguished in a sunlight environment of 2.5×103??lx by setting the discrimination threshold at 5-photon level. By comparing the detected photon numbers, two remote targets with different reflection coefficients were well recognized. PNR detection facilitated remote laser ranging of few-photon sensitivity with similar capabilities of linear optical detectors. This technique avoids photon-counting saturation and is important for ultra-long distance LIDAR and 3D imaging at a few photon level. PMID:24979422

Bao, Zeyu; Liang, Yan; Wang, Zhiyuan; Li, Zhaohui; Wu, E; Wu, Guang; Zeng, Heping

2014-06-20

31

Photon-number discriminating superconducting transition-edge sensors  

Microsoft Academic Search

Photon-number discriminating detectors are fundamental to new quantum photon-based standards. We report results on superconducting transition-edge sensors based on Ti\\/Au and Ti\\/Pd bilayers allowing pulses containing up to five photons to be discriminated.

Mauro Rajteri; Emanuele Taralli; Chiara Portesi; Eugenio Monticone; Jörn Beyer

2009-01-01

32

Pump statistics and field squeezing in a generalized many cascade two-photon CEL  

NASA Astrophysics Data System (ADS)

I show that the squeezing and the brightness of the squeezed light of a many cascade two-photon CEL will have a substantial increase if the upper and the middle levels of the active atom become q- and ( k+ 1)-fold almost degenerate, respectively. besides the lower levels. The pump statistics only affects the photon-number noise of a resonant many cascade two-photon CEL operated in the linear region.

Huang, Hong-Bin

1994-11-01

33

Testing photons' Bose-Einstein statistics with Compton scattering  

SciTech Connect

It is an empirical question whether photons always obey Bose-Einstein statistics, but devising and interpreting experimental tests of photon statistics can be a challenge. The nonrelativistic cross section for Compton scattering illustrates how a small admixture {nu} of wrong-sign statistics leads to a loss of gauge invariance; there is a large anomalous amplitude for scattering timelike photons. Nevertheless, one can interpret the observed transparency of the solar wind plasma at low frequencies as a bound {nu}<10{sup -25} if Lorentz symmetry is required. If there is instead a universal preferred frame, the bound is {nu}<10{sup -14}, still strong compared with previous results.

Altschul, Brett [Department of Physics and Astronomy, University of South Carolina, Columbia, South Carolina 29208 (United States)

2010-11-15

34

Photon number-resolved detectors: prospects and applications  

Microsoft Academic Search

The Photon Number-Resolved (PNR) detectors are capable to distinguish between finite numbers n of photons (n = 1, 2, 3, ...) within an ultrafast (femtosecond or picosecond range) week radiation pulse. Recently, a great interest to such devices has been expressed by the quantum information sciences. In the nearest future, an interest to development of such devices can be significantly

Aleksandr Verevkin

2007-01-01

35

Towards a Metric to Estimate Atomic Number from Backscattered Photons  

SciTech Connect

An ability to determine the atomic number of a material in a cargo container would be helpful in interdicting smuggled nuclear materials. This paper examines two processes by which high energy photons interact with matter; Compton scattering and pair production. The ratio of the number of photons which originate from the annihilation of positrons resulting from pair production and the number of photons coming from Compton scattering gives a good indication of atomic number. At large angles relative to an incident beam - i.e. backscattered, there is good separation in energy between Compton scattered photons and photons from positron annihilations. This ratio can then be cleanly determined in order to estimate atomic number.

Walston, S; Dietrich, D; Wurtz, R

2009-08-17

36

Waveguide photon-number-resolving detectors for quantum photonic integrated circuits  

NASA Astrophysics Data System (ADS)

Quantum photonic integration circuits are a promising approach to scalable quantum processing with photons. Waveguide single-photon-detectors (WSPDs) based on superconducting nanowires have been recently shown to be compatible with single-photon sources for a monolithic integration. While standard WSPDs offer single-photon sensitivity, more complex superconducting nanowire structures can be configured to have photon-number-resolving capability. In this work, we present waveguide photon-number-resolving detectors (WPNRDs) on GaAs/Al0.75Ga0.25As ridge waveguides based on a series connection of nanowires. The detection of 0-4 photons has been demonstrated with a four-wire WPNRD, having a single electrical read-out. A device quantum efficiency of ~24% is reported at 1310 nm for the transverse electric polarization.

Sahin, D.; Gaggero, A.; Zhou, Z.; Jahanmirinejad, S.; Mattioli, F.; Leoni, R.; Beetz, J.; Lermer, M.; Kamp, M.; Höfling, S.; Fiore, A.

2013-09-01

37

Asymptotic statistical analysis of pseudo random numbers  

Microsoft Academic Search

edu Abstract-Computer simulation is a widely used powerful tool for solving real world problems. Pseudo random number plays an important role in computer simulation and modeling. It acts like the real random number. We discuss the asymptotic properties of pseudo random numbers as the period size of a random number generator approaches to infinity . Our results show that the

Alexandra L. Wang; Zhiguang Xu; Charles J. Kicey

2011-01-01

38

Generalized photon-added coherent state and its quantum statistical properties  

NASA Astrophysics Data System (ADS)

In this paper, we propose a class of the generalized photon-added coherent states (GPACSs) obtained by repeatedly operating the combination of Bosonic creation and annihilation operatoes on the coherent state. The normalization factor of GPACS is related to Hermite polynomial. We also derive the explicit expressions of its statistical properties such as photocount distribution, Wigner function and tomogram and investigate their behaviour as the photon-added number varies graphically. It is found that GPACS is a kind of nonclassical state since Wigner function exhibits the negativity by increasing the photon-added number.

Yuan, Hong-Chun; Xu, Xue-Xiang; Fan, Hong-Yi

2010-10-01

39

High intrinsic energy resolution photon number resolving detectors  

NASA Astrophysics Data System (ADS)

Transition Edge Sensors (TESs) are characterized by the intrinsic figures of merit to resolve both the energy and the statistical distribution of the incident photons. These properties lead TES devices to become the best single photon detectors for quantum technology experiments. For a TES based on titanium and gold, has been reached, at telecommunication wavelength, an unprecedented intrinsic energy resolution (0.113 eV). The uncertainty analysis of both energy resolution and photon state assignment has been discussed. The thermal properties of the superconductive device have been studied by fitting the bias curves to evaluate the theoretical limit of the energy resolution.

Lolli, L.; Taralli, E.; Portesi, C.; Monticone, E.; Rajteri, M.

2013-07-01

40

Quantum channel using photon number correlated twin beams.  

PubMed

We report quantum communications channel using photon number correlated twin beams. The twin beams are generated from a nondegenerate optical parametric oscillator, and the photon number difference is used to encode the signal. The bit error rate of our system will be 0.067 by using the twin beams comparing with 0.217 by using the coherent state as the signal carrier. PMID:19471495

Zhang, Yun; Kasai, Katsuyuki; Hayasaka, Kazuhiro

2003-12-29

41

Number Hunting: Statistics on the Net.  

ERIC Educational Resources Information Center

Discusses how to find statistical data on the Internet, particularly with awareness of lag times associated with posted data and of the large quantity of university sources. Lists World Wide Web sites under the headings of metasites, agriculture, banking, business, crime, economics, education, energy, government, health, international, local…

Raeder, Aggi

1996-01-01

42

Counting statistics of photons produced by electronic shot noise.  

PubMed

A theory is presented for the photodetection statistics of radiation produced by current fluctuations in a phase-coherent conductor. Deviations are found from the Poisson statistics that would result from a classical current. For detection in a narrow frequency interval delta omega, the photocount distribution has the negative-binomial form of blackbody radiation if e delta omega is less than the mean current I in the conductor. When electronic localization sets in, I drops below e delta omega and a different type of super-Poissonian photon statistics results. PMID:11177916

Beenakker, C W; Schomerus, H

2001-01-22

43

Apollo by the Numbers: A Statistical Reference  

NASA Technical Reports Server (NTRS)

The purpose of this work is to provide researchers, students, and space enthusiasts with a comprehensive reference for facts about Project Apollo, America's effort to put humans in the Moon. Research for this work started in 1988, when the author discovered that, despite the number of excellent books that focused on the drama of events that highlighted Apollo, there were none that focused on the drama of the numbers. This book is separated into two parts. The first part contains narratives for the Apollo 1 fire and the 11 flown Apollo missions. Included after each narrative is a series of data tables, followed by a comprehensive timeline of events from just before liftoff to just after crew and spacecraft recovery. The second part contains more than 50 tables. These tables organize much of the data from the narratives in one place so they can be compared among all missions. The tables offer additional data as well. The reader can select a specific mission narrative or specific data table by consulting the Table of Contents.

Orloff, Richard; Garber, Stephen (Technical Monitor)

2000-01-01

44

Ultrabroadband direct detection of nonclassical photon statistics at telecom wavelength.  

PubMed

Broadband light sources play essential roles in diverse fields, such as high-capacity optical communications, optical coherence tomography, optical spectroscopy, and spectrograph calibration. Although a nonclassical state from spontaneous parametric down-conversion may serve as a quantum counterpart, its detection and characterization have been a challenging task. Here we demonstrate the direct detection of photon numbers of an ultrabroadband (110 nm FWHM) squeezed state in the telecom band centred at 1535 nm wavelength, using a superconducting transition-edge sensor. The observed photon-number distributions violate Klyshko's criterion for the nonclassicality. From the observed photon-number distribution, we evaluate the second- and third-order correlation functions, and characterize a multimode structure, which implies that several tens of orthonormal modes of squeezing exist in the single optical pulse. Our results and techniques open up a new possibility to generate and characterize frequency-multiplexed nonclassical light sources for quantum info-communications technology. PMID:24694515

Wakui, Kentaro; Eto, Yujiro; Benichi, Hugo; Izumi, Shuro; Yanagida, Tetsufumi; Ema, Kazuhiro; Numata, Takayuki; Fukuda, Daiji; Takeoka, Masahiro; Sasaki, Masahide

2014-01-01

45

Ultrabroadband direct detection of nonclassical photon statistics at telecom wavelength  

NASA Astrophysics Data System (ADS)

Broadband light sources play essential roles in diverse fields, such as high-capacity optical communications, optical coherence tomography, optical spectroscopy, and spectrograph calibration. Although a nonclassical state from spontaneous parametric down-conversion may serve as a quantum counterpart, its detection and characterization have been a challenging task. Here we demonstrate the direct detection of photon numbers of an ultrabroadband (110 nm FWHM) squeezed state in the telecom band centred at 1535 nm wavelength, using a superconducting transition-edge sensor. The observed photon-number distributions violate Klyshko's criterion for the nonclassicality. From the observed photon-number distribution, we evaluate the second- and third-order correlation functions, and characterize a multimode structure, which implies that several tens of orthonormal modes of squeezing exist in the single optical pulse. Our results and techniques open up a new possibility to generate and characterize frequency-multiplexed nonclassical light sources for quantum info-communications technology.

Wakui, Kentaro; Eto, Yujiro; Benichi, Hugo; Izumi, Shuro; Yanagida, Tetsufumi; Ema, Kazuhiro; Numata, Takayuki; Fukuda, Daiji; Takeoka, Masahiro; Sasaki, Masahide

2014-04-01

46

Ultrabroadband direct detection of nonclassical photon statistics at telecom wavelength  

PubMed Central

Broadband light sources play essential roles in diverse fields, such as high-capacity optical communications, optical coherence tomography, optical spectroscopy, and spectrograph calibration. Although a nonclassical state from spontaneous parametric down-conversion may serve as a quantum counterpart, its detection and characterization have been a challenging task. Here we demonstrate the direct detection of photon numbers of an ultrabroadband (110?nm FWHM) squeezed state in the telecom band centred at 1535?nm wavelength, using a superconducting transition-edge sensor. The observed photon-number distributions violate Klyshko's criterion for the nonclassicality. From the observed photon-number distribution, we evaluate the second- and third-order correlation functions, and characterize a multimode structure, which implies that several tens of orthonormal modes of squeezing exist in the single optical pulse. Our results and techniques open up a new possibility to generate and characterize frequency-multiplexed nonclassical light sources for quantum info-communications technology.

Wakui, Kentaro; Eto, Yujiro; Benichi, Hugo; Izumi, Shuro; Yanagida, Tetsufumi; Ema, Kazuhiro; Numata, Takayuki; Fukuda, Daiji; Takeoka, Masahiro; Sasaki, Masahide

2014-01-01

47

Accessing photon bunching with a photon number resolving multi-pixel detector.  

PubMed

In quantum optics and its applications, there is an urgent demand for photon-number resolving detectors. Recently, there appeared multi-pixel counters (MPPC) that are able to distinguish between 1,2,..10 photons. At the same time, strong coupling between different pixels (crosstalk) hinders their photon-number resolution. In this work, we suggest a method for `filtering out' the crosstalk effect in the measurement of intensity correlation functions. The developed approach can be expanded to the analysis of higher-order intensity correlations by using just a single MPPC. PMID:21643191

Kalashnikov, Dmitry A; Tan, Si Hui; Chekhova, Maria V; Krivitsky, Leonid A

2011-05-01

48

Sum-frequency generation from photon number squeezed light  

NASA Technical Reports Server (NTRS)

We investigate the quantum fluctuations of the fields produced in sum-frequency (SF) generation from light initially in the photon number squeezed state. It is found that, to the fourth power term, the output SF light is sub-Poissonian whereas the quantum fluctuations of the input beams increase. Quantum anticorrelation also exists in SF generation.

Wu, Ling-An; Du, Cong-Shi; Wu, Mei-Juan; Li, Shi-Qun

1994-01-01

49

Photon number-resolved detectors: prospects and applications  

NASA Astrophysics Data System (ADS)

The Photon Number-Resolved (PNR) detectors are capable to distinguish between finite numbers n of photons (n = 1, 2, 3, ...) within an ultrafast (femtosecond or picosecond range) week radiation pulse. Recently, a great interest to such devices has been expressed by the quantum information sciences. In the nearest future, an interest to development of such devices can be significantly enhanced by emerging class of new nanophotonic and biological applications, such as single-molecule studies with fluorescent nanoparticles. As it was found recently, the multiexciton state achieved through fast pulse laser irradiation of individual nanoparticle lead to multiphoton character of light emission. The exact knowledge of the number of photons emitted by individual nanoparticle in colloids can provide us with deeper understanding of the interaction between single fluorescent nanoparticle and its environment. However, the development of PNR devices would be necessary to establish such novel photon number-resolved imaging technologies. In this article we briefly review some basic approaches to design and development of the future PNR detectors and electronic readouts.

Verevkin, Aleksandr

2007-02-01

50

Finite-key analysis of the six-state protocol with photon number resolution detectors  

NASA Astrophysics Data System (ADS)

The six-state protocol is a discrete-variable protocol for quantum key distribution, that permits to tolerate a noisier channel than the BB84 protocol. In this work we provide a lower bound on the maximum achievable key rate of a practical implementation of the entanglement-based version of the six-state protocol. Regarding the experimental set-up we consider that the source is untrusted and the photon-number statistics is measured using photon-number-resolving detectors. We provide the formula for the key rate for a finite initial number of resources. As an illustration of the considered formalism, we calculate the key rate for the setting where the source produces entangled photon pairs via parametric down-conversion and the losses in the channel depend on the distance. As a result we find that the finite-key corrections for the considered scenario are not negligible and they should be considered in any practical analysis.

Abruzzo, Silvestre; Mertz, Markus; Kampermann, Hermann; Bruss, Dagmar

2011-10-01

51

Effective atomic numbers for photon energy absorption and photon attenuation of tissues from human organs  

Microsoft Academic Search

Effective atomic numbers for photon energy- absorption (Zpeaeff) and photon interaction (Zpieff) of human organs and tissues such as cortical bone, ovary, eye lens, testis, breast tissue, adipose tissue, lung tissue, soft tissue, soft tissue, (4-component), blood (whole), brain (grey\\/white matter), and skeletal muscle have been calculated by a direct method in the energy region of 1 keV to 20

Shivaramu

2002-01-01

52

Statistical Evaluation of a Superconductive Physical Random Number Generator  

NASA Astrophysics Data System (ADS)

A physical random number generator, which generates truly random number trains by using the randomness of physical phenomena, is widely used in the field of cryptographic applications. We have developed an ultra high-speed superconductive physical random number generator that can generate random numbers at a frequency of more than 10GHz by utilizing the high-speed operation and high-sensitivity of superconductive integrated circuits. In this study, we have statistically evaluated the quality of the random number trains generated by the superconductive physical random number generator. The performances of the statistical tests were based on a test method provided by National Institute of Standards and Technology (NIST). These statistical tests comprised several fundamental tests that were performed to evaluate the random number trains for their utilization in practical cryptographic applications. We have generated 230 random number trains consisting of 20, 000-bits by using the superconductive physical random number generator fabricated by the SRL 2.5kA/cm2 Nb standard process. The generated random number trains passed all the fundamental statistical tests. This result indicates that the superconductive random number generator can be sufficiently utilized in practical applications.

Sugiura, Tatsuro; Yamanashi, Yuki; Yoshikawa, Nobuyuki

53

Statistical error in particle simulations of low mach number flows  

SciTech Connect

We present predictions for the statistical error due to finite sampling in the presence of thermal fluctuations in molecular simulation algorithms. The expressions are derived using equilibrium statistical mechanics. The results show that the number of samples needed to adequately resolve the flowfield scales as the inverse square of the Mach number. Agreement of the theory with direct Monte Carlo simulations shows that the use of equilibrium theory is justified.

Hadjiconstantinou, N G; Garcia, A L

2000-11-13

54

High quantum-efficiency photon-number-resolving detector for photonic on-chip information processing  

NASA Astrophysics Data System (ADS)

The integrated optical circuit is a promising architecture for the realization of complex quantum optical states and information networks. One element that is required for many of these applications is a high-efficiency photon detector capable of photon-number discrimination. We present an integrated photonic system in the telecom band at 1550 nm based on UV-written silica-on-silicon waveguides and modified transition-edge sensors capable of number resolution and over 40% efficiency. Exploiting the mode transmission failure of these devices, we multiplex three detectors in series to demonstrate a combined 79% +/- 2% detection efficiency with a single pass, and 88% +/- 3% at the operating wavelength of an on-chip terminal reflection grating. Furthermore, our optical measurements clearly demonstrate no significant unexplained loss in this system due to scattering or reflections. This waveguide and detector design therefore allows the placement of number-resolving single-photon detectors of predictable efficiency at arbitrary locations within a photonic circuit - a capability that offers great potential for many quantum optical applications.

Calkins, Brice; Mennea, Paolo L.; Lita, Adriana E.; Metcalf, Benjamin J.; Kolthammer, W. Steven; Lamas-Linares, Antia; Spring, Justin B.; Humphreys, Peter C.; Mirin, Richard P.; Gates, James C.; Smith, Peter G. R.; Walmsley, Ian A.; Gerrits, Thomas; Nam, Sae Woo

2013-09-01

55

High quantum-efficiency photon-number-resolving detector for photonic on-chip information processing.  

PubMed

The integrated optical circuit is a promising architecture for the realization of complex quantum optical states and information networks. One element that is required for many of these applications is a high-efficiency photon detector capable of photon-number discrimination. We present an integrated photonic system in the telecom band at 1550 nm based on UV-written silica-on-silicon waveguides and modified transition-edge sensors capable of number resolution and over 40 % efficiency. Exploiting the mode transmission failure of these devices, we multiplex three detectors in series to demonstrate a combined 79 % ± 2 % detection efficiency with a single pass, and 88 % ± 3 % at the operating wavelength of an on-chip terminal reflection grating. Furthermore, our optical measurements clearly demonstrate no significant unexplained loss in this system due to scattering or reflections. This waveguide and detector design therefore allows the placement of number-resolving single-photon detectors of predictable efficiency at arbitrary locations within a photonic circuit - a capability that offers great potential for many quantum optical applications. PMID:24104153

Calkins, Brice; Mennea, Paolo L; Lita, Adriana E; Metcalf, Benjamin J; Kolthammer, W Steven; Lamas-Linares, Antia; Spring, Justin B; Humphreys, Peter C; Mirin, Richard P; Gates, James C; Smith, Peter G R; Walmsley, Ian A; Gerrits, Thomas; Nam, Sae Woo

2013-09-23

56

Photon number amplification/duplication through parametric conversion  

NASA Technical Reports Server (NTRS)

The performance of parametric conversion in achieving number amplification and duplication is analyzed. It is shown that the effective maximum gains G(sub *) remain well below their integer ideal values, even for large signals. Correspondingly, one has output Fano factors F(sub *) which are increasing functions of the input photon number. On the other hand, in the inverse (deamplifier/recombiner) operating mode quasi-ideal gains G(sub *) and small factors F(sub *) approximately equal to 10 percent are obtained. Output noise and non-ideal gains are ascribed to spontaneous parametric emission.

Dariano, G. M.; Macchiavello, C.; Paris, M.

1993-01-01

57

Pump statistics and field squeezing in the extended Jaynes-Cummings model for a many m-photon CEL  

NASA Astrophysics Data System (ADS)

I extend the Jaynes-Cummings model for a many m-photon CEL recently obtained to a more general situation in which the upper atomic level is extended to m+1 almost degenerate levels, the ( n+m)-level atom interacts with a field via ( m+1)( n-1) m-photon processes. Based on the J-C model, and taking the pump statistics into consideration, we show that the photon number-squeezing of the many one-photon CEL also exists in the linear region of laser operation, and the squeezing increases with increasing upper atomic levels.

Huang, Hong-Bin

1995-02-01

58

Single photon laser altimeter simulator and statistical signal processing  

NASA Astrophysics Data System (ADS)

Spaceborne altimeters are common instruments onboard the deep space rendezvous spacecrafts. They provide range and topographic measurements critical in spacecraft navigation. Simultaneously, the receiver part may be utilized for Earth-to-satellite link, one way time transfer, and precise optical radiometry. The main advantage of single photon counting approach is the ability of processing signals with very low signal-to-noise ratio eliminating the need of large telescopes and high power laser source. Extremely small, rugged and compact microchip lasers can be employed. The major limiting factor, on the other hand, is the acquisition time needed to gather sufficient volume of data in repetitive measurements in order to process and evaluate the data appropriately. Statistical signal processing is adopted to detect signals with average strength much lower than one photon per measurement. A comprehensive simulator design and range signal processing algorithm are presented to identify a mission specific altimeter configuration. Typical mission scenarios (celestial body surface landing and topographical mapping) are simulated and evaluated. The high interest and promising single photon altimeter applications are low-orbit (˜10 km) and low-radial velocity (several m/s) topographical mapping (asteroids, Phobos and Deimos) and landing altimetry (˜10 km) where range evaluation repetition rates of ˜100 Hz and 0.1 m precision may be achieved. Moon landing and asteroid Itokawa topographical mapping scenario simulations are discussed in more detail.

Vacek, Michael; Prochazka, Ivan

2013-05-01

59

Observation of squeezed states with strong photon-number oscillations  

SciTech Connect

Squeezed states of light constitute an important nonclassical resource in the field of high-precision measurements, for example, gravitational wave detection, as well as in the field of quantum information, for example, for teleportation, quantum cryptography, and distribution of entanglement in quantum computation networks. Strong squeezing in combination with high purity, high bandwidth, and high spatial mode quality is desirable in order to achieve significantly improved performances contrasting any classical protocols. Here we report on the observation of 11.5 dB of squeezing, together with relatively high state purity corresponding to a vacuum contribution of less than 5%, and a squeezing bandwidth of about 170 MHz. The analysis of our squeezed states reveals a significant production of higher-order pairs of quantum-correlated photons and the existence of strong photon-number oscillations.

Mehmet, Moritz [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut) and Institut fuer Gravitationsphysik, Leibniz Universitaet Hannover, Callinstrasse 38, D-30167 Hannover (Germany); Centre for Quantum Engineering and Space-Time Research (QUEST), Leibniz Universitaet Hannover, Welfengarten 1, D-30167 Hannover (Germany); Vahlbruch, Henning; Lastzka, Nico; Danzmann, Karsten; Schnabel, Roman [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut) and Institut fuer Gravitationsphysik, Leibniz Universitaet Hannover, Callinstrasse 38, D-30167 Hannover (Germany)

2010-01-15

60

On-chip, photon-number-resolving, telecommunication-band detectors for scalable photonic information processing  

NASA Astrophysics Data System (ADS)

Integration is currently the only feasible route toward scalable photonic quantum processing devices that are sufficiently complex to be genuinely useful in computing, metrology, and simulation. Embedded on-chip detection will be critical to such devices. We demonstrate an integrated photon-number-resolving detector, operating in the telecom band at 1550 nm, employing an evanescently coupled design that allows it to be placed at arbitrary locations within a planar circuit. Up to five photons are resolved in the guided optical mode via absorption from the evanescent field into a tungsten transition-edge sensor. The detection efficiency is 7.2±0.5%. The polarization sensitivity of the detector is also demonstrated. Detailed modeling of device designs shows a clear and feasible route to reaching high detection efficiencies.

Gerrits, Thomas; Thomas-Peter, Nicholas; Gates, James C.; Lita, Adriana E.; Metcalf, Benjamin J.; Calkins, Brice; Tomlin, Nathan A.; Fox, Anna E.; Linares, Antía Lamas; Spring, Justin B.; Langford, Nathan K.; Mirin, Richard P.; Smith, Peter G. R.; Walmsley, Ian A.; Nam, Sae Woo

2011-12-01

61

Double galaxy redshifts and the statistics of small numbers  

NASA Technical Reports Server (NTRS)

Tifft (1980, 1982) claimed that observations of double galaxies reveal a 72 km/s periodicity. Sharp showed that the 'periodicities' in the observations are completely consistent with the statistics of small numbers. Here it is shown that Tifft's statistical procedure would ascribe a periodicity to small sets of Gaussian random noise. Satisfying the null hypothesis that the observations are not samples drawn from a normal population would require the acquisition of at least an order of magnitude more data.

Newman, William I.; Haynes, Martha P.; Terzian, Yervant

1989-01-01

62

Multiphoton communication in lossy channels with photon-number entangled states  

NASA Astrophysics Data System (ADS)

We address binary and quaternary communication channels based on correlated multiphoton two-mode states of radiation in the presence of losses. The protocol are based on photon number correlations and realized upon choosing a shared set of thresholds to convert the outcome of a joint photon number measurement into a symbol from a discrete alphabet. In particular, we focus on channels built using feasible photon-number entangled states (PNES) as two-mode coherently-correlated (TMC) or twin-beam (TWB) states and compare their performances with that of channels built using feasible classically correlated (separable) states. We found that PNES provide larger channel capacity in the presence of loss, and that TWB-based channels may transmit a larger amount of information than TMC-based ones at fixed energy and overall loss. Optimized bit discrimination thresholds, as well as the corresponding maximized mutual information, are explicitly evaluated as a function of the beam intensity and the loss parameter. The propagation of TMC and TWB in lossy channels is analyzed and the joint photon number distribution is evaluated, showing that the beam statistics, either sub-Poissonian for TMC or super-Poissonian for TWB, is not altered by losses. Although entanglement is not strictly needed to establish the channels, which are based on photon-number correlations owned also by separable mixed states, purity of the support state is relevant to increase security. The joint requirement of correlation and purity individuates PNES as a suitable choice to build effective channels. The effects of losses on channel security are briefly discussed.

Usenko, Vladyslav C.; Paris, Matteo G. A.

2007-04-01

63

Intensive statistical complexity measure of pseudorandom number generators  

NASA Astrophysics Data System (ADS)

A Statistical Complexity measure has been recently proposed to quantify the performance of chaotic Pseudorandom number generators (PRNG) (Physica A 354 (2005) 281). Here we revisit this quantifier and introduce two important improvements: (i) consideration of an intensive statistical complexity (Physica A 334 (2004) 119), and (ii) following the prescription of Brand and Pompe (Phys. Rev. Lett. 88 (2002) 174102-1) in evaluating the probability distribution associated with the PRNG. The ensuing new measure is applied to a very well-tested PRNG advanced by Marsaglia.

Larrondo, H. A.; González, C. M.; Martín, M. T.; Plastino, A.; Rosso, O. A.

2005-10-01

64

Generation of optical 'Schrödinger cats' from photon number states.  

PubMed

Schrödinger's cat is a Gedankenexperiment in quantum physics, in which an atomic decay triggers the death of the cat. Because quantum physics allow atoms to remain in superpositions of states, the classical cat would then be simultaneously dead and alive. By analogy, a 'cat' state of freely propagating light can be defined as a quantum superposition of well separated quasi-classical states-it is a classical light wave that simultaneously possesses two opposite phases. Such states play an important role in fundamental tests of quantum theory and in many quantum information processing tasks, including quantum computation, quantum teleportation and precision measurements. Recently, optical Schrödinger 'kittens' were prepared; however, they are too small for most of the aforementioned applications and increasing their size is experimentally challenging. Here we demonstrate, theoretically and experimentally, a protocol that allows the generation of arbitrarily large squeezed Schrödinger cat states, using homodyne detection and photon number states as resources. We implemented this protocol with light pulses containing two photons, producing a squeezed Schrödinger cat state with a negative Wigner function. This state clearly exhibits several quantum phase-space interference fringes between the 'dead' and 'alive' components, and is large enough to become useful for quantum information processing and experimental tests of quantum theory. PMID:17700695

Ourjoumtsev, Alexei; Jeong, Hyunseok; Tualle-Brouri, Rosa; Grangier, Philippe

2007-08-16

65

Photon-number-resolving decoy-state quantum key distribution  

SciTech Connect

In this paper, a photon-number-resolving decoy-state quantum key distribution (QKD) scheme is presented based on recent experimental advancements. A new upper bound on the fraction of counts caused by multiphoton pulses is given, which seems inherent as long as weak coherent sources and high lossy channel are used. This implies that our scheme is optimal in long-distance QKD with weak coherent sources. We show that Eve's coherent multiphoton pulse (CMP) attack is more efficient than a symmetric individual attack when the quantum bit error rate is small, so that the CMP attack should be considered to ensure the security of the final key. Our results show that a not-so-weak pulse can be used to transmit the key. Optimal intensity of the laser source is presented which provides a 23.9 km increase in the transmission distance.

Cai Qingyu [State Key Laboratory of Magnetic Resonances and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Tan Yonggang [State Key Laboratory of Magnetic Resonances and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Graduation University of Chinese Academy of Sciences, Beijing 100081 (China)

2006-03-15

66

On the Euclidean version of the photon number integral  

SciTech Connect

We reconsider the Euclidean version of the photon number integral introduced by Stodolsky [Acta Phys. Pol. B 33, 2659 (2002), e-print hep-th/02053131].This integral is well defined for any smooth non-self-intersecting curve in R{sup N}. Besides studying general features of this integral (including its conformal invariance), we evaluate it explicitly for the ellipse. The result is n{sub ellipse}=({xi}{sup -1}+{xi}){pi}{sup 2}, where {xi} is the ratio of the minor and major axes. This is in agreement with the previous result n{sub circle}=2{pi}{sup 2} and also with the conjecture that the minimum value of n for any plane curve occurs for the circle.

Ruijsenaars, S.; Stodolsky, L. [Department of Applied Mathematics, University of Leeds, Leeds LS2 9JT (United Kingdom); Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Foehringer Ring 6, 80805 Munich (Germany)

2008-02-15

67

Statistical issues in the analysis of DNA Copy Number Variations.  

PubMed

Approaches to assess copy number variation have advanced rapidly and are being incorporated into genetic studies. While the technology exists for CNV genotyping, a further understanding and discussion of how to use the CNV data for association analyses is warranted. We present the options available for processing and analysing CNV data. We break these steps down into choice of genotyping platform, normalisation of the array data, calling algorithm, and statistical analysis. PMID:19774103

Wineinger, Nathan E; Kennedy, Richard E; Erickson, Stephen W; Wojczynski, Mary K; Bruder, Carl E; Tiwari, Hemant K

2008-01-01

68

Physics and application of photon number resolving detectors based on superconducting parallel nanowires  

NASA Astrophysics Data System (ADS)

The parallel nanowire detector (PND) is a photon number resolving (PNR) detector that uses spatial multiplexing on a subwavelength scale to provide a single electrical output proportional to the photon number. The basic structure of the PND is the parallel connection of several NbN superconducting nanowires (?100 nm wide, a few nm thick), folded in a meander pattern. PNDs were fabricated on 3-4 nm thick NbN films grown on MgO (TS = 400 °C) substrates by reactive magnetron sputtering in an Ar/N2 gas mixture. The device performance was characterized in terms of speed and sensitivity. PNDs showed a counting rate of 80 MHz and a pulse duration as low as 660 ps full-width at half-maximum (FWHM). Building the histograms of the photoresponse peak, no multiplication noise buildup is observable. Electrical and optical equivalent models of the device were developed in order to study its working principle, define design guidelines and develop an algorithm to estimate the photon number statistics of an unknown light. In particular, the modeling provides novel insight into the physical limit to the detection efficiency and to the reset time of these detectors. The PND significantly outperforms existing PNR detectors in terms of simplicity, sensitivity, speed and multiplication noise.

Marsili, F.; Bitauld, D.; Gaggero, A.; Jahanmirinejad, S.; Leoni, R.; Mattioli, F.; Fiore, A.

2009-04-01

69

A Superposition Technique for Deriving Photon Scattering Statistics in Plane-Parallel Cloudy Atmospheres  

NASA Technical Reports Server (NTRS)

Photon transport in a multiple scattering medium is critically dependent on scattering statistics, in particular the average number of scatterings. A superposition technique is derived to accurately determine the average number of scatterings encountered by reflected and transmitted photons within arbitrary layers in plane-parallel, vertically inhomogeneous clouds. As expected, the resulting scattering number profiles are highly dependent on cloud particle absorption and solar/viewing geometry. The technique uses efficient adding and doubling radiative transfer procedures, avoiding traditional time-intensive Monte Carlo methods. Derived superposition formulae are applied to a variety of geometries and cloud models, and selected results are compared with Monte Carlo calculations. Cloud remote sensing techniques that use solar reflectance or transmittance measurements generally assume a homogeneous plane-parallel cloud structure. The scales over which this assumption is relevant, in both the vertical and horizontal, can be obtained from the superposition calculations. Though the emphasis is on photon transport in clouds, the derived technique is applicable to any scattering plane-parallel radiative transfer problem, including arbitrary combinations of cloud, aerosol, and gas layers in the atmosphere.

Platnick, S.

1999-01-01

70

Photon emission statistics and photon tracking in single-molecule spectroscopy of molecular aggregates: dimers and trimers.  

PubMed

Based on the generating function formalism, we investigate broadband photon statistics of emission for single dimers and trimers driven by a continuous monochromatic laser field. In particular, we study the first and second moments of the emission statistics, which are the fluorescence excitation line shape and Mandel's Q parameter. Numerical results for this line shape and the Q parameter versus laser frequency in the limit of long measurement times are obtained. We show that in the limit of small Rabi frequencies and laser frequencies close to resonance with one of the one-exciton states, the results for the line shape and Q parameter reduce to those of a two-level monomer. For laser frequencies halfway the transition frequency of a two-exciton state, the photon bunching effect associated with two-photon absorption processes is observed. This super-Poissonian peak is characterized in terms of the ratio between the two-photon absorption line shape and the underlying two-level monomer line shapes. Upon increasing the Rabi frequency, the Q parameter shows a transition from super- to sub- to super-Poissonian statistics. Results of broadband photon statistics are also discussed in the context of a transition (frequency) resolved photon detection scheme, photon tracking, which provides a greater insight in the different physical processes that occur in the multi-level systems. PMID:22713057

Bloemsma, E A; Knoester, J

2012-06-14

71

Effective atomic numbers for photon energy absorption and photon attenuation of tissues from human organs.  

PubMed

Effective atomic numbers for photon energy- absorption (Z(PEA)eff) and photon interaction (ZPI(eff)) of human organs and tissues such as cortical bone, ovary, eye lens, testis, breast tissue, adipose tissue, lung tissue, soft tissue, soft tissue, (4-component), blood (whole), brain (grey/white matter), and skeletal muscle have been calculated by a direct method in the energy region of 1 keV to 20 MeV. The ZPEAeff and ZPIeff values steadily increase, up to 8-50 keV, and steadily decrease up to 1.25-2.0 MeV for all of the substances studied. From 2.0 MeV, the values rise with the increase in energy, up to 20 MeV. Significant differences exist between the ZPIeff and ZPEAeff in the energy region of 20-400 keV and 3-20 MeV for cortical bone; 15-150 keV for soft tissue, ovary, testis, blood, brain, lung, and skeletal muscle; 15-100 keV for breast tissue, eye lens, and soft tissue (4-component); and 10-100 keV for adipose tissue. A maximum difference of 28.37% is observed at 100 keV for cortical bone, and 30.43% at 40 keV for adipose tissue. For ovary, eye lens, testis, breast tissue, lung tissue, soft tissue, soft tissue (4-component), blood (whole), brain (grey/white matter), and skeletal muscle, a maximum difference of 31.74%, 29.60%, 31.87%, 30.61%, 31.47%, 31.52%, 29.95%, 31.63%, 32.36%, and 31.42%, respectively, is seen at 50 keV. The energy positions at which the maximum of ZPEAeff and ZPIeff occurs differ. The single effective atomic number directly obtained using the program XMuDat (Z(XMUDATTeff)) are found to be higher compared to those of ZPEAeff and ZPIeff values. The effect of absorption edge on effective atomic numbers, and its variation with photon energy and the possibility of defining 2 set values of effective atomic numbers below the absorption edges of elements present in the organs and tissues, are discussed. PMID:12019959

Shivaramu

2002-01-01

72

Full photon statistics of a light beam transmitted through an optomechanical system  

NASA Astrophysics Data System (ADS)

In this paper, we study the full statistics of photons transmitted through an optical cavity coupled to nanomechanical motion. We analyze the entire temporal evolution of the photon correlations, the Fano factor, and the effects of strong laser driving, all of which show pronounced features connected to the mechanical backaction. In the regime of single-photon strong coupling, this allows us to predict a transition from sub-Poissonian to super-Poissonian statistics for larger observation time intervals. Furthermore, we predict cascades of transmitted photons triggered by multiphoton transitions. In this regime, we observe Fano factors that are drastically enhanced due to the mechanical motion.

Kronwald, Andreas; Ludwig, Max; Marquardt, Florian

2013-01-01

73

Advanced Photon Source research: Volume 1, Number 1, April 1998  

SciTech Connect

The following articles are included in this publication: (1) The Advanced Photon Source: A Brief Overview; (2) MAD Analysis of FHIT at the Structural Biology Center; (3) Advances in High-Energy-Resolution X-ray Scattering at Beamline 3-ID; (4) X-ray Imaging and Microspectroscopy of the Mycorrhyizal Fungus-Plant Symbiosis; (5) Measurement and Control of Particle-beam Trajectories in the Advanced Photon Storage Ring; (6) Beam Acceleration and Storage at the Advanced Photon Source; and (7) Experimental Facilities Operations and Current Status.

NONE

1998-04-01

74

Measurement of two-mode squeezing with photon number resolving multipixel detectors.  

PubMed

The measurement of the two-mode squeezed vacuum generated in an optical parametric amplifier (OPA) was performed with photon number resolving multipixel photon counters (MPPCs). Implementation of the MPPCs allows for the observation of noise reduction in a broad dynamic range of the OPA gain, which is inaccessible with standard single photon avalanche photodetectors. PMID:22825148

Kalashnikov, Dmitry A; Tan, Si-Hui; Iskhakov, Timur Sh; Chekhova, Maria V; Krivitsky, Leonid A

2012-07-15

75

Photon number states generated from a continuous-wave light source  

NASA Astrophysics Data System (ADS)

Conditional preparation of photon number states from a continuous-wave nondegenerate optical parametric oscillator is investigated. We derive the phase space Wigner function for the output state conditioned on photodetection events that are not necessarily simultaneous, and we maximize its overlap with the desired photon number state by choosing the optimal temporal output state mode function. We present a detailed numerical analysis for the case of two-photon state generation from a parametric oscillator driven with an arbitrary intensity below threshold, and in the low-intensity limit we present a formalism that yields the optimal output state mode function and fidelity for higher-photon-number states.

Nielsen, Anne E. B.; Mølmer, Klaus

2007-04-01

76

Photon Statistics of Atomic Fluorescence Near a Phase-conjugate Mirror or a Degenerate Parametric Amplifier  

Microsoft Academic Search

We have studied the modification of the photon statistics of the resonance fluorescence of a coherently driven two-state atom due to the presence of a phase-conjugate mirror (PCM) or a degenerate parametric amplifier (DPA). In both cases, we give explicit expressions for the n-fold intensity correlation function. We find that the photon statistics depends on the relative phase of the

B. H. W. Hendriks; G. Nienhuis

1989-01-01

77

Tomographic measurement of joint photon statistics of the twin-beam quantum state  

PubMed

We report the first measurement of the joint photon-number probability distribution for a two-mode quantum state created by a nondegenerate optical parametric amplifier. The measured distributions exhibit up to 1.9 dB of quantum correlation between the signal and idler photon numbers, whereas the marginal distributions are thermal as expected for parametric fluorescence. PMID:11018883

Vasilyev; Choi; Kumar; D'Ariano

2000-03-13

78

Streamline segment statistics of premixed flames with nonunity Lewis numbers  

NASA Astrophysics Data System (ADS)

The interaction of flame and surrounding fluid motion is of central importance in the fundamental understanding of turbulent combustion. It is demonstrated here that this interaction can be represented using streamline segment analysis, which was previously applied in nonreactive turbulence. The present work focuses on the effects of the global Lewis number (Le) on streamline segment statistics in premixed flames in the thin-reaction-zones regime. A direct numerical simulation database of freely propagating thin-reaction-zones regime flames with Le ranging from 0.34 to 1.2 is used to demonstrate that Le has significant influences on the characteristic features of the streamline segment, such as the curve length, the difference in the velocity magnitude at two extremal points, and their correlations with the local flame curvature. The strengthenings of the dilatation rate, flame normal acceleration, and flame-generated turbulence with decreasing Le are principally responsible for these observed effects. An expression for the probability density function (pdf) of the streamline segment length, originally developed for nonreacting turbulent flows, captures the qualitative behavior for turbulent premixed flames in the thin-reaction-zones regime for a wide range of Le values. The joint pdfs between the streamline length and the difference in the velocity magnitude at two extremal points for both unweighted and density-weighted velocity vectors are analyzed and compared. Detailed explanations are provided for the observed differences in the topological behaviors of the streamline segment in response to the global Le.

Chakraborty, Nilanjan; Wang, Lipo; Klein, Markus

2014-03-01

79

Streamline segment statistics of premixed flames with nonunity Lewis numbers.  

PubMed

The interaction of flame and surrounding fluid motion is of central importance in the fundamental understanding of turbulent combustion. It is demonstrated here that this interaction can be represented using streamline segment analysis, which was previously applied in nonreactive turbulence. The present work focuses on the effects of the global Lewis number (Le) on streamline segment statistics in premixed flames in the thin-reaction-zones regime. A direct numerical simulation database of freely propagating thin-reaction-zones regime flames with Le ranging from 0.34 to 1.2 is used to demonstrate that Le has significant influences on the characteristic features of the streamline segment, such as the curve length, the difference in the velocity magnitude at two extremal points, and their correlations with the local flame curvature. The strengthenings of the dilatation rate, flame normal acceleration, and flame-generated turbulence with decreasing Le are principally responsible for these observed effects. An expression for the probability density function (pdf) of the streamline segment length, originally developed for nonreacting turbulent flows, captures the qualitative behavior for turbulent premixed flames in the thin-reaction-zones regime for a wide range of Le values. The joint pdfs between the streamline length and the difference in the velocity magnitude at two extremal points for both unweighted and density-weighted velocity vectors are analyzed and compared. Detailed explanations are provided for the observed differences in the topological behaviors of the streamline segment in response to the global Le. PMID:24730945

Chakraborty, Nilanjan; Wang, Lipo; Klein, Markus

2014-03-01

80

Unified single-photon and single-electron counting statistics: From cavity QED to electron transport  

SciTech Connect

A key ingredient of cavity QED is the coupling between the discrete energy levels of an atom and photons in a single-mode cavity. The addition of periodic ultrashort laser pulses allows one to use such a system as a source of single photons--a vital ingredient in quantum information and optical computing schemes. Here we analyze and time-adjust the photon-counting statistics of such a single-photon source and show that the photon statistics can be described by a simple transport-like nonequilibrium model. We then show that there is a one-to-one correspondence of this model to that of nonequilibrium transport of electrons through a double quantum dot nanostructure, unifying the fields of photon-counting statistics and electron-transport statistics. This correspondence empowers us to adapt several tools previously used for detecting quantum behavior in electron-transport systems (e.g., super-Poissonian shot noise and an extension of the Leggett-Garg inequality) to single-photon-source experiments.

Lambert, Neill [Advanced Science Institute, RIKEN, Saitama 351-0198 (Japan); Chen, Yueh-Nan [Department of Physics and National Center for Theoretical Sciences, National Cheng-Kung University, Tainan 701, Taiwan (China); Nori, Franco [Advanced Science Institute, RIKEN, Saitama 351-0198 (Japan); Physics Department, University of Michigan, Ann Arbor, MI 48109-1040 (United States)

2010-12-15

81

Thwarting the photon-number-splitting attack with entanglement-enhanced BB84 quantum key distribution  

NASA Astrophysics Data System (ADS)

We develop an improvement to the weak laser pulse BB84 scheme for quantum key distribution, which utilizes entanglement to improve the security of the scheme and enhance its resilience to the photon-number-splitting attack. This protocol relies on the non-commutation of phase and number to detect an eavesdropper performing quantum non-demolition measurement on photon number. The potential advantages and disadvantages of this scheme are compared to the coherent decoy state protocol.

Sabottke, Carl F.; Richardson, Chris D.; Anisimov, Petr M.; Yurtsever, Ulvi; Lamas-Linares, Antia; Dowling, Jonathan P.

2012-04-01

82

Thwarting the photon number splitting attack with entanglement enhanced BB84 quantum key distribution  

NASA Astrophysics Data System (ADS)

We develop an improvement to the weak laser pulse BB84 scheme for quantum key distribution, which utilizes entanglement to increase the security of the scheme and enhance its resilience to the photon-number-splitting attack. This protocol relies on the non-commutation of phase and number to detect an eavesdropper performing quantum nondemolition measurement on photon number. The potential advantages and disadvantages of this scheme are compared to the coherent decoy state protocol.

Sabottke, Carl F.; Richardson, Chris D.; Anisimov, Petr M.; Yurtsever, Ulvi; Lamas-Linares, Antia; Dowling, Jonathan P.

2012-05-01

83

Talking Numbers: How Statistics Tell us Society's Story  

NSDL National Science Digital Library

Instructors at the Pensacola Junior College use this course to explain how social scientists use statistics to understand and explain theoretical concepts. Sociologists provide a cultural context for data and then illustrate how statistical equations use seemingly irrelevant mathematical concepts to measure and compare the behavior and trends of groups of people according to major categories: gender, race, class, religion, etc. Students can then understand how such statistical concepts are essential for quantifying and theorizing about society at large. Students and instructors can both explore this class, its syllabus, and the pertinent reading lists.

Shackelford, Monisa; Spencer, Sharon J.

2008-05-05

84

Proposal for a superconducting photon number resolving detector with large dynamic range.  

PubMed

We propose a novel photon number resolving detector structure with large dynamic range. It consists of the series connection of N superconducting nanowires, each connected in parallel to an integrated resistor. Photon absorption in a wire switches its current to the parallel resistor producing a voltage pulse and the sum of these voltages is measured at the output. The combination of this structure and a high input impedance preamplifier result in linear, high fidelity, and fast photon detection in the range from one to several tens of photons. PMID:22418306

Jahanmirinejad, Saeedeh; Fiore, Andrea

2012-02-27

85

Determination of the number of pulsed laser-Compton scattering photons  

NASA Astrophysics Data System (ADS)

We measured pulse-height spectra of 16.7 MeV laser-Compton scattering photons with a 6 in.×5 in. NaI(Tl) detector for blank and three lead materials of 75.8, 50.9, and 25.9% transmissions at the NewSUBARU facility to investigate how the original Poisson distribution of the pulsed photons is modified after passing through thick-target materials. We present a well-prescribed method of determining the number of incident photons within 3.5% accuracy based on the response of the NaI(Tl) detector to the pulsed photon beams.

Kondo, Takeo; Utsunomiya, Hiroaki; Akimune, Hidetoshi; Yamagata, Tamio; Okamoto, Akiyuki; Harada, Hideo; Kitatani, Fumito; Shima, Tatsushi; Horikawa, Ken; Miyamoto, Shuji

2011-12-01

86

Effect of Background Noise on the Photon Statistics of Triggered Single Molecules  

NASA Astrophysics Data System (ADS)

We theoretically derive exact expressions for Mandel's Q parameter of the triggered single molecular source, which is inferred from the probabilities PRS(n) using the record of each photon detection event based on Hanbury Brown and Twiss detection. The real triggered source is recognized as an ideal single photon source with a Poissonian statistics background. How to decrease the background and to increase the efficiency are discussed. It is established that the sub-Poissonian statistics formation can be determined by comparing the measured QRS of the real single triggered molecular with QC of the Poissonian source containing the same mean photons. By this method, we also give an efficient way to measure signal-to-background ratios of triggered single photons.

Xiao, Lian-Tuan; Zhao, Yan-Ting; Huang, Tao; Zhao, Jian-Ming; Yin, Wang-Bao; Jia, Suo-Tang

2004-03-01

87

Photon statistics, film preparation and characterization in fluorescent microthermal imaging  

SciTech Connect

Fluorescent microthermal imaging (FMI) involves coating a sample surface with a thin inorganic-based film that, upon exposure to uv light, emits temperature-dependent fluorescence. FMI offers the ability to create thermal maps of integrated circuits with a thermal resolution theoretically limited to 1 m{degree}C and a spatial resolution diffraction-limited to 0.3 {mu}m. Even though FMI has been in use for more than a decade, many factors that can affect the thermal image quality have not been studied well. This paper presents recent results showing the limitations from photon shot noise and the improvement in signal-to-noise ratio from signal averaging. Three important factors in film preparation and characterization are presented that have a significant impact on thermal quality and sensitivity of FMI: uv bleaching, film dilution, and film curing. It is shown how proper film preparation and data collection method can dramatically improve the quality of FMI thermal images.

Tangyunyong, Paiboon; Barton, D.L.

1995-08-01

88

Sub- and super-Poissonian photon statistics of single-molecule fluorescence blinking  

SciTech Connect

An analysis of intermittent fluorescence is presented for a single molecule driven by a continuous-wave laser field. The interruptions of fluorescence are caused by transition of the molecule to a triplet state. A method previously developed to calculate photon distribution for continuous-wave fluorescence is applied to analyze photon statistics of fluorescence blinking. The probability w{sub N}(T) of counting N photons over a time interval T is derived for intermittent fluorescence. The photons counted over relatively short intervals are found to have a sub-Poissonian (narrower than Poisson) distribution. The photon distribution over intervals longer than the mean off time has a complicated form with two maxima; i.e., a super-Poissonian (wider than Poisson) distribution is obtained.

Osad'ko, I. S. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)], E-mail: osadko@sci.lebedev.ru

2007-06-15

89

A simple method to determine effective atomic numbers of some compounds for multi-energetic photons  

NASA Astrophysics Data System (ADS)

A simple method has been presented for determination of effective atomic numbers (Zeff) in some compounds for multi-energetic photons such as Bremsstrahlung X-rays. Effective attenuation coefficient measurements were performed using a linear accelerator (Siemens Primus) which allows a good transmission geometry. Since the X-rays used are heterogeneous in energy, effective photon energies (Eeff) of the given compounds have been estimated first for 6 MV and 18 MV photons. Effective atomic cross-sections obtained from total mass attenuation coefficients have been used to estimate Eeff values. These Eeff values were then used to obtain Zeff values of the compounds for 6 MV and 18 MV photons. Finally, with the help of the present simple method it is possible to assign an effective atomic number of a multi-element material for multi-energetic Bremsstrahlung X-rays using the effective photon energies.

Kurudirek, Murat; Çelik, Alpdogan

2012-10-01

90

Practical photon number detection with electric field-modulated silicon avalanche photodiodes.  

PubMed

Low-noise single-photon detection is a prerequisite for quantum information processing using photonic qubits. In particular, detectors that are able to accurately resolve the number of photons in an incident light pulse will find application in functions such as quantum teleportation and linear optics quantum computing. More generally, such a detector will allow the advantages of quantum light detection to be extended to stronger optical signals, permitting optical measurements limited only by fluctuations in the photon number of the source. Here we demonstrate a practical high-speed device, which allows the signals arising from multiple photon-induced avalanches to be precisely discriminated. We use a type of silicon avalanche photodiode in which the lateral electric field profile is strongly modulated in order to realize a spatially multiplexed detector. Clearly discerned multiphoton signals are obtained by applying sub-nanosecond voltage gates in order to restrict the detector current. PMID:22273682

Thomas, O; Yuan, Z L; Shields, A J

2012-01-01

91

Random number generation based on the time of arrival of single photons  

NASA Astrophysics Data System (ADS)

We report the demonstration of a new type of true random number generator based on the random distribution of the time interval between photons from a single-photon-like source. The experimental setup is simple and robust against mechanical and temperature disturbances. With improved detector resolution and efficiency, the random number bit rate could be increased by more than an order of magnitude to satisfy practical requirements.

Ma, Hai-Qiang; Xie, Yuejian; Wu, Ling-An

2005-12-01

92

Eavesdropping on secure deterministic communication with qubits through photon-number-splitting attacks  

SciTech Connect

A collective photon-number-splitting attack strategy is proposed, which combines photon-number-splitting attack with an unambiguous set discrimination of quantum state. Verified by this attack strategy, it is shown that a two-way quantum secure direct communication protocol with qubits is insecure in real circumstance. Finally, we present a possible improved version of this kind of quantum secure direct communication protocol.

Lin Song [State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, Beijing 100876 (China); School of Mathematics and Computer Science, Fujian Normal University, Fuzhou 350007 (China); Wen Qiaoyan; Gao Fei [State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Zhu Fuchen [National Laboratory for Modern Communications, P.O. Box 810, Chengdu 610041 (China)

2009-05-15

93

Effective atomic numbers for photon energy absorption of some low- Z substances of dosimetric interest  

Microsoft Academic Search

Effective atomic numbers for photon energy absorption (Zpeaeff) and effective atomic numbers for photon interaction (Zpieff) of some low-Z substances of dosimetric interest such as A-150 tissue-equivalent plastic (A150TEP), alanine, bakelite, Gafchromic sensor (GS), plastic scintillator (PS), polyethylene, mylar, polystyrene, perspex, radiochromic dye film nylon base (RDF:NB), tissue-equivalent gas-methane based (TEG:MB) and tissue-equivalent gas-propane based (TEG:PB) have been calculated by

Shivaramu; R. Vijayakumar; L. Rajasekaran; N. Ramamurthy

2001-01-01

94

Learning to Read the Numbers: A Critical Orientation toward Statistics  

ERIC Educational Resources Information Center

Being a critical reader of data is an integral part of being fully literate in today's information age. In this article the authors underscore the interdisciplinary importance of this stance by drawing upon theoretical perspectives from both the fields of language and mathematics. They argue that all texts, including statistical ones, must be…

Whitin, Phyllis; Whitin, David J.

2008-01-01

95

USA by Numbers: A Statistical Portrait of the United States.  

ERIC Educational Resources Information Center

This book presents demographic data about a variety of U.S. public policies, social problems, and environmental issues. The issues and problems that the statistics illustrate (such as overflowing garbage dumps, homelessness, child poverty, and smog and water pollution) are connected with, and the consequences of, the expanding U.S. population. The…

Weber, Susan, Ed.

96

Modified nonclassical coherent state: Squeezing, antibunching, sub-Poissonian photon statistics, realization scheme with the {chi}{sup (2)}-nonlinearity, and generation of a macroscopic entangled state  

SciTech Connect

The nonlinear {chi}{sup (2)} Mach-Zehnder interferometer is proposed as a device for conditional generation of a modified coherent nonclassical state. We show that the generated macroscopic state exhibits nonclassical effects, such as squeezing, photon antibunching, and sub-Poissonian statistics. The modified coherent state generates a macroscopic entangled state. The scheme works without the photon number resolving detection but requires high-efficiency photodetectors. We explain the mechanism of generation of the modified coherent non-classical state.

Podoshvedov, S. A. [Korea Institute for Advanced Study, School of Computational Sciences (Korea, Republic of)], E-mail: sap@kias.re.kr

2007-04-15

97

Measurement of photon statistics with live photoreceptor cells.  

PubMed

We analyzed the electrophysiological response of an isolated rod photoreceptor of Xenopus laevis under stimulation by coherent and pseudothermal light sources. Using the suction-electrode technique for single cell recordings and a fiber optics setup for light delivery allowed measurements of the major statistical characteristics of the rod response. The results indicate differences in average responses of rod cells to coherent and pseudothermal light of the same intensity and also differences in signal-to-noise ratios and second-order intensity correlation functions. These findings should be relevant for interdisciplinary studies seeking applications of quantum optics in biology. PMID:23005626

Sim, Nigel; Cheng, Mei Fun; Bessarab, Dmitri; Jones, C Michael; Krivitsky, Leonid A

2012-09-14

98

Measurement of Photon Statistics with Live Photoreceptor Cells  

NASA Astrophysics Data System (ADS)

We analyzed the electrophysiological response of an isolated rod photoreceptor of Xenopus laevis under stimulation by coherent and pseudothermal light sources. Using the suction-electrode technique for single cell recordings and a fiber optics setup for light delivery allowed measurements of the major statistical characteristics of the rod response. The results indicate differences in average responses of rod cells to coherent and pseudothermal light of the same intensity and also differences in signal-to-noise ratios and second-order intensity correlation functions. These findings should be relevant for interdisciplinary studies seeking applications of quantum optics in biology.

Sim, Nigel; Cheng, Mei Fun; Bessarab, Dmitri; Jones, C. Michael; Krivitsky, Leonid A.

2012-09-01

99

Statistical Evaluation of PACSTAT Random Number Generation Capabilities.  

National Technical Information Service (NTIS)

This report summarizes the work performed in verifying the general purpose Monte Carlo driver-program PACSTAT. The main objective of the work was to verify the performance of PACSTAT's random number generation capabilities. Secondary objectives were to do...

G. F. Piepel M. R. Toland H. Harty M. J. Budden C. L. Bartley

1988-01-01

100

The Number of Guttman Errors as a Simple and Powerful Person-Fit Statistic.  

ERIC Educational Resources Information Center

Through simulation, the power of the U3 statistic was compared with the power of one of the simplest person-fit statistics, the sum of the number of Guttman errors. In most cases, a weighted version of the latter statistic performed as well as the U3 statistic. (SLD)

Meijer, Rob R.

1994-01-01

101

Time-domain diffuse optical tomography using analytic statistical characteristics of photon trajectories  

SciTech Connect

The inverse problem of diffuse optical tomography (DOT) is reduced by the method of photon average trajectories (PAT) to the solution of the integral equation integrated along the conditional mean statistical photon trajectory. The PAT bending near the flat boundary of a scattering medium is estimated analytically. These estimates are used to determine the analytic statistical characteristics of photon trajectories for the flat layer geometry. The inverse DOT problem is solved by using the multiplicative algebraic algorithm modified to improve the convergence of the iteration reconstruction process. The numerical experiment shows that the modified PAT method permits the reconstruction of near-surface optical inhomogeneities virtually without distortions. (special issue devoted to multiple radiation scattering in random media)

Konovalov, Aleksandr B; Vlasov, V V [E.I. Zababakhin All-Russian Scientific-Research Institute of Technical Physics, Russian Federal Nuclear Centre, Snezhinsk, Chelyabinsk region (Russian Federation); Kalintsev, A G; Lyubimov, Vladimir V [Research Institute for Laser Physics, St. Petersburg (Russian Federation); Kravtsenyuk, Olga V [Foundation for Research and Technology-Hellas (IESL-FORTH), Institute of Electronic Structure and Lasers, Crete (Greece)

2006-11-30

102

Photon statistics and polarization correlations at telecommunications wavelengths from a warm atomic ensemble  

NASA Astrophysics Data System (ADS)

We present measurements of the polarization correlation and photon statistics of photon pairs that emerge from a laser-pumped warm rubidium vapor cell. The photon pairs occur at 780 nm and 1367 nm and are polarization entangled. We measure the autocorrelation of each of the generated fields as well as the cross-correlation function, and observe a strong violation of the two-beam Cauchy-Schwartz inequality. We evaluate the performance of the system as source of heralded single photons at a telecommunication wavelength. We measure the heralded autocorrelation and see that coincidences are suppressed by a factor of ? 20 from a Poissonian source at a generation rate of 1500 s-1, a heralding efficiency of 10%, and a narrow spectral width.

Willis, R. T.; Becerra, F. E.; Orozco, L. A.; Rolston, S. L.

2011-07-01

103

Photon statistics and quantum fluctuations in a Collective Atomic Recoil Laser (CARL)  

NASA Astrophysics Data System (ADS)

We present a complete quantum mechanical treatment of the exponential instability of CARL. We show that the Glauber P function, in general, is the one that results from a superposition of a coherent probe field and the spontaneous emission chaotic field. In particular, if no probe is present the photon statistics during the exponential growth is that of a chaotic thermal field.

Bonifacio, Rodolfo

1998-01-01

104

Sub-shot-noise photon-number correlation in a mesoscopic twin beam of light  

SciTech Connect

We demonstrate sub-shot-noise photon-number correlations in a (temporal) multimode mesoscopic ({approx}10{sup 3} detected photons) twin beam produced by picosecond-pulsed spontaneous nondegenerate parametric down-conversion. We have separately detected the signal and idler distributions of photons collected in twin coherence areas and found that the variance of the photon-count difference goes below the shot-noise limit by 3.25 dB. The number of temporal modes contained in the twin beam, as well as the size of the twin coherence areas, depends on the pump intensity. Our scheme is based on spontaneous down-conversion and thus does not suffer from limitations due to the finite gain of the parametric process. Twin beams are also used to demonstrate the conditional preparation of a nonclassical (sub-Poissonian) state.

Bondani, Maria [National Laboratory for Ultrafast and Ultraintense Optical Science, C.N.R.-I.N.F.M., Como (Italy); Allevi, Alessia; Andreoni, Alessandra [C.N.R.-I.N.F.M.-C.N.I.S.M., Dipartimento di Fisica e Matematica, Universita dell'Insubria, Como (Italy); Zambra, Guido [Dipartimento di Fisica e Matematica, Universita dell'Insubria, Como (Italy); Dipartimento di Fisica dell'Universita di Milano, Milan (Italy); Paris, Matteo G. A. [Dipartimento di Fisica dell'Universita di Milano, Milan (Italy)

2007-07-15

105

Super-resolving single-photon number-path-entangled state and its generation  

NASA Astrophysics Data System (ADS)

In this paper, we propose two protocols for generating super-resolving single-photon (SRSP) number-path-entangled states from general maximally number-path-entangled NOON states. It is our purpose to show that, contrary to popular belief, a field in a single-photon state can carry multifold phase information. We also show that both protocols generate the desired state with different probabilities depending on the type of detectors being used. Such SRSP number-path-entangled states preserve high resolving power but lack the requirement of a multiphoton absorbing resist, which may serve as a proof-of-principle prototype for quantum lithography in the future.

Feng, Wei; Jiang, Kebei; Lollie, Michelle L.-J.; Zubairy, M. Suhail; Dowling, Jonathan P.

2014-04-01

106

Photon Statistics and Coherence in Light Emission from a Random Laser  

NASA Astrophysics Data System (ADS)

We derive the photon number probability distribution of light emitted from a random multiple-light-scattering medium with gain, using a generalized master equation. Our model treats the random laser medium as a collection of low quality-factor cavities, coupled by random photon diffusion. We demonstrate that, with stronger scattering, the pumping threshold for the transition from chaotic to isotropic coherent light emission decreases and the local second order coherence, above threshold, increases.

Florescu, Lucia; John, Sajeev

2004-07-01

107

Advance Data from Vital and Health Statistics of the National Center for Health Statistics: Number 195.  

National Technical Information Service (NTIS)

The National Center for Health Statistics has included questions about acquired immunodeficiency syndrome (AIDS) in the National Health Interview Survey (NHIS) since 1987. Data concerning the adult population's knowledge and attitudes about AIDS and trans...

J. E. Fitti M. Cynamon

1990-01-01

108

Statistical evaluation of PACSTAT random number generation capabilities  

SciTech Connect

This report summarizes the work performed in verifying the general purpose Monte Carlo driver-program PACSTAT. The main objective of the work was to verify the performance of PACSTAT's random number generation capabilities. Secondary objectives were to document (using controlled configuration management procedures) changes made in PACSTAT at Pacific Northwest Laboratory, and to assure that PACSTAT input and output files satisfy quality assurance traceability constraints. Upon receipt of the PRIME version of the PACSTAT code from the Basalt Waste Isolation Project, Pacific Northwest Laboratory staff converted the code to run on Digital Equipment Corporation (DEC) VAXs. The modifications to PACSTAT were implemented using the WITNESS configuration management system, with the modifications themselves intended to make the code as portable as possible. Certain modifications were made to make the PACSTAT input and output files conform to quality assurance traceability constraints. 10 refs., 17 figs., 6 tabs.

Piepel, G.F.; Toland, M.R.; Harty, H.; Budden, M.J.; Bartley, C.L.

1988-05-01

109

Photon counting statistics for blinking CdSe-ZnS quantum dots: a Lévy walk process.  

PubMed

We analyze photon statistics of blinking CdSe-ZnS nanocrystals interacting with a continuous wave laser field, showing that the process is described by a ballistic Lévy walk. In particular, we show that Mandel's Q parameter, describing the fluctuations of the photon counts, is increasing with time even in the limit of long time. This behavior is in agreement with the theory of Silbey and co-workers (Jung et al. Chem. Phys. 2002, 284, 181), and in contrast to all existing examples where Q approaches a constant, independent of time in the long time limit. We then analyze the distribution of the time averaged intensities, showing that they exhibit a nonergodic behavior, namely, the time averages remain random even in the limit of a long measurement time. In particular, the distribution of occupation times in the on-state compares favorably to a theory of weak ergodicity breaking of blinking nanocrystals. We show how our data analysis yields information on the amplitudes of power-law decaying on and off time distributions, information not available using standard data analysis of on and off time histograms. Photon statistics reveals fluctuations in the intensity of the bright state indicating that it is composed of several states. Photon statistics exhibits a Lévy walk behavior also when an ensemble of 100 dots is investigated, indicating that the strange kinetics can be observed already at the level of small ensembles. PMID:16986903

Margolin, G; Protasenko, V; Kuno, M; Barkai, E

2006-09-28

110

Numbers of scintillation photons produced in NaI(Tl) and plastic scintillator by gamma rays  

SciTech Connect

The W[sub s]-value, which is defined as an average energy expended per scintillation photon, was determined to be 17.2 [+-] 0.40 eV for a NaI(Tl) phosphor and 60.8 [+-] 4.3 eV for a plastic scintillator (NE-102A). Those were obtained from the numbers of photoelectrons measured with several combinations of a photomultiplier tube and a NaI(Tl) or a NE-102A scintillator. The number of photoelectrons, which was measured by the photomultiplier tube as a vacuum photodiode, was converted to the number of scintillation photons by using an averaged quantum efficiency (Q[sub e]) of each photomultiplier photocathode and a calculated collection efficiency (f[sub c]) of the scintillation photons at the photocathode. However, the above values do not include the uncertainties due to the not known exact emission spectra and the photomultiplier response curves.

Miyajima, M.; Sasaki, S.; Tawara, H. (National Lab. for High Energy Physics, Tsukuba (Japan))

1993-08-01

111

Statistical connection of binomial photon counting and photon averaging in high dynamic range beam-scanning microscopy.  

PubMed

Data from photomultiplier tubes are typically analyzed using either counting or averaging techniques, which are most accurate in the dim and bright signal limits, respectively. A statistical means of adjoining these two techniques is presented by recovering the Poisson parameter from averaged data and relating it to the statistics of binomial counting from Kissick et al. [Anal. Chem. 82, 10129 (2010)]. The point at which binomial photon counting and averaging have equal signal to noise ratios is derived. Adjoining these two techniques generates signal to noise ratios at 87% to approaching 100% of theoretical maximum across the full dynamic range of the photomultiplier tube used. The technique is demonstrated in a second harmonic generation microscope. PMID:22535131

Muir, Ryan D; Kissick, David J; Simpson, Garth J

2012-04-23

112

Cavity nonlinear optics at low photon numbers from collective atomic motion.  

PubMed

We report on Kerr nonlinearity and dispersive optical bistability of a Fabry-Perot optical resonator due to the displacement of ultracold atoms trapped within. In the driven resonator, such collective motion is induced by optical forces acting upon up to 10(5) 87Rb atoms prepared in the lowest band of a one-dimensional intracavity optical lattice. The longevity of atomic motional coherence allows for strongly nonlinear optics at extremely low cavity photon numbers, as demonstrated by the observation of both branches of optical bistability at photon numbers below unity. PMID:18233217

Gupta, Subhadeep; Moore, Kevin L; Murch, Kater W; Stamper-Kurn, Dan M

2007-11-23

113

Cavity Nonlinear Optics at Low Photon Numbers from Collective Atomic Motion  

SciTech Connect

We report on Kerr nonlinearity and dispersive optical bistability of a Fabry-Perot optical resonator due to the displacement of ultracold atoms trapped within. In the driven resonator, such collective motion is induced by optical forces acting upon up to 10{sup 5} {sup 87}Rb atoms prepared in the lowest band of a one-dimensional intracavity optical lattice. The longevity of atomic motional coherence allows for strongly nonlinear optics at extremely low cavity photon numbers, as demonstrated by the observation of both branches of optical bistability at photon numbers below unity.

Gupta, Subhadeep; Moore, Kevin L.; Murch, Kater W. [Department of Physics, University of California, Berkeley, California 94720 (United States); Stamper-Kurn, Dan M. [Department of Physics, University of California, Berkeley, California 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2007-11-23

114

Two models for rapidly calculating bidirectional reflectance of complex vegetation scenes: Photon spread (PS) model and statistical photon spread (SPS) model  

Microsoft Academic Search

Two computationally fast Monte Carlo algorithms (models) are described for calculating the bidirectional reflectance factors (BRFs) from architecturally realistic canopies and from statistically characterized canopies. Both methods use a novel concept, called photon spreading. In this technique, the photon is treated as a particle when it travels through the canopy, but with each collision it is also treated like a

Richard L. Thompson; Narendra S. Goel

1998-01-01

115

Classical light sources with tunable temporal coherence and tailored photon number distributions  

NASA Astrophysics Data System (ADS)

We demonstrate a method of obtaining, from coherent light, tunable classical light where the temporal characteristics and photon number distribution can be controlled electronically. The tunability of the temporal coherence is shown through second-order correlation ( G 2( ?)) measurements, both in the continuous intensity measurement as well as in the photon counting regime. The generation of desired classical photon number distributions is illustrated by creating two light sources —one emitting a thermal state and the other a specific classical non-Gaussian state. Such tailored light sources with emission characteristics quite different from those of existing natural light sources are likely to be useful in quantum information processing, for example, in conjunction with photon addition, to generate tailored non-classical states of light with desired photon number distributions. As a particular application in this direction we also outline how a tailored classical non-Gaussian state generated by our technique may be mixed with a non-classical Gaussian state at a beamsplitter, to generate novel forms of non-Gaussian entanglement.

Pandey, Deepak; Satapathy, Nandan; Suryabrahmam, Buti; Ivan, J. Solomon; Ramachandran, Hema

2014-06-01

116

Qubit-photon interactions in a cavity: Measurement-induced dephasing and number splitting  

SciTech Connect

We theoretically study measurement-induced dephasing of a superconducting qubit in the circuit QED architecture and compare the results to those obtained experimentally by Schuster et al. [Phys. Rev. Lett. 94, 123602 (2005)]. Strong coupling of the qubit to the resonator leads to a significant ac Stark shift of the qubit transition frequency. As a result, quantum fluctuations in the photon number populating the resonator cause dephasing of the qubit. We find good agreement between the predicted line shape of the qubit spectrum and the experimental results. Furthermore, in the strongly dispersive limit, where the Stark shift per photon is large compared to the cavity decay rate and the qubit linewidth, we predict that the qubit spectrum will be split into multiple peaks, with each peak corresponding to a different number of photons in the cavity.

Gambetta, Jay; Schuster, D. I.; Frunzio, L.; Majer, J.; Devoret, M. H.; Girvin, S. M.; Schoelkopf, R. J. [Department of Applied Physics and Department of Physics, Yale University, New Haven, Connecticut 06520 (United States); Blais, Alexandre [Department of Applied Physics and Department of Physics, Yale University, New Haven, Connecticut 06520 (United States); Departement de Physique et Regroupement Quebecois sur les Materiaux de Pointe, Universite de Sherbrooke, Sherbrooke, Quebec, J1K 2R1 (Canada); Wallraff, A. [Department of Applied Physics and Department of Physics, Yale University, New Haven, Connecticut 06520 (United States); Department of Physics, ETH Zurich, CH-8093 Zurich (Switzerland)

2006-10-15

117

Passive decoy state SARG04 quantum-key-distribution with practical photon-number resolving detectors  

NASA Astrophysics Data System (ADS)

SARG04 protocol has its advantages in defending photon number splitting attack, benefited from two-photon pulses part. In this paper, we present a passive decoy state SARG04 scheme combining with practical photon number resolving (PNR) detectors. Two kinds of practical detectors, transition-edge sensor and time-multiplexing detector, are taken into consideration. Theoretical analysis shows that both of them are compatible with the passive decoy state SARG04. Compared with the original SARG04, two detectors can boost the key generation rate and maximal secure distance obviously. Meanwhile, the result shows that quantum efficiency and dark count of the detector influence the maximal distance slightly, which indicates the prospect of implementation in real quantum key distribution system with imperfect practical PNS detectors.

Xu, Fang-Xing; Wang, Shuang; Han, Zheng-Fu; Guo, Guang-Can

2010-10-01

118

The number of accumulated photons and the quality of stimulated emission depletion lifetime images.  

PubMed

Time binning is used to increase the number of photon counts in the peak channel of stimulated emission depletion fluorescence lifetime decay curves to determine how it affects the resulting lifetime image. The fluorescence lifetime of the fluorophore, Alexa Fluor 594 phalloidin, bound to F-actin is probed in cultured S2 cells at a spatial resolution of ~40 nm. This corresponds to a 10-fold smaller probe volume compared to confocal imaging, and a reduced number of photons contributing to the signal. Pixel-by-pixel fluorescence lifetime measurements and error analysis show that an average of 40 ± 30 photon counts in the peak channel with a signal-to-noise ratio of 20 is enough to calculate a reliable fluorescence lifetime from a single exponential fluorescence decay. No heterogeneity in the actin cytoskeleton in different regions of the cultured cells was measured in the 40-400 nm spatial regime. PMID:24506181

Syed, Aleem; Lesoine, Michael D; Bhattacharjee, Ujjal; Petrich, Jacob W; Smith, Emily A

2014-07-01

119

Lacunary Statistical and Lacunary Strongly Convergence of Generalized Difference Sequences of Fuzzy Numbers  

Microsoft Academic Search

The purpose of this paper is to introduce the concepts of lacunary statistical convergence and lacunary strongly convergence of generalized difference sequences of fuzzy numbers. We give some relations related to these concepts. We show that lacunary ?m-statistical convergence and lacunary strongly ?(p)m-convergence are equivalent for ?m-bounded sequences of fuzzy numbers. We also introduce the concept of lacunary ?m-statistically Cauchy

Yavuz Altin; Mikail Et; Rifat Çolak

2006-01-01

120

Pulse pileup statistics for energy discriminating photon counting x-ray detectors  

SciTech Connect

Purpose: Energy discriminating photon counting x-ray detectors can be subject to a wide range of flux rates if applied in clinical settings. Even when the incident rate is a small fraction of the detector's maximum periodic rate N{sub 0}, pulse pileup leads to count rate losses and spectral distortion. Although the deterministic effects can be corrected, the detrimental effect of pileup on image noise is not well understood and may limit the performance of photon counting systems. Therefore, the authors devise a method to determine the detector count statistics and imaging performance. Methods: The detector count statistics are derived analytically for an idealized pileup model with delta pulses of a nonparalyzable detector. These statistics are then used to compute the performance (e.g., contrast-to-noise ratio) for both single material and material decomposition contrast detection tasks via the Cramer-Rao lower bound (CRLB) as a function of the detector input count rate. With more realistic unipolar and bipolar pulse pileup models of a nonparalyzable detector, the imaging task performance is determined by Monte Carlo simulations and also approximated by a multinomial method based solely on the mean detected output spectrum. Photon counting performance at different count rates is compared with ideal energy integration, which is unaffected by count rate. Results: The authors found that an ideal photon counting detector with perfect energy resolution outperforms energy integration for our contrast detection tasks, but when the input count rate exceeds 20%N{sub 0}, many of these benefits disappear. The benefit with iodine contrast falls rapidly with increased count rate while water contrast is not as sensitive to count rates. The performance with a delta pulse model is overoptimistic when compared to the more realistic bipolar pulse model. The multinomial approximation predicts imaging performance very close to the prediction from Monte Carlo simulations. The monoenergetic image with maximum contrast-to-noise ratio from dual energy imaging with ideal photon counting is only slightly better than with dual kVp energy integration, and with a bipolar pulse model, energy integration outperforms photon counting for this particular metric because of the count rate losses. However, the material resolving capability of photon counting can be superior to energy integration with dual kVp even in the presence of pileup because of the energy information available to photon counting. Conclusions: A computationally efficient multinomial approximation of the count statistics that is based on the mean output spectrum can accurately predict imaging performance. This enables photon counting system designers to directly relate the effect of pileup to its impact on imaging statistics and how to best take advantage of the benefits of energy discriminating photon counting detectors, such as material separation with spectral imaging.

Wang, Adam S.; Harrison, Daniel; Lobastov, Vladimir; Tkaczyk, J. Eric [Departments of Electrical Engineering and Radiology, Stanford University, Stanford, California 94305 (United States); GE Global Research Center, Niskayuna, New York 12309 (United States)

2011-07-15

121

Quantum cryptography protocols robust against photon number splitting attacks for weak laser pulse implementations.  

PubMed

We introduce a new class of quantum key distribution protocols, tailored to be robust against photon number splitting (PNS) attacks. We study one of these protocols, which differs from the original protocol by Bennett and Brassard (BB84) only in the classical sifting procedure. This protocol is provably better than BB84 against PNS attacks at zero error. PMID:14995344

Scarani, Valerio; Acín, Antonio; Ribordy, Grégoire; Gisin, Nicolas

2004-02-01

122

Soliton-collision interferometer for the quantum nondemolition measurement of photon number: numerical results.  

PubMed

Using analytic theory and numerical experiments, we show that a quantum nondemolition measurement of the photon number of optical solitons in a single-mode optical fiber can be made. We describe the soliton-collision interferometer with which we propose to make this measurement and discuss simulations of the performance of this interferometer. PMID:19759769

Sakai, Y; Hawkins, R J; Friberg, S R

1990-02-15

123

Optimal sub-Poissonian light generation from twin beams by photon-number resolving detectors  

NASA Astrophysics Data System (ADS)

We generate nonclassical conditional states by exploiting the quantum correlations of multi-mode twin-beam states endowed with a sizeable number of photons. A strong relation between the sub-shot-noise correlations exhibited by twin beams and the sub-Poissonian character of the conditional states is experimentally revealed. It determines optimal conditions for sub-Poissonian light generation.

Lamperti, Marco; Allevi, Alessia; Bondani, Maria; Machulka, Radek; Michálek, Václav; Haderka, Ond?ej; Pe?ina, Jan

2014-01-01

124

Photon-number superselection and the entangled coherent-state representation  

SciTech Connect

We introduce the entangled coherent-state representation, which provides a powerful technique for efficiently and elegantly describing and analyzing quantum optics sources and detectors while respecting the photon-number superselection rule that is satisfied by all known quantum optics experiments. We apply the entangled coherent-state representation to elucidate and resolve the long-standing puzzles of the coherence of a laser output field, interference between two number states, and dichotomous interpretations of quantum teleportation of coherent states.

Sanders, Barry C.; Bartlett, Stephen D.; Rudolph, Terry; Knight, Peter L. [Department of Physics, Macquarie University, Sydney, New South Wales 2109 (Australia); Bell Laboratories, 600-700 Mountain Avenue, Murray Hill, New Jersey 07974 (United States); Optics Section, Blackett Laboratory, Imperial College London, London SW7 2BZ (United Kingdom)

2003-10-01

125

Generation of optical coherent-state superpositions by number-resolved photon subtraction from the squeezed vacuum  

SciTech Connect

We have created heralded coherent-state superpositions (CSSs) by subtracting up to three photons from a pulse of squeezed vacuum light. To produce such CSSs at a sufficient rate, we used our high-efficiency photon-number-resolving transition edge sensor to detect the subtracted photons. This experiment is enabled by and utilizes the full photon-number-resolving capabilities of this detector. The CSS produced by three-photon subtraction had a mean-photon number of 2.75{sub -0.24}{sup +0.06} and a fidelity of 0.59{sub -0.14}{sup +0.04} with an ideal CSS. This confirms that subtracting more photons results in higher-amplitude CSSs.

Gerrits, Thomas; Glancy, Scott; Clement, Tracy S.; Calkins, Brice; Lita, Adriana E.; Nam, Sae Woo; Mirin, Richard P.; Knill, Emanuel [National Institute of Standards and Technology, Boulder, Colorado 80305 (United States); Miller, Aaron J. [Albion College, Albion, Michigan 49224 (United States); Migdall, Alan L. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Joint Quantum Institute, University of Maryland, College Park, Maryland 20742 (United States)

2010-09-15

126

Statistical Properties of the Generalized Photon-Added Pair Coherent State  

NASA Astrophysics Data System (ADS)

We present a class of generalized photon-added pair coherent states (GPAPCS) and analyze some prominent nonclassical properties such as sub-Poissonian distribution and violations of Cauchy-Schwarz inequalities. In addition, we derive that the Wigner function of GPAPCS involves correlation of two two-variable Hermite polynomials and its Husimi function is related to a two-variable Hermite polynomial. Their behaviors varying with the phase space parameters are also graphically discussed. We find that the nonclassical effects of GPAPCS exhibits more with increasing of excitation photon numbers.

Yuan, Hong-Chun; Xu, Xue-Xiang; Fan, Hong-Yi

2009-12-01

127

Quantum Key Distribution Using Vacuum-One-Photon Qubits: Maximum Number of Transferable Bits per Particle  

NASA Astrophysics Data System (ADS)

Quantum key distribution schemes which employ encoding on vacuum-one-photon qubits are capable of transferring more information bits per particle than the standard schemes employing polarization or phase coding. We calculate the maximum number of classical bits per particle that can be securely transferred when the key distribution is performed with the BB84 and B92 protocols, respectively, using the vacuum-one-photon qubits. In particular, we show that for a generalized B92 protocol with the vacuum-one-photon qubits, a maximum of two bits per particle can be securely transferred. We also demonstrate the advantage brought about by performing a generalized measurement that is optimized for unambiguous discrimination of the encoded states: the parameter range where the transfer of two bits per particle can be achieved is dramatically enhanced as compared to the corresponding parameter range of projective measurements.

Lee, Su-Yong; Ji, Se-Wan; Lee, Hai-Woong; Lee, Jae-Weon; Bergou, János A.

2009-09-01

128

Photonic analog-to-digital converter based on the robust symmetrical number system  

NASA Astrophysics Data System (ADS)

A novel approach to realizing photonic analog-to-digital conversion with Gray-code-like property is proposed and demonstrated. Instead of using Mach-Zehnder modulators (MZMs) with different half-wave voltages, an array of MZMs with identical half-wave voltages are applied to realize quantization and encoding, which greatly simplifies the implementation. Multiple comparators with preset thresholds are applied at the output of each MZM to improve the number of bits. Through properly setting the bias voltages of the MZMs, a photonic analog to digital converter (ADC) based on the robust symmetrical number system (RSNS) coding method is realized. As an example, a 3-channel structure with maximum quantization level of 17 (corresponding to 4.09 bits) is investigated in detail. We show that the differential encoding technique can be applied in the proposed structure, which increases the equivalent number of bits of the ADC system.

Chen, Ying; Chi, Hao; Zheng, Shilie; Jin, Xiaofeng; Zhang, Xianmin

2012-11-01

129

Effective atomic numbers for photon energy absorption of some low- Z substances of dosimetric interest  

NASA Astrophysics Data System (ADS)

Effective atomic numbers for photon energy absorption (Z PEAeff) and effective atomic numbers for photon interaction (Z PIeff) of some low- Z substances of dosimetric interest such as A-150 tissue-equivalent plastic (A150TEP), alanine, bakelite, Gafchromic sensor (GS), plastic scintillator (PS), polyethylene, mylar, polystyrene, perspex, radiochromic dye film nylon base (RDF : NB), tissue-equivalent gas-methane based (TEG : MB) and tissue-equivalent gas-propane based (TEG : PB) have been calculated by a direct method in the energy region of 1 keV-20 MeV. Experimental mass attenuation coefficients and Z PIeff of some of these substances at selected photon energies of 26.34, 33.2, and 59.54 keV have been obtained and compared with theoretical values. The Z PEAeff and Z PIeff values steadily increases up to 6-15 keV, and then they steadily decrease up to 600-1500 keV for all the substances studied. From 1.5 MeV, the values increases with increase in energy up to 20 MeV. Significant differences up to 33.68% exist between Z PIeff and the Z PEAeff in the energy region of 10-150 keV. The single effective atomic numbers obtained using the program XMuDat (Z XMUDATeff ) are found to be significantly higher compared to those of Z PEAeff and Z PIeff values in the entire energy of interest for all the substances studied. The directly calculated Z PEAeff and Z PIeff values vary with energy compared to the energy-independent effective atomic numbers predicted by various theoretical expressions. The effects of absorption edges on effective atomic numbers and their variation with photon energy and the possibility of defining two set values of effective atomic numbers below the absorption edges of elements present in the composite substances are discussed.

Shivaramu,; Vijayakumar, R.; Rajasekaran, L.; Ramamurthy, N.

2001-12-01

130

Results from statistical analysis of popular pseudorandom number generators for simulation  

Microsoft Academic Search

Assuming that the number of replicates r and the number of random numbers ni for each input variate sample are known to reach the required accuracy on simulation outputs, and that goodness-of-fit techniques test results are observed, we investigate possible interpretations of these results based on known bounds in probability and statistical analysis, and explore the relationship between input and

Paul Labbe; M.-J. Bureau

1993-01-01

131

Pulse pileup statistics for energy sensitive photon counting detectors with pulse height analysis  

NASA Astrophysics Data System (ADS)

Photon counting statistics with pulse pileup effects (PPE) have been investigated for detection schemes with two assumptions: a fixed deadtime (i.e., non-paralyable and paralyzable detection schemes) and a delta pulse shape. Analytical expressions have been developed which shed light on interesting findings: (1) the variance becomes smaller than mean with PPE; and (2) the variance-to-mean ratio (VMR) of narrow energy windows remains very close to 1. In this study, we experimentally investigate VMR with PPE with a variable deadtime (i.e., pulse height analysis) and bipolar and unipolar pulse shapes with a long tail in addition to the above cases. We will use Monte Carlo simulation for a systematic study and a physical photon counting detector to confirm the results.

Taguchi, Katsuyuki; Srivastava, Somesh; Tang, Qiulin; Caffo, Brian S.; Iwanczyk, Jan S.; Hartsough, Neal E.; Barber, William C.; Cammin, Jochen

2012-02-01

132

Photon-number entangled states generated in Kerr media with optical parametric pumping  

NASA Astrophysics Data System (ADS)

Two nonlinear Kerr oscillators mutually coupled by parametric pumping are studied as a source of states entangled in photon numbers. Temporal evolution of entanglement quantified by negativity shows the effects of sudden death and birth of entanglement. Entanglement is preserved even in asymptotic states under certain conditions. The role of reservoirs at finite temperature in entanglement evolution is elucidated. Relation between generation of entangled states and violation of Cauchy-Schwartz inequality for oscillator intensities is found.

Kowalewska-Kud?aszyk, A.; Leo?ski, W.; Pe?ina, Jan, Jr.

2011-05-01

133

Photon-number entangled states generated in Kerr media with optical parametric pumping  

SciTech Connect

Two nonlinear Kerr oscillators mutually coupled by parametric pumping are studied as a source of states entangled in photon numbers. Temporal evolution of entanglement quantified by negativity shows the effects of sudden death and birth of entanglement. Entanglement is preserved even in asymptotic states under certain conditions. The role of reservoirs at finite temperature in entanglement evolution is elucidated. Relation between generation of entangled states and violation of Cauchy-Schwartz inequality for oscillator intensities is found.

Kowalewska-Kudlaszyk, A.; Leonski, W.; Perina, Jan Jr. [Nonlinear Optics Division, Department of Physics, Adam Mickiewicz University, Umultowska 85, PL-61-614 Poznan (Poland)

2011-05-15

134

High Speed Photon Number Resolving Detector with Titanium Transition Edge Sensor  

Microsoft Academic Search

We have developed new photon number resolving detectors with titanium transition edge sensors (Ti-TESs) for a high counting\\u000a rate operation in quantum information. The titanium superconducting films were fabricated by ultra-high vacuum electron beam\\u000a evaporation, and showed a sharp superconducting transition at 359 mK. The device was coupled to a single mode optical fiber,\\u000a and cooled down to 100 mK. Some of

D. Fukuda; G. Fujii; A. Yoshizawa; H. Tsuchida; R. M. T. Damayanthi; H. Takahashi; S. Inoue; M. Ohkubo

2008-01-01

135

True random number generator based on discretized encoding of the time interval between photons.  

PubMed

We propose an approach to generate true random number sequences based on the discretized encoding of the time interval between photons. The method is simple and efficient, and can produce a highly random sequence several times longer than that of other methods based on threshold or parity selection, without the need for hashing. A proof-of-principle experiment has been performed, showing that the system could be easily integrated and applied to quantum cryptography and other fields. PMID:23456008

Li, Shen; Wang, Long; Wu, Ling-An; Ma, Hai-Qiang; Zhai, Guang-Jie

2013-01-01

136

Characteristics of Noise and Photon Statistics of Fiber Components in Electro-Optical Systems  

NASA Astrophysics Data System (ADS)

This thesis presents a comprehensive study of the role of the fiber replicator in electro-optical systems. In the all fiber optical diagnostic system for the National Ignition Facility's DANTE data acquisition system running at 1550nm, the 8x fiber replicator was used to increase the SNR (Signal to Noise Ratio) of single-shot, electrical pulse measurements. In the system, Mach-Zehnder modulators were used to convert the electrical signals into optical signals. The fiber replicator was used to create identical copies of the optical signals. A High SNR was achieved through the averaging of these duplicated signals. Erbium-doped fiber amplifiers (EDFAs) were built to amplify the optical signals after the fiber replicator. The EDFAs applied in the DANTEEO system should have high gain, low noise, low background signals and high pulse-shape fidelity. In this thesis, we discussed the effect of different configurations and the type of Er-doped fibers on the gain and noise performance of EDFAs. We also used a simplified model for dynamic gain in EDFAs to explore the effect of the EDFA on the shape of the amplified pulse. Based on this model, the calculated pulse-shape distortions were found to be dependent on the EDFA configuration and the optical gain. We also investigated the photon statistics with the fiber replicator in a photon entanglement system. The entangled photons were created through the up-conversion and down-conversion of a Q-switch laser beam running at 1053nm. The different behavior between entangled photon and non-entangled single photons in the system with the fiber replicator are discussed.

Zhao, Cheng

137

Probabilistic and statistical relationships between number of vehicles and number of visitors at a geologic site in a National Park  

USGS Publications Warehouse

The National Park Service needs to establish in all of the national parks how large the parking lots should be in order to enjoy and presence our natural resources, for example, in the Delicate Arch in the Arches National Park. Probabilistic and statistical relationships were developed between the number of vehicles (N) at one time in the Wolfe Ranch parking lot and the number of visitors (X) at Delicate Arch 1.5 miles away in the Arches National Park, southeastern Utah. The value of N is determined such that 30 or more visitors are at the arch only 10% of the time.

Crovelli, R. A.

1997-01-01

138

Security and gain improvement of a practical quantum key distribution using a gated single-photon source and probabilistic photon-number resolution  

SciTech Connect

We propose a high security quantum key distribution (QKD) scheme utilizing one mode of spontaneous parametric downconversion gated by a photon number resolving detector. This photon number measurement is possible by using single-photon detectors operating at room temperature and optical fibers. By post selection, the multiphoton probability in this scheme can be reduced to lower than that of a scheme using an attenuated coherent light resulting in improvement of security. Furthermore, if distillation protocol (error correction and privacy amplification) is performed, the gain will be increased. Hence a QKD system with higher security and bit rate than the laser-based QKD system can be attained using present available technologies.

Horikiri, Tomoyuki; Sasaki, Hideki; Wang, Haibo; Kobayashi, Takayoshi [Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Corporation (JST) and Department of Physics, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033 (Japan)

2005-07-15

139

Atomic-vapor-based high efficiency optical detectors with photon number resolution.  

PubMed

The ability to detect very weak optical fields with high efficiency (>99%) and to distinguish the number of photons in a given time interval is a very challenging technical problem with enormous potential payoffs in quantum communications and information processing. We propose to employ an atomic vapor as the active medium, prepared in a specific quantum state using laser radiation. The absorption of a photon will be aided by a dressing laser, and the presence or absence of an excited atom will be detected using the "cycling transition" approach perfected for ion traps. By incorporating an appropriate up-conversion scheme, our method can be applied to a wide variety of optical wavelengths. PMID:12398600

James, Daniel F V; Kwiat, Paul G

2002-10-28

140

Counting fluorescent dye molecules on DNA origami by means of photon statistics.  

PubMed

Obtaining quantitative information about molecular assemblies with high spatial and temporal resolution is a challenging task in fluorescence microscopy. Single-molecule techniques build on the ability to count molecules one by one. Here, a method is presented that extends recent approaches to analyze the statistics of coincidently emitted photons to enable reliable counting of molecules in the range of 1-20. This method does not require photochemistry such as blinking or bleaching. DNA origami structures are labeled with up to 36 dye molecules as a new evaluation tool to characterize this counting by a photon statistics approach. Labeled DNA origami has a well-defined labeling stoichiometry and ensures equal brightness for all dyes incorporated. Bias and precision of the estimating algorithm are determined, along with the minimal acquisition time required for robust estimation. Complexes containing up to 18 molecules can be investigated non-invasively within 150 ms. The method might become a quantifying add-on for confocal microscopes and could be especially powerful in combination with STED/RESOLFT-type microscopy. PMID:23794455

Kurz, Anton; Schmied, Jürgen J; Grußmayer, Kristin S; Holzmeister, Phil; Tinnefeld, Philip; Herten, Dirk-Peter

2013-12-01

141

Quantum feedback by discrete quantum nondemolition measurements: Towards on-demand generation of photon-number states  

NASA Astrophysics Data System (ADS)

We propose a quantum feedback scheme for the preparation and protection of photon-number states of light trapped in a high- Q microwave cavity. A quantum nondemolition measurement of the cavity field provides information on the photon-number distribution. The feedback loop is closed by injecting into the cavity a coherent pulse adjusted to increase the probability of the target photon number. The efficiency and reliability of the closed-loop state stabilization is assessed by quantum Monte Carlo simulations. We show that, in realistic experimental conditions, the Fock states are efficiently produced and protected against decoherence.

Dotsenko, I.; Mirrahimi, M.; Brune, M.; Haroche, S.; Raimond, J.-M.; Rouchon, P.

2009-07-01

142

Thwarting the Photon Number Splitting Attack with Entanglement Enhanced BB84 Quantum Key Distribution  

NASA Astrophysics Data System (ADS)

We develop an improvement to the weak laser pulse BB84 scheme for quantum key distribution, which utilizes entanglement to improve the security of the scheme and enhance its resilience to the photon number splitting attack. This protocol relies on the non-commutation of photon phase and number to detect an eavesdropper performing quantum non-demolition measurement on number. The potential advantages and disadvantages of this scheme are compared to the coherent decoy state solution. Most entanglement based quantum key distribution schemes rely on violations of Bell's inequalities to ensure security. However, this is not the strategy that our entanglement enhanced (EE) BB84 employs here. Instead, we detect Eve by introducing an entangled quantum state into the system that is sensitive to Eve's QND measurements. This allows for a recovery of an approximately linear dependence on transmittivity for the key rate. EE BB84 shares this advantage with coherent decoy state protocols as well as schemes that utilize strong phase reference pulses to eliminate Eve's ability to send Bob vacuum signals.

Richardson, Chris; Sabottke, Carl; Yurtsever, Ulvi; Lamas, Antia; Dowling, Jonathan; Anisimov, Petr

2012-02-01

143

Conservation of the photon number in the generalized nonlinear Schroedinger equation in axially varying optical fibers  

SciTech Connect

We reexamine the derivation of the generalized nonlinear Schroedinger equation in the case of nonaxially uniform optical fibers, taking into account the longitudinal and spectral evolutions of all pertinent linear parameters. Our theory leads to an improved form of this equation that highlights an additional term, which ensures the conservation of the total photon number in nonuniform optical fibers in the absence of attenuation. Numerical simulations confirm the validity of this theory in the context of a Raman-induced soliton self-frequency shift, emission of Cherenkov radiation, and a soliton blue shift.

Vanvincq, O.; Travers, J. C.; Kudlinski, A. [Femtosecond Optics Group, Physics Department, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom); Universite Lille 1, Laboratoire PhLAM, IRCICA, F-59655 Villeneuve d'Ascq (France)

2011-12-15

144

Improved Statistical Analysis for Array CGH-Based DNA Copy Number Aberrations  

PubMed Central

Array-based comparative genomic hybridization (aCGH) allows measuring DNA copy number at the whole genome scale. In cancer studies, one may be interested in identifying DNA copy number aberrations (CNAs) associated with certain clinicopathological characteristics such as cancer metastasis. We proposed to define test regions based on copy number pattern profiles across multiple samples, using either smoothed log2-ratio or discrete data of copy number gain/loss calls. Association test performed on the refined test regions instead of the probes has improved power due to reduced number of tests. We also compared three types of measurement of copy number levels, normalized log2-ratio, smoothed log2-ratio, and copy number gain or loss calls in statistical hypothesis testing. The relative strengths and weaknesses of the proposed method were demonstrated using both simulation studies and real data analysis of a liver cancer study.

Jiang, Hongmei; Zhu, Zhong-Zheng; Yu, Yue; Lin, Simon; Hou, Lifang

2011-01-01

145

Statistical treatment of photon/electron counting: extending the linear dynamic range from the dark count rate to saturation.  

PubMed

An experimentally simple photon counting method is demonstrated providing 7 orders of magnitude in linear dynamic range (LDR) for a single photomultiplier tube (PMT) detector. In conventional photon/electron counting methods, the linear range is dictated by the agreement between the binomially distributed measurement of counted events and the underlying Poisson distribution of photons/electrons. By explicitly considering the log-normal probability distribution in voltage transients as a function of the number of photons present and the Poisson distribution of photons, observed counts for a given threshold can be related to the mean number of photons well beyond the conventional limit. Analytical expressions are derived relating counts and photons that extend the linear range to an average of ?11 photons arriving simultaneously with a single threshold. These expressions can be evaluated numerically for multiple thresholds extending the linear range to the saturation point of the PMT. The peak voltage distributions are experimentally shown to follow a Poisson weighted sum of log-normal distributions that can all be derived from the single photoelectron voltage peak-height distribution. The LDR that results from this method is compared to conventional single photon counting (SPC) and to signal averaging by analog to digital conversion (ADC). PMID:21114249

Kissick, David J; Muir, Ryan D; Simpson, Garth J

2010-12-15

146

An accurate simulation model for single-photon avalanche diodes including important statistical effects  

NASA Astrophysics Data System (ADS)

An accurate and complete circuit simulation model for single-photon avalanche diodes (SPADs) is presented. The derived model is not only able to simulate the static DC and dynamic AC behaviors of an SPAD operating in Geiger-mode, but also can emulate the second breakdown and the forward bias behaviors. In particular, it considers important statistical effects, such as dark-counting and after-pulsing phenomena. The developed model is implemented using the Verilog-A description language and can be directly performed in commercial simulators such as Cadence Spectre. The Spectre simulation results give a very good agreement with the experimental results reported in the open literature. This model shows a high simulation accuracy and very fast simulation rate.

Qiuyang, He; Yue, Xu; Feifei, Zhao

2013-10-01

147

Strong field line shapes and photon statistics from a single molecule under anomalous noise.  

PubMed

We revisit the line-shape theory of a single molecule with anomalous stochastic spectral diffusion. Waiting time profiles for bath induced spectral jumps in the ground and excited states become different when a molecule, probed by continuous-wave laser field, reaches the steady state. This effect is studied for the stationary dichotomic continuous-time-random-walk spectral diffusion of a single two-level chromophore with power-law distributions of waiting times. Correlated waiting time distributions, line shapes, two-point fluorescence correlation function, and Mandel Q parameter are calculated for arbitrary magnitude of laser field. We extended previous weak field results and examined the breakdown of the central limit theorem in photon statistics, indicated by asymptotic power-law growth of Mandel Q parameter. Frequency profile of the Mandel Q parameter identifies the peaks of spectrum, which are related to anomalous spectral diffusion dynamics. PMID:19905298

Sanda, Frantisek

2009-10-01

148

Fluorescence lifetimes and correlated photon statistics from single CdSe/oligo(phenylene vinylene) composite nanostructures.  

PubMed

We present measurements of fluorescence intensity trajectories and associated excited-state decay times from individual CdSe/oligo(phenylene vinylene) (CdSe-OPV) quantum dot nanostructures using time-tagged, time-resolved (TTTR) photon counting techniques. We find that fluorescence decay times for the quantum dot emitter in these composite systems are at least an order of magnitude shorter than ZnS-capped CdSe quantum dot systems. We show that both the blinking suppression and associated lifetime/count rate behavior can be described by a modified version of the diffusive reaction coordinate model which couples slow fluctuations in quantum dot electron (1Se, 1Pe) energies to Auger-assisted hole trapping processes, hence modifying both blinking statistics and excited-state decay rates. PMID:17655370

Odoi, M Y; Hammer, N I; Early, K T; McCarthy, K D; Tangirala, R; Emrick, T; Barnes, M D

2007-09-01

149

Statistical properties of online avatar numbers in a massive multiplayer online role-playing game  

NASA Astrophysics Data System (ADS)

Massive multiplayer online role-playing games (MMORPGs) have been very popular in the past few years. The profit of an MMORPG company is proportional to how many users registered, and the instant number of online avatars is a key factor to assess how popular an MMORPG is. We use the online-offline logs on an MMORPG server to reconstruct the instant number of online avatars per second and investigate its statistical properties. We find that the online avatar number exhibits one-day periodic behavior and clear intraday pattern, the fluctuation distribution of the online avatar numbers has a leptokurtic non-Gaussian shape with power-law tails, and the increments of online avatar numbers after removing the intraday pattern are uncorrelated and the associated absolute values have long-term correlation. In addition, both time series exhibit multifractal nature.

Jiang, Zhi-Qiang; Ren, Fei; Gu, Gao-Feng; Tan, Qun-Zhao; Zhou, Wei-Xing

2010-02-01

150

Measuring photon-photon interactions via photon detection  

SciTech Connect

Strong nonlinearity plays a significant role in physics, particularly in the design of novel quantum sources of light and matter as well as in quantum chemistry and quantum biology. In simple systems, the photon-photon interaction can be determined analytically. However, it becomes challenging to obtain it for more complex systems. Therefore, we show here how to measure strong nonlinearities by allowing the sample to interact with a weakly pumped quantized leaking optical mode. We found that the detected mean photon number versus pump-field frequency shows several peaks. Interestingly, the interval between neighboring peaks equals the photon-photon interaction potential. Furthermore, the system exhibits sub-Poissonian photon statistics, entanglement, and photon switching with less than one photon. Finally, we connect our study with existing experiments.

Macovei, Mihai A. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)

2010-12-15

151

Generating arbitrary photon-number entangled states for continuous-variable quantum informatics.  

PubMed

We propose two experimental schemes that can produce an arbitrary photon-number entangled state (PNES) in a finite dimension. This class of entangled states naturally includes non-Gaussian continuous-variable (CV) states that may provide some practical advantages over the Gaussian counterparts (two-mode squeezed states). We particularly compare the entanglement characteristics of the Gaussian and the non-Gaussian states in view of the degree of entanglement and the Einstein-Podolsky-Rosen correlation, and further discuss their applications to the CV teleportation and the nonlocality test. The experimental imperfection due to the on-off photodetectors with nonideal efficiency is also considered in our analysis to show the feasibility of our schemes within existing technologies. PMID:22714485

Lee, Su-Yong; Park, Jiyong; Lee, Hai-Woong; Nha, Hyunchul

2012-06-18

152

Quantum state of an injected TROPO above threshold: purity, Glauber function and photon number distribution  

NASA Astrophysics Data System (ADS)

In this paper, we investigate several properties of the full signal-idler-pump mode quantum state generated by a triply resonant non-degenerate Optical Parametric Oscillator operating above threshold, with an injected wave on the signal and idler modes in order to lock the phase diffusion process. We determine and discuss the spectral purity of this state, which turns out not to be always equal to 1 even though the three interacting modes have been taken into account at the quantum level. We have seen that the purity is essentially dependent on the weak intensity of the injected light and on an asymmetry of the synchronization. We then derive the expression of its total three-mode Glauber P-function, and calculate the joint signal-idler photon number probability distribution and investigate their dependence on the injection.

Golubeva, T.; Golubev, Yu.; Fabre, C.; Treps, N.

2008-01-01

153

Photon-number splitting of squeezed light by a single qubit in circuit QED  

NASA Astrophysics Data System (ADS)

We theoretically propose an efficient way to generate and detect squeezed light by a single qubit in circuit QED. By tuning the qubit energy splitting close to the fundamental frequency of the first harmonic mode (FHM) in a transmission line resonator and placing the qubit at the nodal point of the third harmonic mode, one can generate the resonantly enhanced squeezing of the FHM upon pumping with the second harmonic mode. In order to investigate the photon number splitting for the squeezed FHM, we have numerically calculated the qubit absorption spectrum, which exhibits regularly spaced peaks at frequencies separated by twice the effective dispersive shift. It is also shown that adding a small pump field for the FHM makes additional peaks develop in between the dominant ones as well.

Moon, Kyungsun

2013-10-01

154

Statistics of scattered photons from a driven three-level emitter in a one-dimensional open space  

NASA Astrophysics Data System (ADS)

We derive the statistics of scattered photons from a ?- or ladder-type three-level emitter (3LE) embedded in a one-dimensional open waveguide. The weak probe photons in the waveguide are coupled to one of the two allowed transitions of the 3LE, and the other transition is driven by a control beam. This system shows electromagnetically induced transparency, which is accompanied with the Autler-Townes splitting (ATS) at a strong driving by the control beam, and some of these effects have been observed recently. We show that the nature of second-order coherence of the transmitted probe photons near two-photon resonance changes from bunching to antibunching to constant as the strength of the control beam is ramped up from zero to a higher value where the ATS appears.

Roy, Dibyendu; Bondyopadhaya, Nilanjan

2014-04-01

155

High-statistics study of K0S pair production in two-photon collisions  

NASA Astrophysics Data System (ADS)

We report a high-statistics measurement of the differential cross section of the process ? ? to K^0_S K^0_S in the range 1.05 {GeV} ? W ? 4.00 GeV, where W is the center-of-mass energy of the colliding photons, using 972 fb^{-1} of data collected with the Belle detector at the KEKB asymmetric-energy e^+ e^- collider operated at and near the Upsilon -resonance region. The differential cross section is fitted by parameterized S-, D_0-, D_2-, G_0-, and G_2-wave amplitudes. In the D_2 wave, the f_2(1270), a_2(1320), and f_2'(1525) are dominant and a resonance, the f_2(2200), is also present. The f_0(1710) and possibly the f_0(2500) are seen in the S wave. The mass, total width, and product of the two-photon partial decay width and decay branching fraction to the K bar {K} state ? _{? ? }mathcal {B}(K bar {K}) are extracted for the f_2'(1525), f_0(1710), f_2(2200), and f_0(2500). The destructive interference between the f_2(1270) and a_2(1320) is confirmed by measuring their relative phase. The parameters of the charmonium states ? _{c0} and ? _{c2} are updated. Possible contributions from the ? _{c0}(2P) and ? _{c2}(2P) states are discussed. A new upper limit for the branching fraction of the P- and CP-violating decay channel ? _c to K^0_S K^0_S is reported. The detailed behavior of the cross section is updated and compared with QCD-based calculations.

Uehara, S.; Watanabe, Y.; Nakazawa, H.; Adachi, I.; Aihara, H.; Asner, D. M.; Aulchenko, V.; Aushev, T.; Bakich, A. M.; Bala, A.; Bhardwaj, V.; Bhuyan, B.; Bondar, A.; Bonvicini, G.; Bozek, A.; Bra?ko, M.; Chekelian, V.; Chen, A.; Chen, P.; Cheon, B. G.; Chilikin, K.; Chistov, R.; Cho, K.; Chobanova, V.; Choi, S.-K.; Choi, Y.; Cinabro, D.; Dalseno, J.; Dingfelder, J.; Doležal, Z.; Dutta, D.; Eidelman, S.; Epifanov, D.; Farhat, H.; Fast, J. E.; Feindt, M.; Ferber, T.; Frey, A.; Gaur, V.; Gabyshev, N.; Ganguly, S.; Gillard, R.; Giordano, F.; Goh, Y. M.; Golob, B.; Haba, J.; Hayasaka, K.; Hayashii, H.; Hoshi, Y.; Hou, W.-S.; Hyun, H. J.; Iijima, T.; Ishikawa, A.; Itoh, R.; Iwasaki, Y.; Julius, T.; Kah, D. H.; Kang, J. H.; Kato, E.; Kawai, H.; Kawasaki, T.; Kiesling, C.; Kim, D. Y.; Kim, H. O.; Kim, J. B.; Kim, J. H.; Kim, Y. J.; Klucar, J.; Ko, B. R.; Kodyš, P.; Korpar, S.; Križan, P.; Krokovny, P.; Kumita, T.; Kuzmin, A.; Kwon, Y.-J.; Lee, S.-H.; Li, J.; Li, Y.; Liu, C.; Liu, Z. Q.; Liventsev, D.; Lukin, P.; Matvienko, D.; Miyabayashi, K.; Miyata, H.; Mizuk, R.; Moll, A.; Mori, T.; Muramatsu, N.; Mussa, R.; Nagasaka, Y.; Nakao, M.; Ng, C.; Nisar, K. N.; Nishida, S.; Nitoh, O.; Ogawa, S.; Okuno, S.; Pakhlova, G.; Park, C. W.; Park, H.; Park, H. K.; Pedlar, T. K.; Pestotnik, R.; Petri?, M.; Piilonen, L. E.; Ritter, M.; Röhrken, M.; Rostomyan, A.; Sahoo, H.; Saito, T.; Sakai, Y.; Sandilya, S.; Santelj, L.; Sanuki, T.; Savinov, V.; Schneider, O.; Schnell, G.; Schwanda, C.; Seidl, R.; Senyo, K.; Seon, O.; Shapkin, M.; Shen, C. P.; Shibata, T.-A.; Shiu, J.-G.; Shwartz, B.; Sibidanov, A.; Simon, F.; Sohn, Y.-S.; Sokolov, A.; Solovieva, E.; Stari?, M.; Steder, M.; Sumihama, M.; Sumiyoshi, T.; Tamponi, U.; Tanida, K.; Tatishvili, G.; Teramoto, Y.; Uchida, M.; Uglov, T.; Unno, Y.; Uno, S.; Urquijo, P.; Vahsen, S. E.; Van Hulse, C.; Varner, G.; Wagner, M. N.; Wang, C. H.; Wang, M.-Z.; Wang, P.; Wang, X. L.; Williams, K. M.; Won, E.; Yamashita, Y.; Yashchenko, S.; Yook, Y.; Yuan, C. Z.; Yusa, Y.; Zhang, C. C.; Zhang, Z. P.; Zhilich, V.; Zhulanov, V.; Zupanc, A.

2013-12-01

156

Evaluation of polarization entanglement generated by spontaneous parametric downconversion using photon number counting  

Microsoft Academic Search

Spontaneous parametric downconversion (SPDC) is widely used to generate entangled photon pairs; however, multi-pair emissions degrade the quality of the entanglement. We numerically evaluate polarization-entangled photon pairs created by SPDC. The effects of multi-pair emission events on the visibility of two-photon interference and on the fidelity (the probability overlap for ideal and real states) are analyzed using single-photon detectors that

A. Yoshizawa; D. Fukuda; H. Tsuchida

157

Number-Between g Type Statistical Quality Control Charts for Monitoring Adverse Events  

Microsoft Academic Search

Alternate Shewhart-type statistical control charts, called “g” and “h” charts, are developed and evaluated for monitoring the number of cases between hospital-acquired infections and other adverse events, such as heart surgery complications, catheter-related infections, surgical site infections, contaminated needle sticks, and other iatrically induced outcomes. These new charts, based on inverse sampling from geometric and negative binomial distributions, are simple

James C. Benneyan

2001-01-01

158

Use of statistical methods for estimation of total number of charges in a mass spectrometry experiment.  

PubMed

Estimation of the number of ions in a mass spectrometry experiment is needed to determine instrumentation parameters such as ionization efficiency, collision-induced dissociation efficiency, ion-transfer efficiency, ion trapping efficiency, and preamplifier detection limit. This work aims at analyzing the statistical characteristics (primarily variance) in the intensities of the isotopic distributions, which depend on the number of ions in the cell. A mathematical derivation was developed based on the maximum likelihood estimation method, which estimates the most likely number of ions in the cell using a method known as nonrandom parameter estimation. The performance of the method improves with increase in the number of observed distributions. The method works well provided the spectra show isotopic resolution and is independent of the instrument or method used to arrive at the spectra. PMID:15144185

Kaur, Parminder; O'Connor, Peter B

2004-05-15

159

An ultrafast quantum random number generator with provably bounded output bias based on photon arrival time measurements  

NASA Astrophysics Data System (ADS)

We report the implementation of a quantum random number generator based on photon arrival times. Due to fast and high resolution timing we are able to generate the highest bitrate of any current generator based on photon arrival times. Bias in the raw data due to the exponential distribution of the arrival times is removed by postprocessing which is directly integrated in the field programmable logic of the timing electronics.

Wahl, Michael; Leifgen, Matthias; Berlin, Michael; Röhlicke, Tino; Rahn, Hans-Jürgen; Benson, Oliver

2011-04-01

160

RE-EXAMINATION OF THE STATISTICAL METHODS USED TO DETERMINE THE NUMBER OF POINT COUNTS NEEDED FOR MICROPALEONTOLOGICAL QUANTITATIVE RESEARCH  

Microsoft Academic Search

Currently some controversy exists in the micropaleontological community concerning the statistically correct number of counts required for quantitative examinations, particularly with respect to the effect of variations in the number ofspedes between samples and the significance of varying fractional abundances on the reliability of results, This analysis of the various statistical methods used to determine the number of required counts

R. TIMOTHY PATTERSON; EVAN FISHBEIN

1989-01-01

161

Quantum fingerprinting with coherent states and a constant mean number of photons  

NASA Astrophysics Data System (ADS)

We present a protocol for quantum fingerprinting that is ready to be implemented with current technology and is robust to experimental errors. The basis of our scheme is an implementation of the signal states in terms of a coherent state in a superposition of time-bin modes. Experimentally, this requires only the ability to prepare coherent states of low amplitude and to interfere them in a balanced beam splitter. The states used in the protocol are arbitrarily close in trace distance to states of O (log2n) qubits, thus exhibiting an exponential separation in abstract communication complexity compared to the classical case. The protocol uses a number of optical modes that is proportional to the size n of the input bit strings but a total mean photon number that is constant and independent of n. Given the expended resources, our protocol achieves a task that is provably impossible using classical communication only. In fact, even in the presence of realistic experimental errors and loss, we show that there exist a large range of input sizes for which our quantum protocol transmits an amount of information that can be more than two orders of magnitude smaller than a classical fingerprinting protocol.

Arrazola, Juan Miguel; Lütkenhaus, Norbert

2014-06-01

162

Streamwise velocity statistics in turbulent boundary layers that spatially develop to high Reynolds number  

NASA Astrophysics Data System (ADS)

Well-resolved measurements of the streamwise velocity in zero pressure gradient turbulent boundary layers are presented for friction Reynolds numbers up to 19,670. Distinct from most studies, the present boundary layers undergo nearly a decade increase in Reynolds number solely owing to streamwise development. The profiles of the mean and variance of the streamwise velocity exhibit logarithmic behavior in accord with other recently reported findings at high Reynolds number. The inner and mid-layer peaks of the variance profile are evidenced to increase at different rates with increasing Reynolds number. A number of statistical features are shown to correlate with the position where the viscous force in the mean momentum equation loses leading order importance, or similarly, where the mean effect of turbulent inertia changes sign from positive to negative. The near-wall peak region in the 2-D spectrogram of the fluctuations is captured down to wall-normal positions near the edge of the viscous sublayer at all Reynolds numbers. The spatial extent of this near-wall peak region is approximately invariant under inner normalization, while its large wavelength portion is seen to increase in scale in accord with the position of the mid-layer peak, which resides at a streamwise wavelength that scales with the boundary layer thickness.

Vincenti, P.; Klewicki, J.; Morrill-Winter, C.; White, C. M.; Wosnik, M.

2013-12-01

163

Mean velocity statistics and turbulent structure in a very high Reynolds number boundary layer  

NASA Astrophysics Data System (ADS)

PIV measurements were acquired over a region of y+ up to 3000 in the atmospheric surface layer at the SLTEST site with a range of 6000 wall units in the streamwise direction. The surface roughness was k+=14, with a boundary layer thickness of order 100m. The thermal conditions were neutral for more than one hour prior to and after the measurement period. A total of 708 snapshots were acquired in a 25 minute period where the wind conditions were nearly stationary. In this talk, mean velocity statistics will be used in comparison to the log-law fit as well as a power law fit. RMS statistics and Reynolds stresses will be compared with lower Reynolds number data. Finally, the structure of the flow will be described both in terms of stochastic quantities, such as the two point correlation functions, as well as instantaneous visualizations of the vector field.

Morris, Scott

2005-11-01

164

Photon-number squeezing with a noisy femtosecond fiber laser amplifier source using a collinear balanced detection technique.  

PubMed

We experimentally demonstrate photon-number squeezing at 1.55 ?m using a noisy erbium-doped fiber amplifier (EDFA). We employ a collinear balanced detection (CBD) technique, where the intensity noise at a specific radio frequency is canceled between two pulse trains. In spite of substantially large excess noise (>10 dB) in an EDFA due to amplified spontaneous emission, we successfully cancel the intensity noise and achieve a shot noise limit at a specific radio frequency with the CBD technique. We exploit two sets of fiber polarization interferometers to generate squeezed light and observe a maximal photon-number squeezing of -2.6 dB. PMID:24150352

Sawai, Shota; Kawauchi, Hikaru; Hirosawa, Kenichi; Kannari, Fumihiko

2013-10-21

165

Evaluating statistical methods used to estimate the number of postsynaptic receptors  

PubMed Central

Calcium levels in spines play a significant role in determining the sign and magnitude of synaptic plasticity [Yang et al., 1999, Malenka and Bear, 2001, Cummings et al., 1996]. The magnitude of calcium influx into spines is highly dependent on influx through N-methyl D-aspartate (NMDA) receptors [Sabatini et al., 2002], and therefore depends on the number of postsynaptic NMDA receptors in each spine. We have calculated previously how the number of postsynaptic NMDA receptors determines the mean and variance of calcium transients in the postsynaptic density [Yeung et al., 2004], and how this alters the shape of plasticity curves [Shouval and Kalantzis, 2005]. However, the number of postsynaptic NMDA receptors in the postsynaptic density is not well known. Anatomical methods for estimating the number of NMDA receptors [Takumi et al., 1999, Racca et al., 2000] produce estimates that are very different than those produced by physiological techniques[Nimchinsky et al., 2004]. The physiological techniques are based on the statistics of synaptic transmission and it is difficult to experimentally estimate their precision. In this paper we use stochastic simulations in order to test the validity of a physiological estimation technique based on failure analysis. We find that the method is likely to underestimate the number of postsynaptic NMDA receptors, explain the source of the error, and re-derive a more precise estimation technique. We also show that the original failure analysis as well as our improved formulas are not robust to small estimation errors in key parameters.

Kalantzis, Georgios; Kubota, Yoshira; Shouval, Harel Z.

2009-01-01

166

Statistics of the cosmic Mach number from numerical simulations of a cold dark matter universe  

NASA Technical Reports Server (NTRS)

Results are presented of an analysis of the cosmic Mach number, M, the ratio of the streaming velocity, v, to the random velocity dispersion, sigma, of galaxies in a given patch of the universe, which was performed on the basis of hydrodynamical simulations of the cold dark matter scenario. Galaxy formation is modeled by application of detailed physical processes rather than by the ad hoc assumption of 'bias' between dark matter and galaxy fluctuations. The correlation between M and sigma is found to be very weak for both components. No evidence is found for a physical 'velocity bias' in the quantities which appear in the definition of M. Standard cold-dark-matter-dominated universes are in conflict, at a statistically significant level, with the available observation, in that they predict a Mach number considerably lower than is observed.

Suto, Yasushi; Cen, Renyue; Ostriker, Jeremiah P.

1992-01-01

167

Finite-size fluctuations and photon statistics near the polariton condensation transition in a single-mode microcavity  

SciTech Connect

We consider polariton condensation in a generalized Dicke model, describing a single-mode cavity containing quantum dots, and extend our previous mean-field theory to allow for finite-size fluctuations. Within the fluctuation-dominated regime the correlation functions differ from their (trivial) mean-field values. We argue that the low-energy physics of the model, which determines the photon statistics in this fluctuation-dominated crossover regime, is that of the (quantum) anharmonic oscillator. The photon statistics at the crossover are different in the high-temperature and low-temperature limits. When the temperature is high enough for quantum effects to be neglected we recover behavior similar to that of a conventional laser. At low enough temperatures, however, we find qualitatively different behavior due to quantum effects.

Eastham, P. R.; Littlewood, P. B. [Theory of Condensed Matter Group, Cavendish Laboratory, Madingley Road, Cambridge CB3 0HE (United Kingdom)

2006-02-15

168

Relation between shear parameter and Reynolds number in statistically stationary turbulent shear flows  

NASA Astrophysics Data System (ADS)

Studies of the relation between the shear parameter S* and the Reynolds number Re are presented for a nearly homogeneous and statistically stationary turbulent shear flow. The parametric investigations are in line with a generalized perspective on the return to local isotropy in shear flows that was outlined recently [J. Schumacher, K. R. Sreenivasan, and P. K. Yeung, Phys. Fluids 15, 84 (2003)]. Therefore, two parameters, the constant shear rate S and the level of initial turbulent fluctuations as prescribed by an energy injection rate ?in, are varied systematically. The investigations suggest that the shear parameter levels off for larger Reynolds numbers which is supported by dimensional arguments. It is found that the skewness of the transverse derivative shows a different decay behavior with respect to Reynolds number when the sequence of simulation runs follows different pathways across the two-parameter plane. The study can shed new light on different interpretations of the decay of odd order moments in high-Reynolds number experiments.

Schumacher, Jörg

2004-08-01

169

Publications from the National Center for Health Statistics Statistics Volume 1, Number 2, November 1996 (on CD-ROM).  

National Technical Information Service (NTIS)

Product contains the full text of Health, United States, 1995 and other recent publications of the National Center for Health Statistics (NCHS). These publications can be viewed, searched, printed, and downloaded using the Adobe Acrobat LE software on the...

1996-01-01

170

Statistical structure of turbulent-boundary-layer velocity vorticity products at high and low Reynolds numbers  

NASA Astrophysics Data System (ADS)

The mean wall-normal gradients of the Reynolds shear stress and the turbulent kinetic energy have direct connections to the transport mechanisms of turbulent-boundary-layer flow. According to the Stokes Helmholtz decomposition, these gradients can be expressed in terms of velocity vorticity products. Physical experiments were conducted to explore the statistical properties of some of the relevant velocity vorticity products. The high-Reynolds-number data (R_{theta} {?} O(10(6)) , where theta is the momentum thickness) were acquired in the near neutrally stable atmospheric-surface-layer flow over a salt playa under both smooth- and rough-wall conditions. The low-R_{theta} data were from a database acquired in a large-scale laboratory facility at 1000{<} R_{theta} {<} 5000. Corresponding to a companion study of the Reynolds stresses (Priyadarshana & Klewicki, Phys. Fluids, vol. 16, 2004, p. 4586), comparisons of low- and high-R_{theta} as well as smooth- and rough-wall boundary-layer results were made at the approximate wall-normal locations y_p/2 and 2y_p, where y_p is the wall-normal location of the peak of the Reynolds shear stress, at each Reynolds number. In this paper, the properties of the vomega_z, womega_y and uomega_z products are analysed through their statistics and cospectra over a three-decade variation in Reynolds number. Here u, v and w are the fluctuating streamwise, wall-normal and spanwise velocity components and omega_y and omega_z are the fluctuating wall-normal and spanwise vorticity components. It is observed that v omega_z statistics and spectral behaviours exhibit considerable sensitivity to Reynolds number as well as to wall roughness. More broadly, the correlations between the {bm v} and {bm omega} fields are seen to arise from a ‘scale selection’ near the peak in the associated vorticity spectra and, in some cases, near the peak in the associated velocity spectra as well.

Priyadarshana, P. J. A.; Klewicki, J. C.; Treat, S.; Foss, J. F.

171

Health Technology Assessment Reports 1986. Number 6. Dual Photon Absorptiometry for Measuring Bone Mineral Density.  

National Technical Information Service (NTIS)

Dual photon absorptiometry (DPA) is a noninvasive radiologic technique used to measure bone mineral density (BMD) in the lumbar spine and hip. With DPA the amount of bone mineral measured represents the total integrated mineral (cortical and trabecular) i...

M. Erlichman

1986-01-01

172

Full counting statistics for the number of electrons in a quantum dot  

NASA Astrophysics Data System (ADS)

Motivated by recent real-time electron counting experiments, we evaluate the full counting statistics for the probability distribution of the electron number inside a quantum dot which is weakly coupled to source and drain leads. A non-Gaussian exponential distribution appears when there is no dot state close to the lead chemical potentials. We propose the measurement of the joint probability distribution of current and electron number, which reveals correlations between the two observables. We also show that for increasing strength of tunneling, the quantum fluctuations qualitatively change the probability distribution of the electron number. In this paper, we derive the cumulant generating functions (CGFs) of the joint probability distribution for several cases. The Keldysh generating functional approach is adopted to obtain the CGFs for the resonant-level model and for the single-electron transistor in the intermediate conductance regime. The general form for the CGF of the joint probability distribution is provided within the Markov approximation in an extension of the master equation approach [D. A. Bagrets and Yu. V. Nazarov, Phys. Rev. B 67, 085316 (2003)].

Utsumi, Yasuhiro

2007-01-01

173

Statistical anisotropy in free turbulence for mixing layers at high Reynolds numbers.  

PubMed

A lateral shearing interferometer was used to measure the slope of perturbed wave fronts after propagating through free turbulent mixing layers. Shearing interferometers provide a two-dimensional flow visualization that is nonintrusive. Slope measurements were used to reconstruct the phase of the turbulence-corrupted wave front. The random phase fluctuations induced by the mixing layer were captured in a large ensemble of wave-front measurements. Experiments were performed on an unbounded, plane shear mixing layer of helium and nitrogen gas at fixed velocities and high Reynolds numbers for six locations in the flow development. Statistical autocorrelation functions and structure functions were computed on the reconstructed phase maps. The autocorrelation function results indicated that the turbulence-induced phase fluctuations were not wide-sense stationary. The structure functions exhibited statistical homogeneity, indicating that the phase fluctuations were stationary in first increments. However, the turbulence-corrupted phase was not isotropic. A five-thirds power law is shown to fit orthogonal slices of the structure function, analogous to the Kolmogorov model for isotropic turbulence. Strehl ratios were computed from the phase structure functions and compared with classical estimates that assume isotropy. The isotropic models are shown to overestimate the optical degradation by nearly 3 orders of magnitude compared with the structure function calculations. PMID:21102914

Gardner, P J; Roggemann, M C; Welsh, B M; Bowersox, R D; Luke, T E

1996-08-20

174

Photons  

NSDL National Science Digital Library

In this activity using an open space and a thick rope, students simulate the movement of photons from the Sun. The resource is part of the teacher's guide accompanying the video, NASA Why Files: The Case of the Mysterious Red Light. Lesson objectives supported by the video, additional resources, teaching tips and an answer sheet are included in the teacher's guide.

175

Quantum receivers with squeezing and photon-number-resolving detectors for M-ary coherent state discrimination  

NASA Astrophysics Data System (ADS)

We propose quantum receivers with optical squeezing and photon-number-resolving detectors (PNRDs) for the near-optimal discrimination of quaternary phase-shift-keyed coherent state signals. The basic scheme is similar to the previous proposals [e.g., Izumi , Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.86.042328 86, 042328 (2012)] in which displacement operations, on-off detectors, and electrical feedforward operations were used. Here we study two types of receivers, one of which installs optical squeezings and the other uses PNRDs instead of on-off detectors. We show that both receivers can attain lower error rates than that in the previous scheme. In particular, we show the PNRD-based receiver has a significant gain when the ratio between the mean photon number of the signal and the number of the feedforward steps is relatively high, in other words, when the probability of detecting two or more photons at each detector is not negligible. Moreover, we show that the PNRD-based receiver can suppress the errors due to dark counts, which the receiver with the on-off detector cannot do with a small number of feedforwards.

Izumi, Shuro; Takeoka, Masahiro; Ema, Kazuhiro; Sasaki, Masahide

2013-04-01

176

Proof-of-principle experiment of a modified photon-number-splitting attack against quantum key distribution  

SciTech Connect

Any imperfections in a practical quantum key distribution (QKD) system may be exploited by an eavesdropper to collect information about the key without being discovered. We propose a modified photon-number-splitting attack scheme against QKD systems based on weak laser pulses taking advantage of possible multiphoton pulses. Proof-of-principle experiments are demonstrated. The results show that the eavesdropper can get information about the key generated between the legitimate parties without being detected. Since the equivalent attenuation introduced by the eavesdropper for pulses of different average photon numbers are different, the decoy-state method is effective in fighting against this kind of attack. This has also been proven in our experiments.

Liu Weitao; Sun Shihai; Liang Linmei; Yuan Jianmin [Department of Physics, College of Science, National University of Defense Technology, Changsha, 410073 (China)

2011-04-15

177

Losing Count: The Federal Statistical System. Population Trends and Public Policy Occasional Paper Number 16.  

ERIC Educational Resources Information Center

The main responsibility of the U.S. Bureau of the Census, Bureau of Labor Statistics, and the National Centers for Health and Education Statistics is to collect, process, analyze, and disseminate statistical data on the economic, physical, and social characteristics of the United States. Under the Paperwork Reduction Act of 1980, the federal…

Wallman, Katherine K.

178

The statistical single-photon technique in physical-optic experiments  

Microsoft Academic Search

The principles underlying the time-correlated single-photon technique are discussed. An analysis is then presented of the characteristic errors of this technique for various experimental conditions, differing in regard to the character and type of input fluxes and their intensities. Particular attention is given to the application of this technique in the stochastic excitation of radio luminescence. Ways to enhance the

M. I. Demchuk; M. A. Ivanov

1981-01-01

179

Statistical properties of coherent photon-subtracted two-mode squeezed vacuum and its application in quantum teleportation  

NASA Astrophysics Data System (ADS)

We introduce a kind of non-Gaussian entangled state, which can be obtained by operating a non-local coherent photon-subtraction operation on a two-mode squeezed vacuum. It is found that its normalization factor is only related to the Legendre polynomials, which is a compact expression. Its statistical properties are discussed by the negative region Wigner function with the analytical expression. As an application, the quantum teleportation for coherent states is considered by using the non-Gaussian state as an entangled channel. It is found that the teleportation fidelity can be enhanced by this non-Gaussian operation.

Zhang, Guo-Ping; Zheng, Kai-Min; Liu, Shi-You; Hu, Li-Yun

2014-05-01

180

Numbers of scintillation photons produced in NaI(Tl) and plastic scintillator by gamma-rays  

Microsoft Academic Search

The WS-value, which is defined as an average energy expended per scintillation photon, is determined to be 17.2±0.40 eV for a NaI(Tl) phosphor and 60.8±4.3 eV for a plastic scintillator (NE-102A). These are obtained from the numbers of photoelectrons measured with several combinations of a photomultiplier tube and a NaI(Tl) or a NE-102A scintillator. The number of photoelectrons, which are

M. Miyajima; S. Sasaki; H. Tawara

1993-01-01

181

Performance of photon-number resolving transition-edge sensors with integrated 1550 nm resonant cavities  

Microsoft Academic Search

Many quantum-information applications require high-efficiency, low-noise, single-photon detectors that operate at visible and near-infrared wavelengths. The tunable superconducting critical temperature and anomalously low electron-phonon coupling of tungsten make it a suitable material for the fabrication of transition-edge sensors (TESs) that meet these requirements. The quantum efficiency of a typical tungsten TES detector, intrinsically around 15% at 1550 nm, can be

D. Rosenberg; A. E. Lita; A. J. Miller; S. Nam; R. E. Schwall

2005-01-01

182

Emission properties and photon statistics of a single quantum dot laser.  

PubMed

A theoretical description for a single quantum-dot emitter in a microcavity is developed.We analyze for increasing steady-state pump rate the transition from the strong-coupling regime with photon antibunching to the weak-coupling regime with coherent emission. It is demonstrated how Coulomb interaction of excited carriers and excitation-induced dephasing can strongly modify the emission properties. Our theoretical investigations are based on a direct solution of the Liouville-von Neumann equation for the coupled carrier-photon system. We include multiple carrier excitations in the quantum dot, their Coulomb interaction, as well as excitation-induced dephasing and screening. Similarities and differences to atomic systems are discussed and results in the regime of recent experiments are interpreted. PMID:20588843

Ritter, S; Gartner, P; Gies, C; Jahnke, F

2010-05-10

183

Wavelength-selected photon-number-splitting attack against plug-and-play quantum key distribution systems with decoy states  

NASA Astrophysics Data System (ADS)

Any imperfections in a practical quantum key distribution (QKD) system may be exploited by an eavesdropper (Eve) to collect information about the key without being discovered. For example, without the decoy-state method, Eve can perform the photon-number-splitting (PNS) attack and get full information without introducing any perturbation, since weak laser pulses are widely used in practical systems instead of single-photon sources. However, the decoy-state method against PNS attack itself may introduce another loophole while closing the loophole of multiphoton pulses. In this paper, a fatal loophole of practical decoy-state plug-and-play QKD systems has been exploited and a wavelength-selected photon-number-splitting (WSPNS) attack scheme against plug-and-play QKD systems with the decoy-state method is proposed. Theoretical analysis shows that the eavesdropper can get full information about the key generated between the legitimate parties just like the PNS attack was performed in plug-and-play QKD systems without the decoy-state method.

Jiang, Mu-Sheng; Sun, Shi-Hai; Li, Chun-Yan; Liang, Lin-Mei

2012-09-01

184

Evolution Law of the Negative Binomial State in Laser Channel and its Photon-Number Decay Formula  

NASA Astrophysics Data System (ADS)

For the first time we examine how a negative binomial state (NBS), whose density operator is {sum }_{n=0}^{infty } {(n+s) !}/{n!s!}? ^{s+1}(1-? )n\\vert nrangle left < n\\vert , evolves in a laser channel. By using a newly derived generating function formula about Laguerre polynomial we obtain the evolution law of NBS, which turns out to be an infinite operator-sum of photon-added negative binomial state with a new negative-binomial parameter, and the photon number of NBS decays with e -2(?-g)t , where g and ? represent the cavity gain and loss respectively. The technique of integration (summation) within an ordered product of operators is used in our discussions.

Da, Cheng; Chen, Qian-Fan; Fan, Hong-Yi

2014-06-01

185

Advance Data from Vital and Health Statistics: Numbers 11-120.  

National Technical Information Service (NTIS)

Data in this report from health and demographic surveys present statistics by age and other variables on pregnant workers; ambulatory medical care; weight and height; episodes of persons injured; and exercise and sports participation. Estimates are based ...

1989-01-01

186

Photon statistics in blinking fluorescence of single PPV-PPyV molecule.  

PubMed

A theoretical six-level model for blinking fluorescence of single PPV-PPyV copolymer molecule excited by CW-laser light is proposed. The model has been chosen in accordance with the following facts found in the Paul Barbara group experiment: (i) alternation of two types of fluorescence with moderate and strong levels of emission, (ii) existence of "dark" states with no fluorescence, (iii) linear dependence of inverse on-interval duration on laser intensity, and (iv) existence of laser intensity independent off-intervals. Relations between the distribution function w''(N, T) for photons emitted by a single molecule, the distribution function w'(N, T) for photons arriving at photomultiplier tube (PMT) and photo-electric pulse distribution w(N, T) created in a PMT are discussed. The theory is able to describe pulse distribution function w(N, T) measured experimentally at signal acquisition time T = 0.1 s. Values of all rate constants of the model have been found from comparison of the theory with the experiment. Distributions w(on, off)(t) of on- and off-times and distribution w(N, T) of pulses have been calculated for infrequent and frequent inter-conformational jumps in single copolymer molecule. PMID:21974562

Fedyanin, V V; Osad'ko, I S

2011-09-28

187

Quantifying the number of color centers in single fluorescent nanodiamonds by photon correlation spectroscopy and Monte Carlo simulation  

SciTech Connect

The number of negatively charged nitrogen-vacancy centers (N-V){sup -} in fluorescent nanodiamond (FND) has been determined by photon correlation spectroscopy and Monte Carlo simulations at the single particle level. By taking account of the random dipole orientation of the multiple (N-V){sup -} fluorophores and simulating the probability distribution of their effective numbers (N{sub e}), we found that the actual number (N{sub a}) of the fluorophores is in linear correlation with N{sub e}, with correction factors of 1.8 and 1.2 in measurements using linearly and circularly polarized lights, respectively. We determined N{sub a}=8{+-}1 for 28 nm FND particles prepared by 3 MeV proton irradiation.

Hui, Y.Y.; Chang, Y.-R.; Lee, H.-Y.; Chang, H.-C. [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan (China); Lim, T.-S. [Department of Physics, Tunghai University, Taichung 407, Taiwan (China); Fann Wunshain [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan (China); Department of Physics, National Taiwan University, Taipei 106, Taiwan (China)

2009-01-05

188

Generic two-qubit photonic gates implemented by number-resolving photodetection  

SciTech Connect

We combine numerical optimization techniques [Uskov et al., Phys. Rev. A 79, 042326 (2009)] with symmetries of the Weyl chamber to obtain optimal implementations of generic linear-optical Knill-Laflamme-Milburn-type two-qubit entangling gates. We find that while any two-qubit controlled-U gate, including controlled-NOT (CNOT) and controlled-sign gates, can be implemented using only two ancilla resources with a success probability S>0.05, a generic SU(4) operation requires three unentangled ancilla photons, with success S>0.0063. Specifically, we obtain a maximal success probability close to 0.0072 for the B gate. We show that single-shot implementation of a generic SU(4) gate offers more than an order of magnitude increase in the success probability and a two-fold reduction in overhead ancilla resources compared to standard triple-CNOT and double-B gate decompositions.

Uskov, Dmitry B.; Smith, A. Matthew; Kaplan, Lev [Department of Physics, Tulane University, New Orleans, Louisiana 70118 (United States)

2010-01-15

189

Numbers  

NSDL National Science Digital Library

This engaging web site contains information and interactive applets related to various number systems: Egyptian, Babylonian, Chinese, Greek, Roman, Mayan, and Arabic. Users learn the history and structure of each system as well as how to count and write numbers. The site also allows users to explore finger systems, calculating machines, other number bases, and "interesting numbers." A series of pages on data and graphs includes information and activities on gathering, analyzing, graphing and sorting data. (Because the section on the Arabic number system is so extensive, it is cataloged separately as a related resource.)

Edkins, Jo

2006-01-01

190

A Statistical Change Point Model Approach for the Detection of DNA Copy Number Variations in Array CGH Data  

Microsoft Academic Search

Array comparative genomic hybridization (aCGH) provides a high-resolution and high-throughput technique for screening of copy number variations (CNVs) within the entire genome. This technique, compared to the conventional CGH, significantly improves the identification of chromosomal abnormalities. However, due to the random noise inherited in the imaging and hybridization process, identifying statistically significant DNA copy number changes in aCGH data is

Jie Chen; Yu-Ping Wang

2009-01-01

191

Heating of directly transmitted ions at low Mach number oblique collisionless shocks: A statistical physics formulation  

Microsoft Academic Search

In a previous study the authors analysed the evolution of the ion velocity distribution across a stationary exactly perpendicular one-dimensional model shock profile from a statistical physics perspective. The appropriate solution of Liouville's equation (which was shown to be different to the classical Hamiltonian solution) has the property that contours of equal phase space probability do not correspond to contours

S. W. Ellacott; W. P. Wilkinson

2007-01-01

192

The Numbers Game: How To Fatten Your Budget by Using Statistics.  

ERIC Educational Resources Information Center

Describes how three public library youth librarians used statistics to justify budget requests, change resource allocations, expand services, and show benefits of new services to the community. Examples are provided under the following headings: Show what's missing; Show what's gone wrong; Show what's going right; Show inequities; and Compare and…

Fiore, Carole D.

1998-01-01

193

Static Numbers to Dynamic Statistics: Designing a Policy-Friendly Social Policy Indicator Framework  

ERIC Educational Resources Information Center

In line with the economic crisis and rapid socio-demographic changes, the interest in "social" and "well-being" indicators has been revived. Social indicator movements of the 1960s resulted in the establishment of social indicator statistical frameworks; that legacy has remained intact in many national governments and international organisations.…

Ahn, Sang-Hoon; Choi, Young Jun; Kim, Young-Mi

2012-01-01

194

Estimating the number of clusters in a dataset via the Gap statistic  

Microsoft Academic Search

We propose a method (the \\\\Gap statistic") for estimating the numberof clusters (groups) in a set of data. The technique uses the outputof any clustering algorithm (e.g. k-means or hierarchical), comparingthe change in within cluster dispersion to that expected under an appropriatereference null distribution. Some theory is developed forthe proposal and a simulation study that shows that the Gap statisticusually

Robert Tibshirani; Guenther Walther; Trevor Hastie

2000-01-01

195

Health Conditions and Impairments Causing Disability. Disabililty Statistics Abstract, Number 16.  

ERIC Educational Resources Information Center

This statistical digest presents data on the prevalence of disabling conditions among the civilian noninstitutionalized population of the United States. Data were obtained from the National Health Interview Survey, consisting of 49,401 household interviews with 128,412 people in 1992. Disability is defined as a limitation in social or other…

LaPlante, Mitchell P.

196

Financial Statistics, 1980-81. Our Colleges and Universities Today. Volume XIX, Number 8.  

ERIC Educational Resources Information Center

Financial statistics for Pennsylvania colleges and universities for the fiscal year (FY) ending 1981, for 1971-1972 through 1980-1981, and for 1977-1978 through 1980-1981 are presented, along with narrative descriptions of financial trends at the institutions. Information includes the following: current-funds revenues by institutional control;…

Hottinger, Gerald W.

197

Diesel Ultrafine/Fine Particle Emissions in Numbers:Statistical Modeling and Evaluation of Engine Operating Variables.  

National Technical Information Service (NTIS)

This work aims to develop statistical models for ultrafine/fine particle number emission rates from a diesel bus, to evaluate the explanatory power of engine operating variables. Emissions were recorded by using on-board instrumentation in two types of re...

O. Gao Y. Kamaria-Nakis

2009-01-01

198

Turbulence statistics in fully developed channel flow at low Reynolds number  

Microsoft Academic Search

A direct numerical simulation of a turbulent channel flow is performed. The unsteady Navier-Stokes equations are solved numerically at a Reynolds number of 3300, based on the mean centerline velocity and channel half-width, with about 4 million grid points. All essential turbulence scales are resolved on the computational grid and no subgrid model is used. A large number of turbulence

John Kim; Parviz Moin; Robert Moser

1987-01-01

199

Static Numbers to Dynamic Statistics: Designing a Policy-Friendly Social Policy Indicator Framework  

Microsoft Academic Search

In line with the economic crisis and rapid socio-demographic changes, the interest in ‘social’ and ‘well-being’ indicators\\u000a has been revived. Social indicator movements of the 1960s resulted in the establishment of social indicator statistical frameworks;\\u000a that legacy has remained intact in many national governments and international organisations. With this background, this research\\u000a examines whether existing social indicator frameworks are valid

Sang-Hoon Ahn; Young Jun Choi; Young-Mi Kim

200

Statistical Test Suite for Random and Pseudorandom Number Generators for Cryptographic Applications.  

National Technical Information Service (NTIS)

This paper discusses some aspects of selecting and testing random and pseudorandom number generators. The outputs of such generators may he used in many cryptographic applications, such as the generation of key material. Generators suitable for use in cry...

A. Rukhin J. Soto J. Nechvatal M. Smid E. Barker

2001-01-01

201

Reynolds number influence on statistical behaviors of turbulence in a circular free jet  

NASA Astrophysics Data System (ADS)

The present paper examines the effect of Reynolds number on turbulence properties in the transition region of a circular jet issuing from a smoothly contracting nozzle. Hot-wire measurements were performed for this investigation through varying the jet-exit Reynolds number Red (? Ujd/?, where Uj, d, and ? are the jet-exit mean velocity, nozzle diameter, and kinematic viscosity) approximately from Red ~ 4 × 103 to Red ~ 2 × 104. Results reveal that the rates of the mean flow decay and spread vary with Reynolds number for Red < 104 and tend to become Reynolds-number independent at Red >= 104. Even more importantly, the small-scale turbulence properties, e.g., the mean rate of dissipation of kinetic energy (?), the Kolmogorov and Taylor microscales, are found to vary in different forms over the Red ranges of Red > 104 and Red < 104. Namely, the critical Reynolds number appears to occur at Red,cr ~ 104 across which the jet turbulence behaves distinctly. Two turbulence regimes are therefore identified: (i) developing or partially developed turbulence at Red < Red,cr and (ii) fully developed turbulence at Red >= Red,cr. It is suggested that the energy dissipation rate (DR) can be expressed as ?~?Uc2/R2 in regime (i) and ?~Uc3/R in regime (ii), where Uc and R are the centerline (or maximum) mean velocity and half-radius at which the mean velocity is 0.5Uc. In addition, the critical Reynolds number appears to vary from flow to flow.

Mi, J.; Xu, M.; Zhou, T.

2013-07-01

202

Photon and carbon ion irradiation of a rat prostate carcinoma: does a higher fraction number increase the metastatic rate?  

PubMed

In a recent published study, we investigated the response of an experimental prostate carcinoma (R3327-AT1) after irradiation with 1, 2 or 6 fractions of carbon ions or photons, respectively. The original intention of this study was to measure the dose-dependent local control probability as well as the related relative biological effectiveness of carbon ions. However, we now report an increased metastatic rate when the number of fractions was increased from 2 to 6. In a total of 246 animals, the actuarial metastatic rates for 1, 2 and 6 fractions were 5.1 ± 3.5%, 5.7 ± 4.0% and 15.3 ± 7.1% for photons and 9.8 ± 7.5%, 4.0 ± 3.9% and 20.3 ± 6.5% for carbon ions, respectively. The increase was significant only for carbon ions (6 vs. 2 fractions,P = 0.03). Although the original experiment was not designed to investigate metastatic rates, this observation may be of general interest to researchers studying radiation-modulated metastatic activity. PMID:24844648

Karger, Christian P; Scholz, Michael; Huber, Peter E; Debus, Jürgen; Peschke, Peter

2014-06-01

203

Observation of the squeezed state of microwave photon by resolving the even-number Fock states in circuit QED  

NASA Astrophysics Data System (ADS)

We theoretically propose an elegant way to detect the microwave parametric down conversion in the circuit QED system. The qubit energy splitting E01 is tuned to be quite close to the fundamental frequency ? {1 }of the microwave photon and the frequency of the pump beam is chosen to be ? 2. We place the qubit at the two-thirds away from the center of the central resonator, which will make the capacitive coupling to the third harmonic mode to be negligible. Since the qubit acts as an optical coupler in our system, one may expect that the following process a2+a1+a3 may appear and compete with the squeezing process a1+a1+a2, which will seriously degrade the quality of squeezing by mixing into the channel. Since the coupling to the third harmonic mode is negligible for our system, we expect instead to observe the clear squeezing of the microwave photon with frequency ? 1. We calculate the absorption spectrum of the qubit, which is experimentally measurable and will clearly reveal the squeezed states as the coherent superposition of the even-number Fock states.

Moon, Kyungsun

2013-03-01

204

General Aviation Statistics: Hours and Miles Flown, Number of Aircraft, Fuel Consumption, Production, Accidents, Air Taxi.  

National Technical Information Service (NTIS)

Contents: Eligible registered general aviation aircraft on record with FAA--December 31, 1967 and 1962; Eligible aircraft registered with FAA by type and by state and other area--December 31, 1967; Number of aircraft and estimated hours flown in general a...

S. M. Goring

1969-01-01

205

Experimental study of threshold voltage fluctuation due to statistical variation of channel dopant number in MOSFET's  

Microsoft Academic Search

Threshold voltage fluctuation has been experimentally studied, using a newly developed test structure utilizing an 8 k-NMOSFET array. It has been experimentally shown that both Vth and the channel dopant number na distributions are given as the Gaussian function, and verified that the standard deviation of na , can be expressed as the square root of the average of na

T. Mizuno; J. Okumtura; A. Toriumi

1994-01-01

206

A Statistical Evaluation of Multiplicative Congruential Random Number Generators with Modulus 2 — 1  

Microsoft Academic Search

This article presents the results of empirically testing 16 alternative multipliers for a multiplicative congruential random number generator with modulus 2 — 1. Two of the multipliers are in common use, six are the best of 50 candidate multipliers according to the theoretical spectral and lattice tests, and eight are the worst, with regard to 2-tuples, among the 50. The

George S. Fishman; Louis R. Moore

1982-01-01

207

Average Annual Health Care Use and Expenses for Influenza, 2001-2003. Statistical Brief Number 116.  

National Technical Information Service (NTIS)

Influenza, also known as flu, is a viral infection in the nose, throat, and lungs caused by a number of different strains of the influenza virus. For the very young, those with chronic conditions, those with compromised immune systems, and the elderly, in...

A. Soni S. C. Hill

2006-01-01

208

A statistical method to detect chromosomal regions with DNA copy number alterations using SNP-array-based CGH data  

Microsoft Academic Search

Abstract Single nucleotide polymorphism,(SNP) arrays were used to detect chromosomal,regions with DNA copy number,alterations. Current statistical methods,for microarray-based comparative,genomic,hybridization (array-CGH) analysis generally assume,certain relationships among adjacent markers on the same chromosome, and these assumptions may be questionable. For an SNP-array-based CGH study, multiple normal reference SNP arrays were collected. In order to utilize these normal reference SNP arrays, we derived

Yinglei Lai; Hongyu Zhao

2005-01-01

209

A statistical method to detect chromosomal regions with DNA copy number alterations using SNP-array-based CGH data  

Microsoft Academic Search

Single nucleotide polymorphism (SNP) arrays were used to detect chromosomal regions with DNA copy number alterations. Current statistical methods for microarray-based comparative genomic hybridization (array-CGH) analysis generally assume certain relationships among adjacent markers on the same chromosome, and these assumptions may be questionable. For an SNP-array-based CGH study, multiple normal reference SNP arrays were collected. In order to utilize these

Yinglei Lai; Hongyu Zhao

210

Number needed to sacrifice: statistical taboo or decision-making tool?  

PubMed Central

The percentage that benefit from medical preventive measures is small but all are exposed to the risk of side effects so most of those harmed would never benefit from their use. There is no expression or acronym to describe the ratio of harm to benefit nor discussion of what level of harm is acceptable for what benefit. Here we describe the harm to benefit ratio (HBR) expressed as number harmed (H) for 100 to benefit (B) and calculated for commonly used medical interventions. For post TIA carotid endarterectomy the HBR is 25 (25 postoperative strokes or deaths are caused for 100 to be stroke free at 5 years); warfarin in atrial fibrillation in patients aged under 65 results in 400 intracerebral haemorrhages for every 100 saved from a thromboembolic event; fibrinolytic treatment for stroke causes 44 symptomatic intracranial haemorrhages for every 100 that have minimal disability at 3 months; aspirin in high risk patients causes 33 major bleeds for every 100 occlusive vascular events prevented; routine inpatient thromboprophylaxis causes 133 additional bleeds for every 100 pulmonary emboli prevented; breast cancer screening causes 1000 unnecessary cancer treatments for 100 cancer deaths to be prevented. Conclusion: The HBR or number needed to sacrifice is larger than most imagine. Its wider use would allow us better to recognise the number harmed, allow better informed consent, compare different preventive strategies and understand the risks as well as benefits of preventive treatments.

Trewby, Peter

2013-01-01

211

Higher-order photon correlations in pulsed photonic crystal nanolasers  

SciTech Connect

We report on the higher-order photon correlations of a high-{beta} nanolaser under pulsed excitation at room temperature. Using a multiplexed four-element superconducting single-photon detector we measured g{sup (n)}(0-vector) with n=2,3,4. All orders of correlation display partially chaotic statistics, even at four times the threshold excitation power. We show that this departure from coherence and Poisson statistics is due to the quantum fluctuations associated with the small number of photons at the lasing threshold.

Elvira, D.; Hachair, X.; Braive, R.; Beaudoin, G.; Robert-Philip, I.; Sagnes, I.; Abram, I.; Beveratos, A. [Laboratoire de Photonique et Nanostructures LPN-CNRS UPR20, Route de Nozay, F-91460 Marcoussis (France); Verma, V. B.; Baek, B.; Nam, S. W.; Stevens, M. J. [National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305 (United States); Dauler, E. A. [Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, Massachusetts 02420 (United States)

2011-12-15

212

Identifying Copy Number Variants under Selection in Geographically Structured Populations Based on F-statistics  

PubMed Central

Large-scale copy number variants (CNVs) in the human provide the raw material for delineating population differences, as natural selection may have affected at least some of the CNVs thus far discovered. Although the examination of relatively large numbers of specific ethnic groups has recently started in regard to inter-ethnic group differences in CNVs, identifying and understanding particular instances of natural selection have not been performed. The traditional FST measure, obtained from differences in allele frequencies between populations, has been used to identify CNVs loci subject to geographically varying selection. Here, we review advances and the application of multinomial-Dirichlet likelihood methods of inference for identifying genome regions that have been subject to natural selection with the FST estimates. The contents of presentation are not new; however, this review clarifies how the application of the methods to CNV data, which remains largely unexplored, is possible. A hierarchical Bayesian method, which is implemented via Markov Chain Monte Carlo, estimates locus-specific FST and can identify outlying CNVs loci with large values of FST. By applying this Bayesian method to the publicly available CNV data, we identified the CNV loci that show signals of natural selection, which may elucidate the genetic basis of human disease and diversity.

Song, Hae-Hiang; Hu, Hae-Jin; Seok, In-Hae; Chung, Yeun-Jun

2012-01-01

213

Statistics of unstable periodic orbits of a chaotic dynamical system with a large number of degrees of freedom  

NASA Astrophysics Data System (ADS)

For a simple model of chaotic dynamical systems with a large number of degrees of freedom, we find that there is an ensemble of unstable periodic orbits (UPOs) with the special property that the expectation values of macroscopic quantities can be calculated using only one UPO sampled from the ensemble. Evidence to support this conclusion is obtained by generating the ensemble by Monte Carlo calculation for a statistical mechanical model described by a space-time Hamiltonian that is expressed in terms of Floquet exponents of UPOs. This result allows us to interpret the recent interesting discovery that statistical properties of turbulence can be obtained from only one UPO [G. Kawahara and S. Kida, J. Fluid Mech. 449, 291 (2001); S. Kato and M. Yamada, Phys. Rev. E 68, 025302(R) (2003)].

Kawasaki, Mitsuhiro; Sasa, Shin-Ichi

2005-09-01

214

Health Statistics  

MedlinePLUS

... a medical procedure. These are all types of health statistics. Health statistics are numbers about some aspect of health. Statistics about births, deaths, marriages, and divorces are sometimes ...

215

Filtering of the absolute value of photon-number difference for two-mode macroscopic quantum superpositions  

NASA Astrophysics Data System (ADS)

We discuss a device capable of filtering out two-mode states of light with mode populations differing by more than a certain threshold, while not revealing which mode is more populated. It would allow engineering of macroscopic quantum states of light in a way which is preserving specific superpositions. As a result, it would enhance optical phase estimation with these states as well as distinguishability of “macroscopic” qubits. We propose an optical scheme, which is a relatively simple, albeit nonideal, operational implementation of such a filter. It uses tapping of the original polarization two-mode field, with a polarization-neutral beam splitter of low reflectivity. Next, the reflected beams are suitably interfered on a polarizing beam splitter. It is oriented such that it selects unbiased polarization modes with respect to the original ones. The more an incoming two-mode Fock state is unequally populated, the more the polarizing beam-splitter output modes are equally populated. This effect is especially pronounced for highly populated states. Additionally, for such states we expect strong population correlations between the original fields and the tapped one. Thus, after a photon-number measurement of the polarizing beam-splitter outputs, a feed-forward loop can be used to let through a shutter the field, which was transmitted by the tapping beam splitter. This happens only if the counts at the outputs are roughly equal. In such a case, the transmitted field differs strongly in occupation number of the two modes, while information on which mode is more populated is nonexistent (a necessary condition for preserving superpositions).

Stobi?ska, M.; Töppel, F.; Sekatski, P.; Buraczewski, A.; ?ukowski, M.; Chekhova, M. V.; Leuchs, G.; Gisin, N.

2012-12-01

216

Statistical and hydrodynamic properties of double-ring polymers with a fixed linking number between twin rings  

NASA Astrophysics Data System (ADS)

For a double-ring polymer in solution we evaluate the mean-square radius of gyration and the diffusion coefficient through simulation of off-lattice self-avoiding double polygons consisting of cylindrical segments with radius rex of unit length. Here, a self-avoiding double polygon consists of twin self-avoiding polygons which are connected by a cylindrical segment. We show numerically that several statistical and dynamical properties of double-ring polymers in solution depend on the linking number of the constituent twin ring polymers. The ratio of the mean-square radius of gyration of self-avoiding double polygons with zero linking number to that of no topological constraint is larger than 1, in particular, when the radius of cylindrical segments rex is small. However, the ratio is almost constant with respect to the number of vertices, N, and does not depend on N. The large-N behavior of topological swelling is thus quite different from the case of knotted random polygons.

Uehara, Erica; Deguchi, Tetsuo

2014-01-01

217

Quantum nondemolition measurement of photon number via optical Kerr effect in an ultra-high-Q microtoroid cavity.  

PubMed

We theoretically investigate a quantum nondemolition (QND) measurement with optical Kerr effect in an ultra-high-Q microtoroidal system. The analytical and numerical results predict that the present QND measurement scheme possesses a high sensitivity, which allows for detecting few photons or even single photons. Ultra-high-Q toroidal microcavity may provide a novel experimental platform to study quantum physics with nonlinear optics at low light levels. PMID:19104576

Xiao, Yun-Feng; Ozdemir, Sahin Kaya; Gaddam, Venkat; Dong, Chun-Hua; Imoto, Nobuyuki; Yang, Lan

2008-12-22

218

Dependence of spectral shape of bremsstrahlung spectra on atomic number of target materials in the photon energy range of 5-30 keV  

NASA Astrophysics Data System (ADS)

Dependence of spectral shape of total bremsstrahlung spectra i.e. the sum of ordinary bremsstrahlung (OB) and polarization bremsstrahlung (PB), on the atomic number ( Z) of target materials (Al, Ti, Sn and Pb), produced by continuous beta particles of 90Sr and 204Tl, has been investigated in the photon energy region of 5-30 keV. It has been found that the spectral shape of total bremsstrahlung spectra, in terms of S ( k, Z) i.e. the number of photons of energy k per moc2 per beta disintegration, is not linearly dependent on the atomic number ( Z) of the target material and rather it is proportional to Zn. At lower photon energies, the index values ' n' of Z-dependence are much higher than unity, which is due to the larger contribution of PB into OB. The decrease in ' n' values with increase of photon energy is due to the decrease in contribution of PB into OB. It is clear that the index ' n' values obtained from the modified Elwert factor (relativistic) Bethe-Heitler theory, which include the contribution PB into OB, are in agreement with the experimentally measured results using X-PIPS Si(Li) detector. Hence the contribution of PB into the formation of a spectral shape of total bremsstrahlung spectra plays a vital role.

Singh, Tajinder; Kahlon, K. S.; Dhaliwal, A. S.

2012-02-01

219

Studies on effective atomic numbers for photon energy absorption and electron density of some narcotic drugs in the energy range 1 keV-20 MeV  

NASA Astrophysics Data System (ADS)

Effective atomic numbers for photon energy absorption ZPEA,eff, photon interaction ZPI,eff and for electron density Nel, have been calculated by a direct method in the photon-energy region from 1 keV to 20 MeV for narcotic drugs, such as Heroin (H), Cocaine (CO), Caffeine (CA), Tetrahydrocannabinol (THC), Cannabinol (CBD), Tetrahydrocannabivarin (THCV). The ZPEA,eff, ZPI,eff and Nel values have been found to change with energy and composition of the narcotic drugs. The energy dependence ZPEA,eff, ZPI,eff and Nel is shown graphically. The maximum difference between the values of ZPEA,eff, and ZPI,eff occurs at 30 keV and the significant difference of 2 to 33% for the energy region 5-100 keV for all drugs. The reason for these differences is discussed.

Gounhalli, Shivraj G.; Shantappa, Anil; Hanagodimath, S. M.

2013-04-01

220

The local enhancement of radiation dose from photons of MeV energies obtained by introducing materials of high atomic number into the treatment region.  

PubMed

With the advent of therapeutic radiation treatment machines with photon end point energies of several MeV, a new channel is available to transfer the photon energy to biological material, namely, pair production. This process has a photon threshold energy of 1.02 MeV. The probability of pair production, which depends on the square of the atomic number (Z) of the interacting material, increases markedly as the photon energy is further increased. As the goal of treatment planning in radiation therapy is to locally maximize the absorbed dose in abnormal cells and minimize the dose in surrounding normal cells, in this study the authors measured the dose enhancement which could be expected if a high-Z material such as gold was present adjacent to tumor sites during irradiation. The authors used photon beams produced by electron accelerators with energies ranging from 6 to 25 MV. They chose either gold or lead foils as high-Z materials, the measurements being repeated using the same geometry but replacing the high-Z materials with a low-Z material (aluminum). The comparison of the experimental results using low- and high-Z materials verified the theoretical prediction of the expected dose enhancement. The effect of finite range of the electron-positron pairs was also studied by varying the spacing between two foils placed parallel or orthogonal to the incident photon beam. Using an 18 MV photon beam, the authors observed a maximum dose enhancement of 44%. They intend therefore to proceed from these phantom studies to animal measurements. PMID:19746788

Alkhatib, Ahmad; Watanabe, Yoichi; Broadhurst, John H

2009-08-01

221

Statistical tests and chaotic synchronization based pseudorandom number generator for string bit sequences with application to image encryption  

NASA Astrophysics Data System (ADS)

Recently, a stream encryption scheme using d-bit segment sequences has been proposed. This scheme may generate key avalanche effect. The randomness tests of d-bit segment pseudorandom number generator will be important for implementing such a scheme. Firstly this paper extends Beker and Piper's binary pseudorandom sequence statistical test suite to d-bit segment sequences case. Secondly, a novel 3-dimensional polynomial discrete chaotic map (3DPDCM) is proposed. The calculated Lyapunov exponents of the 3DPCDM are 0.213, 0.125 and - 3.228. Using the 3DPDCM constructs a 6-dimensional generalized synchronization chaotic system. Based on this system, a 8-bit segment chaotic pseudorandom number generator (CPRNG) is introduced. Using the generalized test suite tests 100 key streams generated via the 8-bit PRNG with different initial conditions and perturbed system parameters. The tested results are similar to those of the key streams generated via RC4 PRNG. As an application, using the key streams generated via the CPRNG and the RC4 PRNG encrypts an RGB image Landscape. The results have shown that the encrypted RGB images have significant avalanche effects. This research suggests that the requirements for PRNGs are not as strict as those under the traditional avalanche criteria. Suitable designed chaos-based d-bit string PRNGs may be qualified candidates for the stream encryption scheme with avalanche effect.

Hao, Longjie; Min, Lequan

2014-05-01

222

Nanoscale optical detector with single-photon and multiphoton sensitivity.  

PubMed

We present the first nanoscale (down to approximately 50 x 50 nm(2)) detector displaying single-photon sensitivity and a nanosecond response. This type of nanodetector can also be operated in multiphoton mode, where the detection threshold can be set at N = 1, 2, 3, or 4 photons, thus allowing the mapping of photon number statistics on the nanoscale. Its operation principle based on that of hot-spot formation in superconducting nanowires allies the temporal resolution and sensitivity of superconducting single-photon detectors with subwavelength resolution and photon number discrimination. Such detectors can be of great interest for the study of nanophotonic devices at low temperature. PMID:20698610

Bitauld, David; Marsili, Francesco; Gaggero, Alessandro; Mattioli, Francesco; Leoni, Roberto; Nejad, Saeedeh Jahanmiri; Lévy, Francis; Fiore, Andrea

2010-08-11

223

Summary Health Statistics for U.S. Adults: National Health Interview Survey, 2008. Vital and Health Statistics, Series 10, Number 242.  

National Technical Information Service (NTIS)

This report presents health statistics from the 2008 National Health Interview Survey for the civilian noninstitutionalized adult population, classified by sex, age, race and ethnicity, education, family income, poverty status, health insurance coverage, ...

2008-01-01

224

Vital and Health Statistics, Series 10, Number 205. Summary Health Statistics for U.S. Adults: National Health Interview Survey, 1997.  

National Technical Information Service (NTIS)

This report presents health statistics from the 1997 National Health Interview Survey for the civilian noninstitutionalized adult population, classified by sex, age, race and Hispanic origin, poverty status, region of residence, and where appropriate, edu...

2002-01-01

225

Vital and Health Statistics Series 10, Number 251. Summary Health Statistics for the U.S. Population: National Health Interview Survey, 2010.  

National Technical Information Service (NTIS)

This report presents both age-adjusted and unadjusted health statistics from the 2010 National Health Interview Survey (NHIS) for the civilian noninstitutionalized population of the United States, classified by sex, age, race, Hispanic origin, education, ...

2011-01-01

226

Vital and Health Statistics Series 10, Number 248: Summary Health Statistics for the U.S. Population: National Health Interview Survey, 2009.  

National Technical Information Service (NTIS)

This report presents both age-adjusted and unadjusted health statistics from the 2009 National Health Interview Survey (NHIS) for the civilian noninstitutionalized population of the United States, classified by sex, age, race, Hispanic or Latino origin an...

2010-01-01

227

Vital and Health Statistics, Series 10, Number 221. Summary Health Statistics for U.S. Children: National Health Interview Survey, 2002.  

National Technical Information Service (NTIS)

This report presents both age-adjusted and unadjusted statistics from the 2002 National Health Interview Survey on selected health measures for children under 18 years of age, classified by sex, age, race, Hispanic origin, family structure, parent's educa...

2004-01-01

228

Vital and Health Statistics, Series 10, Number 239, January 2009. Summary Health Statistics for U.S. Children: National Health Interview Survey, 2007.  

National Technical Information Service (NTIS)

This report presents both age-adjusted and unadjusted statistics from the 2006 National Health Interview Survey (NHIS) on selected health measures for children under 18 years of age, classified by sex, age, race, Hispanic origin, family structure, parent ...

B. Bloom G. Freeman R. A. Cohen

2009-01-01

229

Vital and Health Statistics, Series 10, Number 231, December 2006. Summary Health Statistics for U.S. Children: National Health Interview Survey, 2005.  

National Technical Information Service (NTIS)

This report presents both age-adjusted and unadjusted statistics from the 2005 National Health Interview Survey (NHIS) on selected health measures for children under 18 years of age, classified by sex, age, race, Hispanic origin, family structure, parent ...

A. N. Dey B. Bloom G. Freeman

2006-01-01

230

Vital and Health Statistics, Series 10, Number 234, September 2007. Summary Health Statistics for U.S. Children: National Health Interview Survey, 2006.  

National Technical Information Service (NTIS)

This report presents both age- adjusted and unadjusted statistics from the 2006 National Health Interview Survey (NHIS) on selected health measures for children under 18 years of age, classified by sex, age, race, Hispanic origin, family structure, parent...

B. Bloom R. A. Cohen

2007-01-01

231

Vital and Health Statistics, Series 10, Number 227, February 2006. Summary Health Statistics for U.S. Children: National Health Interview Survey, 2004.  

National Technical Information Service (NTIS)

This report presents both age-adjusted and unadjusted statistics from the 2004 National Health Interview Survey (NHIS) on selected health measures for children under 18 years of age, classified by sex, age, race, Hispanic origin, family structure, parent'...

A. N. Dey B. Bloom

2006-01-01

232

Vital and Health Statistics, Series 10, Number 223, March 2005. Summary Health Statistics for U.S. Children: National Health Interview Survey, 2003.  

National Technical Information Service (NTIS)

This report presents both age-adjusted and unadjusted statistics from the 2003 National Health Interview Survey (NHIS) on selected health for children under 18 years of age, classified by sex, age, race, Hispanic origin, family structure, parents educatio...

A. N. Dey B. Bloom

2003-01-01

233

A new approach to mathematical statistics involving the number of degrees of freedom, temperature, and symplectically conjugate quantities  

NASA Astrophysics Data System (ADS)

We introduce several new notions in mathematical statistics that bridge the gap between this discipline and statistical physics. The analogy between them is useful both for mathematics and for physics. What is more, this new mathematical statistics is adequate for the study of computer networks and self-teaching systems. The role of the web in sociological and economic research is ascertained.

Maslov, V. P.; Maslova, T. V.

2013-07-01

234

Titanium-based transition-edge photon number resolving detector with 98% detection efficiency with index-matched small-gap fiber coupling.  

PubMed

We have realized a high-detection-efficiency photon number resolving detector at an operating wavelength of about 850 nm. The detector consists of a titanium superconducting transition edge sensor in an optical cavity, which is directly coupled to an optical fiber using an approximately 300-nm gap. The gap reduces the sensitive area and heat capacity of the device, leading to high photon number resolution of 0.42 eV without sacrificing detection efficiency or signal response speed. Wavelength dependent efficiency in fiber-coupled devices, which is due to optical interference between the fiber and the device, is also decreased to less than 1% in this configuration. The overall system detection efficiency is 98%±1% at wavelengths of around 850 nm, which is the highest value ever reported in this wavelength range. PMID:21263626

Fukuda, Daiji; Fujii, Go; Numata, Takayuki; Amemiya, Kuniaki; Yoshizawa, Akio; Tsuchida, Hidemi; Fujino, Hidetoshi; Ishii, Hiroyuki; Itatani, Taro; Inoue, Shuichiro; Zama, Tatsuya

2011-01-17

235

A_phot: Photon Asymmetry  

NASA Astrophysics Data System (ADS)

Photon asymmetry is a novel robust substructure statistic for X-ray cluster observations with only a few thousand counts; it exhibits better stability than power ratios and centroid shifts and has a smaller statistical uncertainty than competing substructure parameters, allowing for low levels of substructure to be measured with confidence. A_phot computes the photon asymmetry (A_phot) parameter for morphological classification of clusters and allows quantifying substructure in samples of distant clusters covering a wide range of observational signal-to-noise ratios. The python scripts are completely automatic and can be used to rapidly classify galaxy cluster morphology for large numbers of clusters without human intervention.

Nurgaliev, Daniyar

2013-12-01

236

Investigation of the photon statistics of parametric fluorescence in a traveling-wave parametric amplifier by means of self-homodyne tomography.  

PubMed

Photon-number distributions for parametric fluorescence from a nondegenerate optical parametric amplifier are measured with a novel self-homodyne technique. These distributions exhibit the thermal-state character predicted by theory. However, a difference between the fluorescence gain and the signal gain of the parametric amplifier is observed. We attribute this difference to a change in the signal-beam profile during the traveling-wave pulsed amplification process. PMID:18091796

Vasilyev, M; Choi, S K; Kumar, P; D'Ariano, G M

1998-09-01

237

Exposure to Alcoholism in the Family: United States, 1988. Advance Data from Vital and Health Statistics of the National Center for Health Statistics. Number 205.  

ERIC Educational Resources Information Center

This report is based on data from the 1988 National Health Interview Survey on Alcohol (NHIS-Alcohol), part of the ongoing National Health Interview Survey conducted by the National Center for Health Statistics. Interviews for the NHIS are conducted in person by staff of the United States Bureau of the Census. Information is collected on each…

Schoenborn, Charlotte A.

238

Trends in Fertility in the United States. Vital and Health Statistics, Data from the National Vital Statistics System. Series 21, Number 28.  

ERIC Educational Resources Information Center

This report presents and interprets birth statistics for the United States with particular emphasis on changes that took place during the period 1970-73. Data for the report were based on information entered on birth certificates collected from all states. The majority of the document comprises graphs and tables of data, but there are four short…

Taffel, Selma

239

Higher-order photon statistics of single-mode laser diodes and microchip solid-state lasers  

Microsoft Academic Search

We examine higher-order photon statisitics of laser diodes (LDs) and microchip solid-state lasers (SSLs). When the lasers are operated above lasing threshold, significantly different features of fluctuations are exhibited, which are the result of the asymmetric non-Gaussian distribution characteristics that are always present in SSLs, whereas, in contrast, Gaussian fluctuation persists in LDs. It is found that the deterministic dynamic

Tsong-Shin Lim; Jyh-Long Chern; Kenju Otsuka

2002-01-01

240

TRANS-STAT: statistics for environmental studies, Number 16. Extreme value statistics applied to environmental radionuclide studies: Chapters 7 and 8  

SciTech Connect

The commonly used procedure for estimating the Extreme Value distribution of a sequence of measurements implicitly assumes the samples are from a stationary random process. This ignores the well known systematic and cyclic trends that typically occur. Ignoring these trends tends to overestimate the magnitude of the extremes and their associated statistics. This chapter has presented a procedure for including such trends within the parameter estimation algorithm. The result is a better estimate of extreme values.

Gilbert, R.O.; Kinnison, R.R.

1981-08-01

241

Statistical performance evaluation and comparison of a Compton medical imaging system and a collimated Anger camera for higher energy photon imaging.  

PubMed

In radionuclide treatment, tumor cells are primarily destroyed by charged particles emitted by the compound while associated higher energy photons are used to image the tumor in order to determine radiation dose and monitor shrinkage. However, the higher energy photons are difficult to image with conventional collimated Anger cameras, since a tradeoff exists between resolution and sensitivity, and the collimator septal penetration and scattering is increased due to the high energy photons. This research compares imaging performance of the conventional Anger camera to a Compton imaging system that can have improved spatial resolution and sensitivity for high energy photons because this tradeoff is decoupled, and the effect of Doppler broadening at higher gamma energies is decreased. System performance is analyzed by the modified uniform Cramer-Rao bound (M-UCRB) algorithms based on the developed system modeling. The bound shows that the effect of Doppler broadening is the limiting factor for Compton camera performance for imaging 364.4 keV photons emitted from 131I. According to the bound, the Compton camera outperforms the collimated system for an equal number of detected events when the desired spatial resolution for a 26 cm diameter uniform disk object is better than 12 mm FWHM. For a 3D cylindrical phantom, the lower bound on variance for the collimated camera is greater than for the Compton imaginer over the resolution range from 0.5 to 2 cm FWHM. Furthermore, the detection sensitivity of the proposed Compton imaging system is about 15-20 times higher than that of the collimated Anger camera. PMID:19015578

Han, Li; Rogers, W Leslie; Huh, Sam S; Clinthorne, Neal

2008-12-21

242

Statistical performance evaluation and comparison of a Compton medical imaging system and a collimated Anger camera for higher energy photon imaging  

NASA Astrophysics Data System (ADS)

In radionuclide treatment, tumor cells are primarily destroyed by charged particles emitted by the compound while associated higher energy photons are used to image the tumor in order to determine radiation dose and monitor shrinkage. However, the higher energy photons are difficult to image with conventional collimated Anger cameras, since a tradeoff exists between resolution and sensitivity, and the collimator septal penetration and scattering is increased due to the high energy photons. This research compares imaging performance of the conventional Anger camera to a Compton imaging system that can have improved spatial resolution and sensitivity for high energy photons because this tradeoff is decoupled, and the effect of Doppler broadening at higher gamma energies is decreased. System performance is analyzed by the modified uniform Cramer-Rao bound (M-UCRB) algorithms based on the developed system modeling. The bound shows that the effect of Doppler broadening is the limiting factor for Compton camera performance for imaging 364.4 keV photons emitted from 131I. According to the bound, the Compton camera outperforms the collimated system for an equal number of detected events when the desired spatial resolution for a 26 cm diameter uniform disk object is better than 12 mm FWHM. For a 3D cylindrical phantom, the lower bound on variance for the collimated camera is greater than for the Compton imaginer over the resolution range from 0.5 to 2 cm FWHM. Furthermore, the detection sensitivity of the proposed Compton imaging system is about 15-20 times higher than that of the collimated Anger camera.

Han, Li; Rogers, W. Leslie; Huh, Sam S.; Clinthorne, Neal

2008-12-01

243

Usage Statistics  

MedlinePLUS

... Topics Drugs & Supplements Videos & Cool Tools ESPAÑOL MedlinePlus Statistics To use the sharing features on this page, please enable JavaScript. Quarterly User Statistics Graph | Quarterly User Statistics Table | Number of Health ...

244

Energy dependence of effective atomic numbers for photon energy absorption and photon interaction: studies of some biological molecules in the energy range 1 keV-20 MeV.  

PubMed

Effective atomic numbers for photon energy absorption, Z(PEA,eff), and for photon interaction, Z(PI,eff), have been calculated by a direct method in the photon-energy region from 1 keV to 20 MeV for biological molecules, such as fatty acids (lauric, myristic, palmitic, stearic, oleic, linoleic, linolenic, arachidonic, and arachidic acids), nucleotide bases (adenine, guanine, cytosine, uracil, and thymine), and carbohydrates (glucose, sucrose, raffinose, and starch). The Z(PEA,eff) and Z(PI,eff) values have been found to change with energy and composition of the biological molecules. The energy dependence of the mass attenuation coefficient, Z(PEA,eff), and the mass energy-absorption coefficient, Z(PI,eff), is shown graphically and in tabular form. Significant differences of 17%-38% between Z(PI,eff) and Z(PEA,eff) occur in the energy region 5-100 keV. The reasons for these differences, and for using Z(PEA,eff) rather than Z(PI,eff) in calculations of the absorbed dose, are discussed. PMID:18293593

Manohara, S R; Hanagodimath, S M; Gerward, L

2008-01-01

245

Publications from the National Center for Health Statistics: Volume 1, Number 4, September 1998 (on CD-ROM).  

National Technical Information Service (NTIS)

Product contains the full text of Health, United States, 1996-1997 and other recent publications of the National Center for Health Statistics (NCHS). These publications can be viewed, searched, printed, and downloaded using the Adobe Acrobat TM software o...

1998-01-01

246

Publications from the National Center for Health Statistics: Volume 1, Number 6, July 2000 (on CD-ROM).  

National Technical Information Service (NTIS)

The full text of Health, United States, 2000, and other recent publications of the National Center for Health Statistics (NCHS) are contained on the CD. These publications can be viewed, searched, printed, and downloaded using the Adobe Acrobat software o...

2000-01-01

247

Health Statistics NSW: getting the right balance between privacy and small numbers in a web-based reporting system.  

PubMed

Health Statistics NSW is a new web-based application developed by the Centre for Epidemiology and Research at the NSW Ministry of Health. The application is designed to be an efficient vehicle for the timely delivery of health statistics to a diverse audience including the general public, health planners, researchers, students and policy analysts. The development and implementation of this web application required the consideration of a series of competing demands such as: the public interest in providing health data while maintaining the privacy interests of the individuals whose health is being reported; reporting data at spatial scales of relevance to health planners while maintaining the statistical integrity of any inferences drawn; the use of hardware and software systems which are publicly accessible, scalable and robust, while ensuring high levels of security. These three competing demands and the relationships between them are discussed in the context of Health Statistics NSW. PMID:22487325

Scandol, James P; Moore, Helen A

2012-01-01

248

Statistical analysis of the spontaneously emitted photon signals from palm and dorsal sides of both hands in human subjects.  

PubMed

Photon signals emitted spontaneously from dorsal and palm sides of both hands were recorded using 6000 time windows of size T=50 ms in 50 healthy human subjects. These photon signals demonstrated universal behaviour by variance and mean. The data sets for larger time windows up to T=50s were obtained by merging the data recorded with T=50 ms. The behaviour of Fano factor regarding different window sizes was investigated. The Fano factor hovered around one in signals up to T=3s and increased slowly with the increase in window size. This indicated super-Poissonian distribution of photo counts. The Fano factor curve F(T) obtained by averaging all subjects and locations had a characteristic shape. Data suggest that the shape is essentially a combination of a smaller sub-population of individuals with sub-Poissonian and a larger sub-population with predominantly super-Poissonian photo count distribution. Averaging the data obtained by randomly shuffling observed data sets was flat and did not show any structure with T. The same applied both to the observed background data sets and the data sets obtained by randomly shuffling background in 50 measurements. The Fano factor was also flat in 50 measurements documented both by a standard LED as well as its shuffled data sets. The structure in the shape F(T) is characteristic of human signals. It may contain valuable information about metabolic processes and may have diagnostic relevance. PMID:20417114

Van Wijk, Eduard P A; Wijk, Roeland Van; Bajpai, Rajendra P; van der Greef, Jan

2010-06-01

249

Determination of Particle Size and Number Density of Opaque Colloidal Mixtures Using Diffuse Photon Density Waves and Two-Wavelength Light Sources  

NASA Astrophysics Data System (ADS)

A diffuse photon density wave (DPDW) propagates as a spherical energy wave in highly scattering media, such as opaque colloidal mixtures. The advantage of using DPDW is that the absorption and reduced scattering coefficients of the opaque colloidal mixtures can be measured without dilution and calibration. We propose a method for the estimation of the mean particle size and number density of the opaque colloidal mixtures using the relationship between estimated values and optical properties. In this study, we first determined the mean particle size and number density of colloidal silica, a single-particle dispersive medium, to confirm the validity of the method and evaluated the accuracy of the measurement. Then, we determined the mean particle size and number density of casein micelles and fat globules in milk, which is regarded as a typical opaque colloidal mixture, using two light sources with different wavelengths.

Taniguchi, Jun; Murata, Hiroshi; Okamura, Yasuyuki

2007-05-01

250

Estimation of effective atomic numbers of some solutions for photon energy absorption in the energy region 0.2-1.5 MeV: An alternative method  

NASA Astrophysics Data System (ADS)

The effective atomic numbers ( ZPEAeff), which are used to describe the composite materials in terms of equivalent elements, have been estimated in some solutions for photon energy absorption in the energy region 0.2-1.5 MeV. Since the mass energy absorption ( ?en/ ?) and mass attenuation coefficients ( ?/ ?) remain more or less the same for any given material in the photon energy region 0.2-1.5 MeV where Compton scattering is the main dominant photon interaction process, semi-empirical relations including both ?en/ ? and ?/ ? have been constituted as a function of energy. These parameters were then used to obtain ZPEAeff with the help of a Z-wise interpolation procedure. The results were compared with the experimental as well as other theoretical estimations wherever possible. Consequently, the present method is found to be readily applicable to the given solutions in order to estimate accurate values of ZPEAeff for which it is not possible to directly obtain experimentally using the conventional gamma spectrometry system.

Kurudirek, Murat

2011-12-01

251

U.S. Students Abroad: Statistics on Study Abroad, 1985/86. IIE Research Report Number 16.  

ERIC Educational Resources Information Center

Statistics are provided on U.S. students overseas, with data coming from the Study Abroad Survey, a survey of 2,896 accredited U.S. institutions of higher education with 1,898 responding for a 65% response rate. Details are provided on the characteristics and destinations of the 48,483 students abroad. Reasons for the increase in study abroad…

Zikopoulos, Marianthi, Ed.

252

Pre-Statistical Process Control: Making Numbers Count! JobLink Winning at Work Instructor's Manual, Module 3.  

ERIC Educational Resources Information Center

This instructor's manual for workplace trainers contains the materials required to conduct a course in pre-statistical process control. The course consists of six lessons for workers and two lessons for supervisors that discuss the following: concepts taught in the six lessons; workers' progress in the individual lessons; and strategies for…

Coast Community Coll. District, Costa Mesa, CA.

253

Anthropometry of Women of the U.S. Army -- 1977. Report Number 2. The Basic Univariate Statistics.  

National Technical Information Service (NTIS)

This report, the second in a series, summarizes the univariate statistics obtained in an anthropometric survey of women in the U.S. Army conducted at Fort Sam Houston, Texas; Fort McClellan, Alabama; Walter Reed Medical Center, the District of Columbia; a...

E. Churchill J. T. McConville R. M. White T. Churchill

1977-01-01

254

From Physics to Number Theory via Noncommutative Geometry. Part I: Quantum Statistical Mechanics of Q-lattices  

Microsoft Academic Search

This is the first installment of a paper in three parts, where we use noncommutative geometry to study the space of commensurability classes of Q-lattices and we show that the arithmetic properties of KMS states in the corresponding quantum statistical mechanical system, the theory of modular Hecke algebras, and the spectral realization of zeros of L-functions are part of a

Alain Connes; Matilde Marcolli

2004-01-01

255

Survey of Mathematics and Statistics Departments at Higher Education Institutions. Higher Education Surveys Report. Survey Number 5.  

ERIC Educational Resources Information Center

The purpose of this survey report is to provide national estimates on the types of students served, the characteristics of faculty used at different instructional levels, the availability and qualifications of teaching and research staff, student enrollment in mathematics/statistics courses, types of degrees offered, and problems in resources…

Chaney, Bradford, Comp.; And Others

256

Determination of confidence limits for experiments with low numbers of counts. [Poisson-distributed photon counts from astrophysical sources  

NASA Technical Reports Server (NTRS)

Two different methods, classical and Bayesian, for determining confidence intervals involving Poisson-distributed data are compared. Particular consideration is given to cases where the number of counts observed is small and is comparable to the mean number of background counts. Reasons for preferring the Bayesian over the classical method are given. Tables of confidence limits calculated by the Bayesian method are provided for quick reference.

Kraft, Ralph P.; Burrows, David N.; Nousek, John A.

1991-01-01

257

Statistical Studies on Protein Polymorphism in Natural Populations. III. Distribution of Allele Frequencies and the Number of Alleles per Locus  

PubMed Central

With the aim of understanding the mechanism of maintenance of protein polymorphism, we have studied the properties of allele frequency distribution and the number of alleles per locus, using gene-frequency data from a wide range of organisms (mammals, birds, reptiles, amphibians, Drosophila and non-Drosophila invertebrates) in which 20 or more loci with at least 100 genes were sampled. The observed distribution of allele frequencies was U-shaped in all of the 138 populations (mostly species or subspecies) examined and generally agreed with the theoretical distribution expected under the mutation-drift hypothesis, though there was a significant excess of rare alleles (gene frequency, 0 ? 0.05) in about a quarter of the populations. The agreement between the mutation-drift theory and observed data was quite satisfactory for the numbers of polymorphic (gene frequency, 0.05 ? 0.95) and monomorphic (0.95 ? 1.0) alleles.—The observed pattern of allele-frequency distribution was incompatible with the prediction from the overdominance hypothesis. The observed correlations of the numbers of rare alleles, polymorphic alleles and monomorphic alleles with heterozygosity were of the order of magnitude that was expected under the mutation-drift hypothesis. Our results did not support the view that intracistronic recombination is an important source of genetic variation. The total number of alleles per locus was positively correlated with molecular weight in most of the species examined, and the magnitude of the correlation was consistent with the theoretical prediction from mutation-drift hypothesis. The correlation between molecular weight and the number of alleles was generally higher than the correlation between molecular weight and heterozygosity, as expected.

Chakraborty, Ranajit; Fuerst, Paul A.; Nei, Masatoshi

1980-01-01

258

Two-state theory of binned photon statistics for a large class of waiting time distributions and its application to quantum dot blinking.  

PubMed

A theoretical method is proposed for the calculation of the photon counting probability distribution during a bin time. Two-state fluorescence and steady excitation are assumed. A key feature is a kinetic scheme that allows for an extensive class of stochastic waiting time distribution functions, including power laws, expanded as a sum of weighted decaying exponentials. The solution is analytic in certain conditions, and an exact and simple expression is found for the integral contribution of "bright" and "dark" states. As an application for power law kinetics, theoretical results are compared with experimental intensity histograms from a number of blinking CdSe/ZnS quantum dots. The histograms are consistent with distributions of intensity states around a "bright" and a "dark" maximum. A gap of states is also revealed in the more-or-less flat inter-peak region. The slope and to some extent the flatness of the inter-peak feature are found to be sensitive to the power-law exponents. Possible models consistent with these findings are discussed, such as the combination of multiple charging and fluctuating non-radiative channels or the multiple recombination center model. A fitting of the latter to experiment provides constraints on the interaction parameter between the recombination centers. Further extensions and applications of the photon counting theory are also discussed. PMID:24929377

Volkán-Kacsó, Sándor

2014-06-14

259

Two-state theory of binned photon statistics for a large class of waiting time distributions and its application to quantum dot blinking  

NASA Astrophysics Data System (ADS)

A theoretical method is proposed for the calculation of the photon counting probability distribution during a bin time. Two-state fluorescence and steady excitation are assumed. A key feature is a kinetic scheme that allows for an extensive class of stochastic waiting time distribution functions, including power laws, expanded as a sum of weighted decaying exponentials. The solution is analytic in certain conditions, and an exact and simple expression is found for the integral contribution of "bright" and "dark" states. As an application for power law kinetics, theoretical results are compared with experimental intensity histograms from a number of blinking CdSe/ZnS quantum dots. The histograms are consistent with distributions of intensity states around a "bright" and a "dark" maximum. A gap of states is also revealed in the more-or-less flat inter-peak region. The slope and to some extent the flatness of the inter-peak feature are found to be sensitive to the power-law exponents. Possible models consistent with these findings are discussed, such as the combination of multiple charging and fluctuating non-radiative channels or the multiple recombination center model. A fitting of the latter to experiment provides constraints on the interaction parameter between the recombination centers. Further extensions and applications of the photon counting theory are also discussed.

Volkán-Kacsó, Sándor

2014-06-01

260

Protein stability by number: high-throughput and statistical approaches to one of protein science's most difficult problems  

PubMed Central

Most proteins are only barely stable, which impedes research, complicates therapeutic applications, makes proteins susceptible to pathologically destabilizing mutations. Our ability to predict the thermodynamic consequences of even single point mutations is still surprisingly limited, and established methods of measuring stability are slow. Recent advances are bringing protein stability studies into the high-throughput realm. Some methods are based on inferential read-outs such as activity, proteolytic resistance or split-protein fragment reassembly. Other methods use miniaturization of direct measurements, such as intrinsic fluorescence, H/D exchange, cysteine reactivity, aggregation and hydrophobic dye binding (DSF). Protein engineering based on statistical analysis (consensus and correlated occurrences of amino acids) is promising, but much work remains to understand and implement these methods.

Magliery, Thomas J.; Lavinder, Jason J.; Sullivan, Brandon J.

2011-01-01

261

Protein stability by number: high-throughput and statistical approaches to one of protein science's most difficult problems.  

PubMed

Most proteins are only barely stable, which impedes research, complicates therapeutic applications, and makes proteins susceptible to pathologically destabilizing mutations. Our ability to predict the thermodynamic consequences of even single point mutations is still surprisingly limited, and established methods of measuring stability are slow. Recent advances are bringing protein stability studies into the high-throughput realm. Some methods are based on inferential read-outs such as activity, proteolytic resistance or split-protein fragment reassembly. Other methods use miniaturization of direct measurements, such as intrinsic fluorescence, H/D exchange, cysteine reactivity, aggregation and hydrophobic dye binding (DSF). Protein engineering based on statistical analysis (consensus and correlated occurrences of amino acids) is promising, but much work remains to understand and implement these methods. PMID:21498105

Magliery, Thomas J; Lavinder, Jason J; Sullivan, Brandon J

2011-06-01

262

Applying dissipative dynamical systems to pseudorandom number generation: Equidistribution property and statistical independence of bits at distances up to logarithm of mesh size  

NASA Astrophysics Data System (ADS)

The behavior of a family of dissipative dynamical systems representing transformations a of a two-dimensional torus is studied on a discrete lattice and compared with that of conservative hyperbolic automorphisms of the torus. Applying dissipative dynamical systems to generation of pseudorandom numbers is shown to be advantageous and equidistribution of probabilities for the sequences of bits can be achieved. A new algorithm for generating uniform pseudorandom numbers is proposed. The theory of the generator, which includes proofs of periodic properties and of statistical independence of bits at distances up to logarithm of mesh size, is presented. Extensive statistical testing using available test packages demonstrates excellent results, while the speed of the generator is comparable to other modern generators.

Barash, L. Yu.

2011-07-01

263

A statistical study of the cross-shock electric potential at low Mach number, quasi-perpendicular bow shock crossings using Cluster data  

NASA Astrophysics Data System (ADS)

The cross-shock electrostatic potential at the front of collision-less shocks plays a key role in the distribution of energy at the shock front. Multipoint measurements such as those provided by the Cluster II mission provide an ideal framework for the study of the cross-shock potential because of their ability to distinguish between temporal and spacial variations at the shock front. We present a statistical study of the cross-shock potential calculated for around 50 crossings of the terrestrial bow shock. The statistical dependency of the normalized (with resect to upstream ion kinetic energy) cross-shock potential (?K) on the upstream Alfvén Mach number is in good agreement with analytical results that predict decrease of ?k with increasing Mach number.

Dimmock, A. P.; Balikhin, M. A.; Krasnoselskikh, V. V.; Walker, S. N.; Bale, S. D.; Hobara, Y.

2012-02-01

264

Book Trade Research and Statistics. Prices of U.S. and Foreign Published Materials; Book Title Output and Average Prices: 2001 Final and 2002 Preliminary Figures; Book Sales Statistics, 2002: AAP Preliminary Estimates; U.S. Book Exports and Imports:2002; Number of Book Outlets in the United States and Canada; Review Media Statistics.  

ERIC Educational Resources Information Center

Includes six reports related to book trade statistics, including prices of U.S. and foreign materials; book title output and average prices; book sales statistics; book exports and imports; book outlets in the U.S. and Canada; and numbers of books and other media reviewed by major reviewing publications. (LRW)

Sullivan, Sharon G.; Grabois, Andrew; Greco, Albert N.

2003-01-01

265

On Asymptotic Properties of a Number Theoretic Function Arising out of a Spin Chain Modelin Statistical Mechanics  

NASA Astrophysics Data System (ADS)

Let Let N be a positive integer and define ?(N) as the number of matrices, C, which are products of A and B, where both A and B must occur, such that the trace, Tr(C)=N. It has been conjectured that see [10]. In this note we consider the summatory function and show that

Kallies, J.; Özlük, A.; Peter, M.; Snyder, C.

266

Estimation of aerosol particle number distributions with Kalman Filtering - Part 1: Theory, general aspects and statistical validity  

NASA Astrophysics Data System (ADS)

Aerosol characteristics can be measured with different instruments providing observations that are not trivially inter-comparable. Extended Kalman Filter (EKF) is introduced here as a method to estimate aerosol particle number size distributions from multiple simultaneous observations. The focus here in Part 1 of the work was on general aspects of EKF in the context of Differential Mobility Particle Sizer (DMPS) measurements. Additional instruments and their implementations are discussed in Part 2 of the work. University of Helsinki Multi-component Aerosol model (UHMA) is used to propagate the size distribution in time. At each observation time (10 min apart), the time evolved state is updated with the raw particle mobility distributions, measured with two DMPS systems. EKF approach was validated by calculating the bias and the standard deviation for the estimated size distributions with respect to the raw measurements. These were compared to corresponding bias and standard deviation values for particle number size distributions obtained from raw measurements by a inversion of the instrument kernel matrix method. Despite the assumptions made in the EKF implementation, EKF was found to be more accurate than the inversion of the instrument kernel matrix in terms of bias, and compatible in terms of standard deviation. Potential further improvements of the EKF implementation are discussed.

Viskari, T.; Asmi, E.; Kolmonen, P.; Vuollekoski, H.; Petäjä, T.; Järvinen, H.

2012-12-01

267

Properties of two-mode squeezed number states  

NASA Technical Reports Server (NTRS)

Photon statistics and phase properties of two-mode squeezed number states are studied. It is shown that photon number distribution and Pegg-Barnett phase distribution for such states have similar (N + 1)-peak structure for nonzero value of the difference in the number of photons between modes. Exact analytical formulas for phase distributions based on different phase approaches are derived. The Pegg-Barnett phase distribution and the phase quasiprobability distribution associated with the Wigner function are close to each other, while the phase quasiprobability distribution associated with the Q function carries less phase information.

Chizhov, Alexei V.; Murzakhmetov, B. K.

1994-01-01

268

Statistics Explained  

NSDL National Science Digital Library

This site contains 100 modules designed to introduce concepts in statistics. The modules are divided into categories such as descriptive statistics, inferential statistics, related measures, enumeration statistics and ANOVA. Click the green button on the side to start the modules, then click "Main Menu" at the top to see a list of topics. Topics include: describing numbers, normal curve, sampling distributions, hypothesis testing, regression and Chi-Square. The site also includes a glossary, statistical tables and simulations, and a personalized progress report.

Hoffman, Howard

2009-07-14

269

Photons Revisited  

NASA Astrophysics Data System (ADS)

A systematic review of methods and data for the Monte Carlo simulation of photon interactions is in progress: it concerns a wide set of theoretical modeling approaches and data libraries available for this purpose. Models and data libraries are assessed quantitatively with respect to an extensive collection of experimental measurements documented in the literature to determine their accuracy; this evaluation exploits rigorous statistical analysis methods. The computational performance of the associated modeling algorithms is evaluated as well. An overview of the assessment of photon interaction models and results of the experimental validation are presented.

Batic, Matej; Begalli, Marcia; Han, Min Cheol; Hauf, Steffen; Hoff, Gabriela; Kim, Chan Hyeong; Kim, Han Sung; Grazia Pia, Maria; Saracco, Paolo; Weidenspointner, Georg

2014-06-01

270

Development of long-wavelength avalanche photodiodes and vertical-cavity lasers for epitaxial integration as a vertical-cavity photon number amplifier  

NASA Astrophysics Data System (ADS)

The goal of this research was to develop technology for building a vertical-geometry photon number amplifier (vertical PNA) that operates at a wavelength in the low-absorption window for optical fibers near 1.55 mum. An optical amplifier of this design would provide electrically-tappable low-noise polarization-independent optical amplification of laser pulses and serve as a stepping stone toward development of a tunable amplifying wavelength converter. The vertical PNA design consists of a multiple active region (MAR) VCSEL integrated with an avalanche photodiode of the separate absorption, charge, and multiplication layer design (SACM APD): the VCSEL is intended to operate continuous wave (CW), modulated by the APD. Both components were selected for their high gain: in excess of 10 electrons out per photon in for the APD, and slightly more than 1 photon out per electron in for the MAR VCSEL under ideal circumstances. In working toward the vertical PNA, significant technical challenges were addressed: (1) Development of a long-wavelength MAR VCSEL capable of high-temperature CW operation. Although this goal was never achieved, efforts directed to this end resulted in an investigation of basic material science issues that are vital to future improvements of the device. Better DBR and active region designs were developed, the overall thermal impedance of the structure was reduced significantly, a rudimentary optical aperture compatible with InP-based materials was tested, and loss estimates for the device were put on solid ground. (2) Development of a low-noise SACM APD capable of modulating the MAR VCSEL at high speed. Here the vital relationships between growth conditions, material quality, and APD performance were established. Other achievements include demonstration of highly uniform arrays of these devices, extremely low-noise operation, and the largest area long-wavelength APDs ever reported. (3) Successful demonstration of the epitaxial integration of these two components as a functional vertical PNA. Without a MAR VCSEL capable of CW operation, a functional vertical PNA cannot be built. Nonetheless, functional APDs and VCSELs (under pulsed operation) were separately demonstrated on vertical PNA wafers, as was a basic integration scheme.

Huntington, Andrew Sumika

271

Implication of nonintegral occupation number and Fermi-Dirac statistics in the local-spin-density approximation applied to finite systems  

SciTech Connect

In electronic-structure calculations for finite systems using the local-spin-density (LSD) approximation, it is assumed that the eigenvalues of the Kohn-Sham equation should obey Fermi-Dirac (FD) statistics. In order to comply with this assumption for some of the transition-metal atoms, a nonintegral occupation number is used which also minimizes the total energy. It is shown here that for finite systems it is not necessary that the eigenvalues of the Kohn-Sham equation obey FD statistics. It is also shown that the Kohn-Sham exchange potential used in all LSD models is correct only for integer occupation number. With a noninteger occupation number the LSD exchange potential will be smaller than that given by the Kohn-Sham potential. Ab initio self-consistent spin-polarized calculations have been performed numerically for the total energy of an iron atom. It is found that the ground state belongs to the 3d/sup 6/4s/sup 2/ configuration. The ionization potentials of all the Fe/sup n//sup +/ ions are reported and are in agreement with experiment.

Dhar, S.

1989-02-01

272

Photonic quantum well composed of photonic crystal and quasicrystal  

NASA Astrophysics Data System (ADS)

A photonic quantum well structure composed of photonic crystal and Fibonacci quasicrystal is investigated by analyzing the transmission spectra and electric field distributions. The defect band in the photonic well can form confined quantized photonic states that can change in the band-gap of the photonic barriers by varying the thickness ratio of the two stacking layers. The number of confined states can be tuned by adjusting the period of the photonic well. The photons traverse the photonic quantum well by resonance tunneling and the coupling effect leads to the high transmission intensity of the confined photonic states.

Xu, Shaohui; Zhu, Yiping; Wang, Lianwei; Yang, Pingxiong; Chu, Paul K.

2014-02-01

273

Statistical Significance  

NSDL National Science Digital Library

This article may help the user understand the concept of statistical significance and the meaning of the numbers produced by The Survey System. This article is presented in two parts. The first part simplifies the concept of statistical significance as much as possible; so that non-technical readers can use the concept to help make decisions based on their data. The second part provides more technical readers with a fuller discussion of the exact meaning of statistical significance numbers.

2008-06-30

274

Bright integrated photon-pair source for practical passive decoy-state quantum key distribution  

NASA Astrophysics Data System (ADS)

We report on a bright, nondegenerate type-I parametric down-conversion source, which is well suited for passive decoy-state quantum key distribution. We show the photon-number-resolved analysis over a broad range of pump powers and we prove heralded higher-order n-photon states up to n =4. The inferred photon click statistics exhibit excellent agreements to the theoretical predictions. From our measurement results we conclude that our source meets the requirements to avert photon-number-splitting attacks.

Krapick, S.; Stefszky, M. S.; Jachura, M.; Brecht, B.; Avenhaus, M.; Silberhorn, C.

2014-01-01

275

Photon statistics in enhanced fluorescence from a single CdSe/ZnS quantum dot in the vicinity of silver nanoparticles  

NASA Astrophysics Data System (ADS)

Single-photon emission behavior in the enhanced fluorescence from single colloidal quantum dots (QDs) near silver nanoparticles (AgNPs) was investigated using a single molecule fluorescence spectroscopy technique. It was found that the degree of fluorescence enhancement from single QDs with AgNPs increased with decrease in the lifetime and the probability of single-photon emission, that is, highly enhanced fluorescence with a shortened lifetime exhibited a low probability of single-photon emission. The present results yield new insights into fundamentals of QD-metal nanostructure interactions, and are also important to understand the mechanism of the fluorescence enhancement by localized surface plasmon of metal nanostructures.

Masuo, Sadahiro; Naiki, Hiroyuki; Machida, Shinjiro; Itaya, Akira

2009-11-01

276

Improved estimation of the noncentrality parameter distribution from a large number of t-statistics, with applications to false discovery rate estimation in microarray data analysis.  

PubMed

Given a large number of t-statistics, we consider the problem of approximating the distribution of noncentrality parameters (NCPs) by a continuous density. This problem is closely related to the control of false discovery rates (FDR) in massive hypothesis testing applications, e.g., microarray gene expression analysis. Our methodology is similar to, but improves upon, the existing approach by Ruppert, Nettleton, and Hwang (2007, Biometrics, 63, 483-495). We provide parametric, nonparametric, and semiparametric estimators for the distribution of NCPs, as well as estimates of the FDR and local FDR. In the parametric situation, we assume that the NCPs follow a distribution that leads to an analytically available marginal distribution for the test statistics. In the nonparametric situation, we use convex combinations of basis density functions to estimate the density of the NCPs. A sequential quadratic programming procedure is developed to maximize the penalized likelihood. The smoothing parameter is selected with the approximate network information criterion. A semiparametric estimator is also developed to combine both parametric and nonparametric fits. Simulations show that, under a variety of situations, our density estimates are closer to the underlying truth and our FDR estimates are improved compared with alternative methods. Data-based simulations and the analyses of two microarray datasets are used to evaluate the performance in realistic situations. PMID:22551000

Qu, Long; Nettleton, Dan; Dekkers, Jack C M

2012-12-01

277

RANDOMNESS of Numbers DEFINITION(QUERY:WHAT? V HOW?) ONLY Via MAXWELL-BOLTZMANN CLASSICAL-Statistics(MBCS) Hot-Plasma VS. Digits-Clumping Log-Law NON-Randomness Inversion ONLY BOSE-EINSTEIN QUANTUM-Statistics(BEQS) .  

NASA Astrophysics Data System (ADS)

RANDOMNESS of Numbers cognitive-semantics DEFINITION VIA Cognition QUERY: WHAT???, NOT HOW?) VS. computer-"science" mindLESS number-crunching (Harrel-Sipser-...) algorithmics Goldreich "PSEUDO-randomness"[Not.AMS(02)] mea-culpa is ONLY via MAXWELL-BOLTZMANN CLASSICAL-STATISTICS(NOT FDQS!!!) "hot-plasma" REPULSION VERSUS Newcomb(1881)-Weyl(1914;1916)-Benford(1938) "NeWBe" logarithmic-law digit-CLUMPING/ CLUSTERING NON-Randomness simple Siegel[AMS Joint.Mtg.(02)-Abs. # 973-60-124] algebraic-inversion to THE QUANTUM and ONLY BEQS preferentially SEQUENTIALLY lower-DIGITS CLUMPING/CLUSTERING with d = 0 BEC, is ONLY VIA Siegel-Baez FUZZYICS=CATEGORYICS (SON OF TRIZ)/"Category-Semantics"(C-S), latter intersection/union of Lawvere(1964)-Siegel(1964)] category-theory (matrix: MORPHISMS V FUNCTORS) "+" cognitive-semantics" (matrix: ANTONYMS V SYNONYMS) yields Siegel-Baez FUZZYICS=CATEGORYICS/C-S tabular list-format matrix truth-table analytics: MBCS RANDOMNESS TRUTH/EMET!!!

Siegel, Z.; Carl-Ludwig Siegel, Edward

2011-03-01

278

Velocity and temperature derivatives in high- Reynolds-number turbulent flows in the atmospheric surface layer. Part 3. Temperature and joint statistics of temperature and velocity derivatives  

NASA Astrophysics Data System (ADS)

This is part 3 of our work describing experiments in which explicit information was obtained on all the derivatives, i.e. spatial derivatives, xj, and temporal derivatives, t, of velocity and temperature fields (and all the components of velocity fluctuations and temperature) at the Reynolds number Re?~104.This part is devoted to the issues concerning temperature with the emphasis on joint statistics of temperature and velocity derivatives, based on preliminary results from a jet facility and the main results from a field experiment. Apart from a number of conventional results, these contain a variety of results concerning production of temperature gradients, such as role of vorticity and strain, eigen-contributions, geometrical statistics such as alignments of the temperature gradient and the eigenframe of the rate-of-strain tensor, tilting of the temperature gradient, comparison of the true production of the temperature gradient with its surrogate. Among the specific results of importance is the essential difference in the behaviour of the production of temperature gradients in regions dominated by vorticity and strain. Namely, the production of temperature gradients is much more intensive in regions dominated by strain, whereas production of temperature gradients is practically independent of the magnitude of vorticity. In contrast, vorticity and strain are contributing equally to the tilting of the vector of temperature gradients.The production of temperature gradients is mainly due to the fluctuative strain, the terms associated with mean fields are unimportant. It was checked directly (by looking at corresponding eigen-contributions and alignments), that the production of the temperature gradients is due to predominant compressing of fluid elements rather than stretching, which is true of other processes in turbulent flows, e.g. turbulent energy production in shear flows. Though the production of the temperature gradient and its surrogate possess similar univariate PDFs (which indicates the tendency to isotropy in small scales by this particular criterion), their joint PDF is not close to a bisector. This means that the true production of the temperature gradient is far from being fully represented by its surrogate. The main technical achievement is demonstrating the possibility of obtaining experimentally joint statistics of velocity and temperature gradients.

Gulitski, G.; Kholmyansky, M.; Kinzelbach, W.; L?Thi, B.; Tsinober, A.; Yorish, S.

279

Statistical Software,  

National Technical Information Service (NTIS)

This article is a detailed discussion of several classes of statistical software including subroutine libraries, software systems, languages and software/hardware combinations. A comparison of a large number of packages is made across 16 classes of statis...

A. R. Hayes E. J. Wegman

1988-01-01

280

Bias-free true random-number generator.  

PubMed

We propose what we believe to be a new approach to nondeterministic random-number generation. The randomness originated from the uncorrelated nature of consecutive laser pulses with Poissonian photon statistics and that of photon number detections is used to generate random bit, and the von Neumann correction method is used to extract the final random bit. This method is proved to be bias free in randomness generation, provided that the single photon detections are mutually independent. Further, it has the advantage in fast random bit generation, since no postprocessing is needed. A true random-number generator based on this method is realized, and its randomness is tested and guaranteed using three statistical test batteries. PMID:19529733

Wei, Wei; Guo, Hong

2009-06-15

281

Low-bias high-speed quantum random number generator via shaped optical pulses.  

PubMed

We present an optical quantum random number generator (QRNG) based on the digitized time interval between random photon arrivals. By tailoring the photon flux of the laser diode, the statistics of the waiting-time distribution are altered to approximate the ideal, uniform case. This greatly reduces the need for post-processing, and enables fast, secure quantum random number generation at rates exceeding 110 Mbit/s. PMID:20588781

Wayne, Michael A; Kwiat, Paul G

2010-04-26

282

THE STATISTICAL DETECTION OF THRESHOLD SIGNALS IN THE RETINA  

Microsoft Academic Search

For the human retina, Hecht, Shlaer, and Pireune (1942) concluded that statistical fluctuations in response to brief flashes at the absolute threshold could be accounted for entirely by random fluctuations in the number of photons absorbed by the photoreceptors at each flash, and that \\

R. Fitzhugh

1957-01-01

283

Digest of Education Statistics, 2012. NCES 2014-015 [Appendix A: Guide to Sources; Appendix B: Definitions; Appendix C: Index of Table Numbers  

ERIC Educational Resources Information Center

The 2012 edition of the "Digest of Education Statistics" is the 48th in a series of publications initiated in 1962. The "Digest" has been issued annually except for combined editions for the years 1977-78, 1983-84, and 1985-86. Its primary purpose is to provide a compilation of statistical information covering the broad field…

Snyder, Thomas D.; Dillow, Sally A.

2013-01-01

284

Digest of Education Statistics, 2011. NCES 2012-001 [Appendix A: Guide to Sources; Appendix B: Definitions; Appendix C: Index of Table Numbers  

ERIC Educational Resources Information Center

The 2011 edition of the "Digest of Education Statistics" is the 47th in a series of publications initiated in 1962. The "Digest" has been issued annually except for combined editions for the years 1977-78, 1983-84, and 1985-86. Its primary purpose is to provide a compilation of statistical information covering the broad field…

Snyder, Thomas D.; Dillow, Sally A.

2012-01-01

285

National Vital Statistics Reports, Volume 49, Number 2. Comparability of Cause of Death between ICD-9 and ICD-10: Preliminary Estimates.  

National Technical Information Service (NTIS)

This report presents preliminary results describing the effects of implementing the Tenth Revision of the 'International Classification of Diseases' (ICD-10) on mortality statistics for selected causes of death effective with deaths occurring in the Unite...

R. N. Anderson A. M. Minino D. L. Hoyert H. M. Rosenberg

2001-01-01

286

Photon calorimeter  

DOEpatents

A photon calorimeter is provided that comprises a laminar substrate that is uniform in density and homogeneous in atomic composition. A plasma-sprayed coating, that is generally uniform in density and homogeneous in atomic composition within the proximity of planes that are parallel to the surfaces of the substrate, is applied to either one or both sides of the laminar substrate. The plasma-sprayed coatings may be very efficiently spectrally tailored in atomic number. Thermocouple measuring junctions, are positioned within the plasma-sprayed coatings. The calorimeter is rugged, inexpensive, and equilibrates in temperature very rapidly. 4 figs.

Chow, Tze-Show

1988-04-22

287

Photon-photon collisions  

SciTech Connect

The study of photon-photon collisions has progressed enormously, stimulated by new data and new calculational tools for QCD. In the future we can expect precise determinations of ..cap alpha../sub s/ and ..lambda../sup ms/ from the ..gamma..*..gamma.. ..-->.. ..pi../sup 0/ form factor and the photon structure function, as well as detailed checks of QCD, determination of the shape of the hadron distribution amplitudes from ..gamma gamma.. ..-->.. H anti H, reconstruction of sigma/sub ..gamma gamma../ from exclusive channels at low W/sub ..gamma gamma../, definitive studies of high p/sub T/ hadron and jet production, and studies of threshold production of charmed systems. Photon-photon collisions, along with radiative decays of the psi and UPSILON, are ideal for the study of multiquark and gluonic resonances. We have emphasized the potential for resonance formation near threshold in virtually every hadronic exclusive channel, including heavy quark states c anti c c anti c, c anti c u anti u, etc. At higher energies SLC, LEP, ...) parity-violating electroweak effects and Higgs production due to equivalent Z/sup 0/ and W/sup + -/ beams from e ..-->.. eZ/sup 0/ and e ..-->.. nu W will become important. 44 references.

Brodsky, S.J.

1985-01-01

288

Photon-photon collisions  

NASA Astrophysics Data System (ADS)

The study of photon-photon collisions has progressed, stimulated by new data and new calculational tools for QCD. In the future precise determination are expected of (ALPHA)/sub s/ and (LAMBDA)/sup ms/ from the (GAMMA)*(GAMMA) (YIELDS) (PI) (0) form factor and the photon structure function, and detailed checks of QCD, determination of the shape of the hadron distribution amplitudes from (GAMMA) (GAMMA) (YIELDS) H anti-H, reconstruction of sigma/sub (GAMMA) (GAMMA)/ from exclusive channels at low W/sub (GAMMA)(GAMMA/, definitive studies of high p/sub T/ hadron and jet production, and studies of threshold production of charmed systems. Photon-photon collisions, along with radiative decays of the psi and UPSILON, are ideal for the study of multiquark and gluonic resonances. The potential for resonance formation near threshold in virtually every hadronic exclusive channel, including heavy quark states c anti c c anti c, c anti c u anti u, are emphasized. At higher energies SLC, LEP, ...) parity-violating electroweak effects and Higgs production due to equivalent Z(0) and W(+-) beams from e (YIELDS) eZ(0) and e (YIELDS) nu W will be important.

Brodsky, S. J.

1985-01-01

289

Photonic Aharonov-Bohm effect in photon-phonon interactions.  

PubMed

The Aharonov-Bohm effect is one of the most intriguing phenomena in both classical and quantum physics, and associates with a number of important and fundamental issues in quantum mechanics. The Aharonov-Bohm effects of charged particles have been experimentally demonstrated and found applications in various fields. Recently, attention has also focused on the Aharonov-Bohm effect for neutral particles, such as photons. Here we propose to utilize the photon-phonon interactions to demonstrate that photonic Aharonov-Bohm effects do exist for photons. By introducing nonreciprocal phases for photons, we observe experimentally a gauge potential for photons in the visible range based on the photon-phonon interactions in acousto-optic crystals, and demonstrate the photonic Aharonov-Bohm effect. The results presented here point to new possibilities to control and manipulate photons by designing an effective gauge potential. PMID:24476790

Li, Enbang; Eggleton, Benjamin J; Fang, Kejie; Fan, Shanhui

2014-01-01

290

Quantum dots in photonic crystals: from quantum information processing to single photon nonlinear optics  

NASA Astrophysics Data System (ADS)

Quantum dots in photonic crystals are interesting both as a testbed for fundamental cavity quantum electrodynamics (QED) experiments, as well as a platform for quantum and classical information processing. Quantum dot-photonic crystal cavity QED has been probed both in photoluminescence and coherently, by resonant light scattering from such a system [1]. In the latter case, both intensity and photon statistics of the reflected beam have been analyzed as a function of wavelength, leading to observation of effects such as photon blockade and photon induced tunneling - for the first time in solid state [2]. The system has also been employed to achieve a controlled phase and amplitude modulation between two modes of light at the single photon level [3] - nonlinearity observed so far only in atomic physics systems. These demonstrations lie at the core of a number of proposals for quantum information processing, and could also be employed to build novel devices, such as optical switches controlled at a single photon level. [4pt] [1] Dirk Englund, Andrei Faraon, Ilya Fushman, Nick Stoltz, Pierre Petroff, and Jelena Vuckovic, ``Controlling cavity reflectivity with a single quantum dot," Nature ,ol. 450, No. 7171, pp. 857-861, December 2007[0pt] [2] Andrei Faraon, Ilya Fushman, Dirk Englund, Nick Stoltz, Pierre Petroff, and Jelena Vuckovic, ``Coherent generation of nonclassical light on a chip via photon-induced tunneling and blockade," Nature Physics ,ol. 4, pp. 859 - 863 (2008)[0pt] [3] Ilya Fushman, Dirk Englund, Andrei Faraon, Nick Stoltz, Pierre Petroff, and Jelena Vuckovic, ``Controlled phase shift with a single quantum dot," Science ,ol. 320, number 5877, pp. 769-772 ( 2008)

Vuckovic, Jelena

2009-05-01

291

Energy-resolved detection of single infrared photons with ? = 8 ?m using a superconducting microbolometer  

NASA Astrophysics Data System (ADS)

We report on the detection of single photons with ? = 8 ?m using a superconducting hot-electron microbolometer. The sensing element is a titanium transition-edge sensor with a volume ~0.1 ?m3 fabricated on a silicon substrate. Poisson photon counting statistics including simultaneous detection of 3 photons was observed. The width of the photon-number peaks was 0.11 eV, 70% of the photon energy, at 50-100 mK. This achieved energy resolution is one of the best figures reported so far for superconducting devices. Such devices can be suitable for single-photon calorimetric spectroscopy throughout the mid-infrared and even the far-infrared.

Karasik, Boris S.; Pereverzev, Sergey V.; Soibel, Alexander; Santavicca, Daniel F.; Prober, Daniel E.; Olaya, David; Gershenson, Michael E.

2012-07-01

292

Health Manpower Source Book. Manpower Supply and Educational Statistics for Selected Health Occupations: 1968. Public Health Service Publication Number 263, Section 20.  

ERIC Educational Resources Information Center

This publication is a compilation of statistics on supply and education of health manpower in medicine and osteopathy, dentistry, optometry, pharmacy, podiatry, veterinary medicine, nursing, public health, and eight selected allied health occupations. The material is organized by occupations and the following information is presented for each…

National Institutes of Health (DHEW), Bethesda, MD. Bureau of Health Professions Education and Manpower Training.

293

Photonic Crystals  

Microsoft Academic Search

In this paper, we review the early motivation for photonic crystal research which was derived from the need for a photonic bandgap in quantum optics. This led to a series of experimental and theoretical searches for the elusive photonic bandgap structures: those three-dimensionally periodic dielectric structures which are to photon waves, as semiconductor crystals are to electron waves. We shall

E. Yablonovitch

1994-01-01

294

Quantum statistics of parametric oscillation  

NASA Astrophysics Data System (ADS)

A quantum-statistical analysis of the steady-state light fields in driven parametric oscillation in a cavity is presented. Using the solution of a Fokker-Planck equation for the generalized P representation of the signal and idler modes, the mean photon numbers, second-order correlation functions, and intermode correlation function are calculated as functions of the driving field. The generalized P distribution describes the signal and idler modes' statistics over the whole range of driving-field strengths except in the region far below the oscillation threshold. The second-order correlation functions are found to violate the Cauchy-Schwartz inequality, a violation allowed because the P distribution is complex. Squeezing is also found in a linear combination of the signal and idler fields.

McNeil, K. J.; Gardiner, C. W.

1983-09-01

295

Statistical malpractice.  

PubMed

Statistical malpractice is an insidious, and indeed prestige-laden and grant-rewarded, activity. Brilliantly clever, but fundamentally wrong-headed, number-crunchers are encouraged to devise inappropriate applications of mathematical methods to health problems. This species of misdirected zealot has so far been immune from criticism. PMID:8709054

Charlton, B G

1996-01-01

296

Statistical Applets: Statistical Significance  

NSDL National Science Digital Library

Created by authors Duckworth, McCabe, Moore and Sclove for W.H. Freeman of Co., this applet is designed to help students visualize the rejection region of a statistical test by allowing them to set null and alternate hypotheses, population parameters, sample statistics, and significance level. It accompanies "ÃÂÃÂPractice of Business Statistics," but can be used without this text. Even though brief, this is a nice interactive resource for an introductory statistics course.

Duckworth, William; Mccabe, George; Moore, David; Sclove, Stanley

2009-03-05

297

Statistical Bits and Pieces: Status Dropout Rates and Number and Distribution of 16- through 24-Year-Olds Who Were Dropouts, by Background Characteristics: October 1998.  

ERIC Educational Resources Information Center

Presents data on dropout rates and number and distribution of adolescents/young adults who were dropouts, noting background characteristics (sex, race/ethnicity, age, recency of immigration, and region) for October 1998. Data are provided on status dropout rate, number status dropouts, total population age 16-24 years, percent of all dropouts, and…

Journal of At-Risk Issues, 2001

2001-01-01

298

An Unsupervised Segmentation with an Adaptive Number of Clusters Using Cloude-Pottier Decomposition, Wishart Test Statistic and MCCV A lgorithm for Fully Polarimetric Sar Data Analysis  

NASA Astrophysics Data System (ADS)

In this paper, an unsupervised segmentation method is proposed for fully polarimetric SAR data. We introduce the MCCV algorithm to automatically estimate the optimal number of clusters from the data inner structure. The experimental results show that the number of classes is a crucial point for the unsupervised segmentation, which will strictly affect the segmentation performance. The MCCV algorithm represents to be a reliable method to estimate the appropriate number of clusters, and the pro- posed segmentation algorithm also provides better performance than the general Wishart H/?/A segmentation.

Cao, F.; Hong, W.; Wu, Y.; Pottier, E.

2007-03-01

299

Nonclassical properties and decoherence of fields in photon-added squeezing-enhanced thermal states  

NASA Astrophysics Data System (ADS)

We put forward the photon-added squeezing-enhanced thermal states (PASETS) theoretically by adding photon to the squeezed enhancing thermal states (SETS) repeatedly. Based on the normally ordered density operator of PASETS, we investigate the nonclassical behavior of the PASETS by evaluating, both analytically and numerically, Mandel's Q-parameter, photon-number distribution (PND), and Wigner function (WF). It is found that smaller squeezing parameter r and thermal photon number nc can lead to more chance of the appearance of sub-Poissonian statistics. And it is shown that the PND of PASETS exhibit more remarkable oscillations than that of SETS in stronger squeezing case. The WF exhibit partial negativity in phase space and the squeezing parameter r can result in both squeezing and rotating effect. By investigating the fidelity between PASETS and SETS shows that the fidelity tender to steady values in the high value of squeezing parameter or thermal photon number. In addition, the decoherence effect on the PASETS is examined by the time-evolution of the analytical WF in thermal channel. The results show that the PASETS shall lose nonclassicality and non-Gaussianity and reduce to classical states with Gaussian distribution after sufficient time interaction with the thermal noise. And larger photon-added number or thermal photon number shall render shorter decoherence time.

Wang, Zhen; Meng, Xiang-Guo; Li, Heng-Mei; Yuan, Hong-Chun

2014-04-01

300

Non-classical Properties of Photon-Added Compass State  

NASA Astrophysics Data System (ADS)

We investigate the observable non-classical features of the photon-added compass state (PACS) by its sub-Poissonian statistics, such as the Mandel's parameter, second-order correlation function, photon-number distribution and the quasi-probability distribution functions, peculiarly the negativity in the Wigner distribution of the PACS as the specific non-classical features. We study the squeezing properties of the PACS and find the PACS does not show squeezing properties of the quadrature. Finally, we give the non-Gaussianity of the PACS by the fidelity between the PACS and the squeezed coherent state (SCS).

Ren, Gang; ma, Jian-guo; Du, Jian-ming; Yu, Hai-jun; Zhang, Xiu-Lan

2013-10-01

301

Analytic and Special Studies Reports; Utilization of Psychiatric Facilities by Children: Current Status, Trends, Implications. Mental Health Statistics, Series B, Number 1.  

ERIC Educational Resources Information Center

Data are presented concerning the total number of children served in psychiatric facilities and the utilization of specific facilities, including outpatient psychiatric clinics, state and county mental hospitals, private mental hospitals, inpatient psychiatric services of general hospitals, psychiatric day-night services, private psychiatric…

Rosen, Beatrice M.; And Others

302

National Vital Statistics Reports, Volume 53, Number 7. Births to 10-14 Year-Old Mothers, 1990-2002: Trends and Health Outcomes.  

National Technical Information Service (NTIS)

The report presents the number and rate of U.S. births for 10-14 year olds, for 1990-2002 by race and Hispanic origin and by State. Pregnancy risk factors and outcomes by selected maternal and infant characteristics are shown. Tabular and graphical descri...

F. Menacker J. A. Martin M. F. MacDorman S. J. Ventura

2004-01-01

303

Declines in Teenage Birth Rates, 1991-97: National and State Patterns. National Vital Statistics Reports, Volume 47, Number 12, December 17, 1998.  

National Technical Information Service (NTIS)

This report presents data on the numbers of teenage births and teenage birth rates for the United States for the period 1950-97 and State-specific birth rates for teenagers for 1991-96. After increasing sharply in the late 1980s, birth rates declined for ...

S. C. Curtin, S. J. Ventura, T. J. Mathews

1998-01-01

304

Photonic crystals  

Microsoft Academic Search

A new class of composite materials has emerged which provides a means to control and manipulate light. These materials, known as photonic crystals, are periodic arrays of dielectric scatteres in homogeneous dielectric matrices. They affect the properties of photons in much the same way a semiconductor affects the properties of an electron. Consequently, photons can have band structures, localized defect

J. D. Joannopoulos; Pierre R. Villeneuve; Shanhui Fan

1997-01-01

305

Statistical reconstruction of qutrits  

Microsoft Academic Search

We discuss a procedure of measurement followed by the reproduction of the quantum state of a three-level optical system---a frequency---and spatially degenerate two-photon field. The method of statistical estimation of the quantum state based on solving the likelihood equation and analyzing the statistical properties of the obtained estimates is developed. Using the root approach of estimating quantum states, the initial

Yu. I. Bogdanov; M. V. Chekhova; L. A. Krivitsky; S. P. Kulik; A. N. Penin; A. A. Zhukov; L. C. Kwek; C. H. Oh; M. K. Tey

2004-01-01

306

Prospects for in vivo estimation of photon linear attenuation coefficients using postprocessing dual-energy CT imaging on a commercial scanner: Comparison of analytic and polyenergetic statistical reconstruction algorithms  

SciTech Connect

Purpose: Accurate patient-specific photon cross-section information is needed to support more accurate model-based dose calculation for low energy photon-emitting modalities in medicine such as brachytherapy and kilovoltage x-ray imaging procedures. A postprocessing dual-energy CT (pDECT) technique for noninvasivein vivo estimation of photon linear attenuation coefficients has been experimentally implemented on a commercial CT scanner and its accuracy assessed in idealized phantom geometries. Methods: Eight test materials of known composition and density were used to compare pDECT-estimated linear attenuation coefficients to NIST reference values over an energy range from 10 keV to 1 MeV. As statistical image reconstruction (SIR) has been shown to reconstruct images with less random and systematic error than conventional filtered backprojection (FBP), the pDECT technique was implemented with both an in-house polyenergetic SIR algorithm, alternating minimization (AM), as well as a conventional FBP reconstruction algorithm. Improvement from increased spectral separation was also investigated by filtering the high-energy beam with an additional 0.5 mm of tin. The law of propagated uncertainty was employed to assess the sensitivity of the pDECT process to errors in reconstructed images. Results: Mean pDECT-estimated linear attenuation coefficients for the eight test materials agreed within 1% of NIST reference values for energies from 1 MeV down to 30 keV, with mean errors rising to between 3% and 6% at 10 keV, indicating that the method is unbiased when measurement and calibration phantom geometries are matched. Reconstruction with FBP and AM algorithms conferred similar mean pDECT accuracy. However, single-voxel pDECT estimates reconstructed on a 1 × 1 × 3 mm{sup 3} grid are shown to be highly sensitive to reconstructed image uncertainty; in some cases pDECT attenuation coefficient estimates exhibited standard deviations on the order of 20% around the mean. Reconstruction with the statistical AM algorithm led to standard deviations roughly 40% to 60% less than FBP reconstruction. Additional tin filtration of the high energy beam exhibits similar pDECT estimation accuracy as the unfiltered beam, even when scanning with only 25% of the dose. Using the law of propagated uncertainty, low Z materials are found to be more sensitive to image reconstruction errors than high Z materials. Furthermore, it is estimated that reconstructed CT image uncertainty must be limited to less than 0.25% to achieve a target linear-attenuation coefficient estimation uncertainty of 3% at 28 keV. Conclusions: That pDECT supports mean linear attenuation coefficient measurement accuracies of 1% of reference values for energies greater than 30 keV is encouraging. However, the sensitivity of the pDECT measurements to noise and systematic errors in reconstructed CT images warrants further investigation in more complex phantom geometries. The investigated statistical reconstruction algorithm, AM, reduced random measurement uncertainty relative to FBP owing to improved noise performance. These early results also support efforts to increase DE spectral separation, which can further reduce the pDECT sensitivity to measurement uncertainty.

Evans, Joshua D., E-mail: jevans2@mcvh-vcu.edu; Yu, Yaduo; Williamson, Jeffrey F. [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States)] [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States); Whiting, Bruce R. [Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213 (United States)] [Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213 (United States); O’Sullivan, Joseph A. [Department of Electrical and Systems Engineering, Washington University, St. Louis, Missouri 63130 (United States)] [Department of Electrical and Systems Engineering, Washington University, St. Louis, Missouri 63130 (United States); Politte, David G. [Mallinckrodt Institute of Radiology, Washington University, St. Louis, Missouri 63110 (United States)] [Mallinckrodt Institute of Radiology, Washington University, St. Louis, Missouri 63110 (United States); Klahr, Paul H. [Philips Healthcare, 595 Miner Rd., Highland Hts., Ohio 44143 (United States)] [Philips Healthcare, 595 Miner Rd., Highland Hts., Ohio 44143 (United States)

2013-12-15

307

A direct determination of the number of light neutrino families from e +e -?? overline?? at LEP  

NASA Astrophysics Data System (ADS)

The L3 detector at LEP has been used to determine the number of light neutrino families by measuring the cross section of single photon even in e +e - collisions at energies near the Z 0 resonance. We have observed 61 single photon candidates with more than 1.5 GeV of deposited energy in the barrel electromagnetic calorimeter, for a total integrated luminosity of 3.0 pb -1. From a likelihood fir to the single photon cross sections, we determin N?=3.24 ± 0.46 ( statistical) ±0.22 ( systematic).

Adeva, B.; Adriani, O.; Aguilar-Benitez, M.; Akbari, H.; Alcaraz, J.; Aloisio, A.; Alverson, G.; Alviggi, M. G.; Ambrosi, G.; An, Q.; Anderhub, H.; Anderson, A. L.; Andreev, V. P.; Angelov, T.; Antonov, L.; Antreasyan, D.; Arce, P.; Arefiev, A.; Atamanchuk, A.; Azemoon, T.; Aziz, T.; Baba, P. V. K. S.; Bagnaia, P.; Bakken, J. A.; Baksay, L.; Ball, R. C.; Banerjee, S.; Bao, J.; Barillère, R.; Barone, L.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Behrens, J.; Beingessner, S.; Bencze, Gy. L.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B. L.; Biasini, M.; Biland, A.; Bilei, G. M.; Bizzarri, R.; Blaising, J. J.; Blömeke, P.; Blumenfeld, B.; Bobbink, G. J.; Bocciolini, M.; Bock, R.; Böhm, A.; Borgia, B.; Bourilkov, D.; Bourquin, M.; Boutigny, D.; Bouwens, B.; Brambilla, E.; Branson, J. G.; Brock, I. C.; Brooks, M.; Bruyant, F.; Buisson, C.; Bujak, A.; Burger, J. D.; Burger, W. J.; Burq, J. P.; Busenitz, J.; Cai, X. D.; Capell, M.; Caria, M.; Carminati, F.; Cartacci, A. M.; Cerrada, M.; Cesaroni, F.; Chang, Y. H.; Chaturvedi, U. K.; Chemarin, M.; Chen, A.; Chen, C.; Chen, G. M.; Chen, H. F.; Chen, H. S.; Chen, J.; Chen, M.; Chen, M. L.; Chen, W. Y.; Chiefari, G.; Chien, C. Y.; Chmeissani, M.; Civinni, C.; Clare, I.; Clare, R.; Coan, T. E.; Cohn, H. O.; Coignet, G.; Colino, N.; Contin, A.; Crijns, F.; Cui, X. Y.; Dai, T. S.; D'Alessandro, R.; de Asmundis, R.; Degré, A.; Deiters, K.; Dénes, E.; Denes, P.; DeNotaristefani, F.; Dhina, M.; DiBitonto, D.; Diemoz, M.; Dimitrov, H. R.; Dionisi, C.; Dova, M. T.; Drago, E.; Driever, T.; Duchesneau, D.; Duinker, P.; Duran, I.; El Mamouni, H.; Engler, A.; Eppling, F. J.; Erné, F. C.; Extermann, P.; Fabbretti, R.; Fabre, M.; Falciano, S.; Fan, Q.; Fan, S. J.; Fackler, O.; Fay, J.; Felcini, M.; Ferguson, T.; Fernandez, D.; Fernandez, G.; Ferroni, F.; Fesefeldt, H.; Fiandrini, E.; Field, J.; Filthaut, F.; Finocchiaro, G.; Fisher, P. H.; Forconi, G.; Foreman, T.; Freudenreich, K.; Friebel, W.; Fukushima, M.; Gailloud, M.; Galaktionov, Yu.; Gallo, E.; Ganguli, S. N.; Garcia-Abia, P.; Gau, S. S.; Gele, D.; Gentile, S.; Goldfarb, S.; Gong, Z. F.; Gonzalez, E.; Gordeev, A.; Göttlicher, P.; Goujon, D.; Gratta, G.; Grinnell, C.; Gruenewald, M.; Guanziroli, M.; Guo, J. K.; Gurtu, A.; Gustafson, H. R.; Gutay, L. J.; Hangarter, K.; Hasan, A.; Hauschildt, D.; He, C. T.; Hebbeker, T.; Hebert, M.; Herten, G.; Herten, U.; Hervé, A.; Hilgers, K.; Hofer, H.; Hoorani, H.; Hu, G.; Hu, G. Q.; Ille, B.; Ilyas, M. M.; Innocente, V.; Janssen, H.; Jezequel, S.; Jin, B. N.; Jones, L. W.; Kasser, A.; Khan, R. A.; Kamyshkov, Yu.; Kapinos, P.; Kapustinsky, J. S.; Karyotakis, Y.; Kaur, M.; Khokhar, S.; Kienzle-Focacci, M. N.; Kinnison, W. W.; Kirby, D.; Kirsch, S.; Kittel, W.; Klimentov, A.; König, A. C.; Kornadt, O.; Koutsenko, V.; Koulbardis, A.; Kraemer, R. W.; Kramer, T.; Krastev, V. R.; Krenz, W.; Krovshich, A.; Krizmanic, J.; Kumar, K. S.; Kumar, V.; Kunin, A.; Landi, G.; Lanius, K.; Lanske, D.; Lanzano, S.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Lee, D. M.; Leedom, I.; Le Goff, J. M.; Leistam, L.; Leiste, R.; Lenti, M.; Leonardi, E.; Lettry, J.; Leytens, X.; Li, C.; Li, H. T.; Li, J. F.; Li, P. J.; Li, Q.; Li, X. G.; Liao, J. Y.; Lin, W. T.; Lin, Z. Y.; Linde, F. L.; Lindemann, B.; Linnhofer, D.; Liu, R.; Liu, Y.; Lohmann, W.; Longo, E.; Lu, Y. S.; Lubbers, J. M.; Lübelsmeyer, K.; Luci, C.; Luckey, D.; Ludovici, L.; Luminari, L.; Ma, W. G.; MacDermott, M.; Malhorta, P. K.; Malik, R.; Malinin, A.; Maña, C.; Mao, D. N.; Mao, Y. F.; Maolinbay, M.; Marchesini, P.; Martin, J. P.; Martinez-Laso, L.; Marzano, F.; Massaro, G. G. G.; Matsuda, T.; Mazumdar, K.; McBride, P.; McMahon, T.; McNally, D.; Meinholz, Th.; Merk, M.; Merola, L.; Meschini, M.; Metzger, W. J.; Mi, Y.; Mills, G. B.; Mir, Y.; Mirabelli, G.; Mnich, J.; Möller, M.; Monteleoni, B.; Morand, R.; Morganti, S.; Moulai, N. E.; Mount, R.; Müller, S.; Nadtochy, A.; Nagy, E.; Napolitano, M.; Newman, H.; Neyer, C.; Niaz, M. A.; Niessen, L.; Nowak, H.; Organtini, G.; Pandoulas, D.; Pauluzzi, M.; Pauss, F.; Passaleva, G.; Paoletti, S.; Patricelli, S.; Pei, Y. J.; Perret-Gallix, D.; Perrier, J.; Pevsner, A.; Pieri, M.; Piroué, P. A.; Plasil, F.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Produit, N.; Qian, J. M.; Qureshi, K. N.; Raghavan, R.; Rahal-Callot, G.; Raven, G.; Razis, P.; Read, K.; Ren, D.; Ren, Z.; Rescigno, M.; Reucroft, S.; Ricker, A.; Riemann, S.; Rind, O.; Rizvi, H. A.; Roe, B. P.; Röhner, M.; Röhner, S.; Romero, L.; Rose, J.; Rosier-Lees, S.; Rosmalen, R.; Rosselet, Ph.; Rubbia, A.; Rubio, J. A.; Rykaczewski, H.; Sachwitz, M.; Salicio, J.; Salicio, J. M.; Sanders, G. S.; Santocchia, A.; Sarakinos, M. S.; Sartorelli, G.; Sauvage, G.; Savin, A.; Schegelsky, V.; Schmiemann, K.; Schmitz, D.; Schmitz, P.

1992-01-01

308

Nonreciprocal magnetic photonic crystals  

Microsoft Academic Search

We study band dispersion relations omega(k-->) of a photonic crystal with at least one of the constitutive components being a magnetically ordered material. It is shown that by proper spatial arrangement of magnetic and dielectric components one can construct a magnetic photonic crystal with strong spectral asymmetry (nonreciprocity) omega(k-->)!=omega(-k-->). The spectral asymmetry, in turn, results in a number of interesting

A. Figotin; I. Vitebsky

2001-01-01

309

Injury Statistics  

MedlinePLUS

... Data Consumer Opinion Surveys Home / Research & Statistics Injury Statistics This is the statistic reports page for scientific ... Home Appliances, Maintenance and Construction Injury Statistics Injury Statistics September 30, 2012 Submersions Related to Non-Pool ...

310

Possibility of efficient generation of multiphoton entangled states using a one-dimensional nonlinear photonic crystal  

SciTech Connect

A rigorous quantum theory for the generation of multiphoton entangled states based on two consecutive three-frequency interactions of waves in a one-dimensional nonlinear photonic crystal is developed using the field expansion and differentiation methods. The three-photon correlation coefficient and the average photon numbers generated in the structure are calculated. All order expansion terms are included in the calculation. The generation conditions for multiphoton entangled states in such a structure are also analyzed. It is shown that the created photons in the present structures obey the super-Poisson statistics at the interacting frequencies and are in a multiparticle entangled state. This means the nonlinear photonic crystal can be applied as a highly efficient source of an entangled multiphoton for highly integrated all-optical circuits.

Dong Yunxia; Zhang Xiangdong [Department of Physics, Beijing Normal University, Beijing 100875 (China)

2010-03-15

311

Photoelectron anticorrelations and sub-Poisson statistics in scintillation detectors.  

PubMed

The performance of scintillation detectors for x rays and gamma rays is limited fundamentally by the statistics of the scintillation light and the resulting photoelectrons. This paper presents a new experimental approach to studying these statistics by observing correlations in the signals from two photodetectors. It is shown that the Fano factors (ratios of variance to mean), both for the number the photoelectrons produced on the photocathode of the photomultiplier and for the underlying number of scintillation photons, can be deduced from these correlations. For LaBr(3)(Ce) and 662 keV gamma rays, the photopeak signals obtained by photomultipliers on opposite faces of a thin sample are negatively correlated, and the Fano factor for the photoelectrons is significantly less than one. The inferred Fano factor for the optical photons is very small, indistinguishable from zero within experimental error. PMID:20725609

Bousselham, Abdelkader; Barrett, Harrison H; Bora, Vaibhav; Shah, Kanai

2010-08-01

312

A critical evaluation of grid-by-number sediment sampling using laser scanner derived clast population statistics across a gravel bar  

NASA Astrophysics Data System (ADS)

Water flow level in river channels is moderated by the interaction with the roughness of the surface over which it flows. The interaction is highly complex and remains poorly understood despite its economic and social importance in flood level forecasting. The empirical and semi-rational nature of approaches used to estimate hydraulic roughness makes them very difficult to apply and much of the hydraulic resistance has been attributed to grain roughness using various forms of the Colebrook-White equation where the grain diameter is modified by a multiplier to account for the non-uniform nature of gravel-bed surfaces. Fundamental to the accuracy of the particle size approaches is the sampling of river-bed gravels where sample size, operator bias, particle shape and surface heterogeneity can greatly affect the result. Despite these problems a standard surface sample of the intermediate axis of 100 clasts remains the accepted method for grain-size characterisation amongst scientists and engineers concerned with channel hydraulics. Surface roughness has also been measured using a random field of spatial elevation data. The success of this approach has been tempered by the lack of high-resolution topographic data covering all roughness scales, however, improved data-point resolution is now achievable using terrestrial laser scanning technology. The aim here is to reliably quantify the population grain-size distribution of a natural gravel surface using random field terrestrial laser scanner x,y,z data and by direct comparison to demonstrate the errors inherent in the conventional particle-size approach. Application of the random field approach, using a terrestrial laser scanner, across a gravel bar surface on the River South Tyne at Lambley, UK, generated an effective sample of 120,000 clasts yielding a D84 for use in the Colebrook White equation of 0.110m. Monte Carlo sampling within the 12000 measured clasts from the bar surface generated 560 simulated grid-by-number D84 estimates. Grain-size D84 values ranged from 0.100m to 0.195m with a median value of 0.130m. This represents an average 18% and a maximum 77% over-estimation of the grain-size value in the flow resistance equation. Such potential errors, inherent with the conventional grid-by-number sampling technique, impact significantly on flood level estimation options.

Milan, D. J.; Heritage, G. L.

2007-12-01

313

Lifetime statistics of quantum chaos studied by a multiscale analysis  

SciTech Connect

In a series of pump and probe experiments, we study the lifetime statistics of a quantum chaotic resonator when the number of open channels is greater than one. Our design embeds a stadium billiard into a two dimensional photonic crystal realized on a silicon-on-insulator substrate. We calculate resonances through a multiscale procedure that combines energy landscape analysis and wavelet transforms. Experimental data is found to follow the universal predictions arising from random matrix theory with an excellent level of agreement.

Di Falco, A.; Krauss, T. F. [School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, KY16 9SS (United Kingdom); Fratalocchi, A. [PRIMALIGHT, Faculty of Electrical Engineering, Applied Mathematics and Computational Science, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia)

2012-04-30

314

Statistical reconstruction of qutrits  

SciTech Connect

We discuss a procedure of measurement followed by the reproduction of the quantum state of a three-level optical system--a frequency--and spatially degenerate two-photon field. The method of statistical estimation of the quantum state based on solving the likelihood equation and analyzing the statistical properties of the obtained estimates is developed. Using the root approach of estimating quantum states, the initial two-photon state vector is reproduced from the measured fourth moments in the field. The developed approach applied to quantum-state reconstruction is based on the amplitudes of mutually complementary processes. The classical algorithm of statistical estimation based on the Fisher information matrix is generalized to the case of quantum systems obeying Bohr's complementarity principle. It has been experimentally proved that biphoton-qutrit states can be reconstructed with the fidelity of 0.995-0.999 and higher.

Bogdanov, Yu.I.; Chekhova, M.V.; Krivitsky, L.A.; Kulik, S.P.; Penin, A.N.; Zhukov, A.A.; Kwek, L.C.; Oh, C.H.; Tey, M.K. [Russian Control System Agency, Angstrem', Moscow 124460 (Russian Federation); Department of Physics, Moscow M.V. Lomonosov State University, 119992 Moscow (Russian Federation); National Institute of Education Nanyang Technological University, 637616 Singapore (Singapore); Department of Physics, Faculty of Science, National University of Singapore, 117542 Singapore (Singapore)

2004-10-01

315

Photon absorptiometry  

SciTech Connect

Recently, there has been a renewed interest in the detection and treatment of osteoporosis. This paper is a review of the merits and limitations of the various noninvasive modalities currently available for the measurement of bone mineral density with special emphasis placed upon the nuclear medicine techniques of single-photon and dual-photon absorptiometry. The clinicians should come away with an understanding of the relative advantages and disadvantages of photon absorptiometry and its optimal clinical application. 49 references.

Velchik, M.G.

1987-01-01

316

The photon gas formulation of thermal radiation  

NASA Technical Reports Server (NTRS)

A statistical consideration of the energy, the linear momentum, and the angular momentum of the photons that make up a thermal radiation field was presented. A general nonequilibrium statistical thermodynamics approach toward a macroscopic description of thermal radiation transport was developed and then applied to the restricted equilibrium statistical thermostatics derivation of the energy, linear momentum, and intrinsic angular momentum equations for an isotropic photon gas. A brief treatment of a nonisotropic photon gas, as an example of the results produced by the nonequilibrium statistical thermodynamics approach, was given. The relativistic variation of temperature and the invariance of entropy were illustrated.

Ried, R. C., Jr.

1975-01-01

317

Spectral resolution in pixel detectors with single photon processing  

NASA Astrophysics Data System (ADS)

Pixel detectors based on photon counting or single photon processing readout are becoming popular for spectral X-ray imaging. The detector is based on deep submicron electronics with functions to determine the energy of each individual photon in every pixel. The system is virtually noiseless when it comes to the number of the detected photons. However noise and variations in system parameters affect the determination of the photon energy. Several factors affect the energy resolution in the system. In the readout electronics the most important factors are the threshold dispersion, the gain variation and the electronic noise. In the sensor contributions come from charge sharing, variations in the charge collection efficiency, leakage current and the statistical nature of the charge generation, as described by the Fano factor. The MEDIPIX technology offers a powerful tool for investigating these effects since energy spectra can be captured in each pixel. In addition the TIMEPIX chip, when operated in Time over Threshold mode, offers an opportunity to analyze individual photon interactions, thus addressing charge sharing and fluorescence. Effects of charge sharing and the properties of charge summing can be investigated using MEDIPIX3RX. Experiments are performed using both Si and CdTe detectors. In this paper we discuss the various contributions to the spectral noise and how they affect detector response. The statements are supported with experimental data from MEDIPIX-type detectors.

Fröjdh, C.; Krapohl, D.; Reza, S.; Fröjdh, E.; Thungström, G.; Norlin, B.

2013-09-01

318

Book Trade Research and Statistics. Prices of U.S. and Foreign Published Materials; Book Title Output and Average Prices: 2000 Final and 2001 Preliminary Figures; Book Sales Statistics, 2001: AAP Preliminary Estimates; U.S. Book Exports and Imports: 2001; Number of Book Outlets in the United States and Canada; Review Media Statistics.  

ERIC Educational Resources Information Center

Includes six articles that report on prices of U.S. and foreign published materials; book title output and average prices; book sales statistics; book exports and imports; book outlets in the U.S. and Canada; and review media statistics. (LRW)

Sullivan, Sharon G.; Barr, Catherine; Grabois, Andrew

2002-01-01

319

Adoption Statistics  

MedlinePLUS

... Role Our Leadership Newsroom Publications Statistics Contact Us Statistics All statistics correspond with the U.S. Government fiscal year, which ... and ends on September 30. For example, adoption statistics for FY2013 show the period from October 1, ...

320

Cancer Statistics  

MedlinePLUS

... 1975-2010 Did You Know? Video Series Cancer Statistics Understanding Cancer Statistics Learn definitions of statistical terms, ... and software tools. Did You Know? Colorectal Cancer Statistics You will need Adobe Flash Player 8 or ...

321

Laser diodes in photon number squeezed state  

Microsoft Academic Search

A laser diode with an intrinsic layer as the space charge limited current region is expected to emit a low noise (less than the shot noise level) light. However, when one applies the intrinsic layer to the laser diode, severe difficulty is faced. Because the intrinsic layer has a very high resistivity, the applied voltage to operate the laser diode

Syoichi Kakimoto; Kimio Shigihara; Yutaka Nagai

1997-01-01

322

PHOTON2  

NSDL National Science Digital Library

Funded through a three-year grant from the Advanced Technological Education (ATE) program of the National Science Foundation (NSF), Project PHOTON2 builds on the highly successful "Alliance" model developed through the previous Project PHOTON.In both projects, educators from several geographic locations (four to six regions nationally) are brought together to facilitate photonics technology education at their institutions that is intelligently developed and seamlessly articulated. The âÂÂAlliancesâ consist of four to six participants per region, including high school and two- and four-year college science, technology, engineering, and math instructors, as well as their institution's career and admissions counselors. On this site, visitors will find curriculum materials, information about the PHOTON2 laboratory kit and careers in photonics, links to external tutorials and applets, and societies and organizations. Visitors can also find out more about the project, its team, newsletter, conference papers, workshop, and a distance learning course for educators.

2010-10-07

323

Reliable source of conditional states from single-mode pulsed thermal fields by multiple-photon subtraction  

SciTech Connect

We demonstrate the effect of multiple-photon subtraction on the generation of conditional states in the pulsed regime. Our experimental scheme relies on a beam splitter (BS) and a pair of linear photodetectors that are able to resolve up to tens of photons. We use a single-mode thermal field at the input port of the BS to test the reliability of our scheme, and we show good agreement with the theory by fully characterizing the conditional outgoing states in terms of photon-number statistics and non-Gaussianity.

Allevi, A. [Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia U.d.R. Como, I-22100 Como (Italy); Andreoni, A. [Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia U.d.R. Como, I-22100 Como (Italy); Dipartimento di Fisica e Matematica, Universita degli Studi dell'Insubria, I-22100 Como (Italy); Bondani, M. [Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia U.d.R. Como, I-22100 Como (Italy); Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, I-22100 Como (Italy); Genoni, M. G.; Olivares, S. [Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia U.d.R. Milano Universita, I-20133 Milano (Italy); Dipartimento di Fisica, Universita degli Studi di Milano, I-20133 Milano (Italy)

2010-07-15

324

Two-photon and three-photon blockades in driven nonlinear systems  

NASA Astrophysics Data System (ADS)

Photon blockade, in analogy to Coulomb's or phonon blockades, is a phenomenon when a single photon in a nonlinear cavity blocks the transmission of a second photon. This effect can occur in Kerr-type systems driven by a laser due to strong nonlinear photon-photon interactions. We predict the occurrence of higher-order photon blockades where the transmission of more than two photons is effectively blocked by single- and two-photon states. This photon blockade can be achieved by tuning the frequency of the laser driving field to be equal to the sum of the Kerr nonlinearity and the cavity resonance frequency. We refer to this phenomenon as two-photon blockade or two-photon state truncation via nonlinear scissors, and can also be interpreted as photon-induced tunneling. We also show that, for a driving-field frequency fulfilling another resonance condition and for higher strengths of the driving field, even a three-photon blockade can occur but less clearly than in the case of single- and two-photon blockades. We demonstrate how various photon blockades can be identified by analyzing photon-number correlations, coherence and entropic properties, Wigner functions, and spectra of squeezing. We show that two- and three-photon blockades can, in principle, be observed in various cavity and circuit quantum electrodynamical systems for which the standard single-photon blockade was observed without the need of using higher-order driving interactions or Kerr media exhibiting higher-order nonlinear susceptibility.

Miranowicz, Adam; Paprzycka, Ma?gorzata; Liu, Yu-xi; Bajer, Ji?í; Nori, Franco

2013-02-01

325

Apollo by the Numbers: A Statistical Reference.  

National Technical Information Service (NTIS)

The purpose of this work is to provide researchers, students, and space enthusiasts with a comprehensive reference for facts about Project Apollo, America's effort to put humans in the Moon. Research for this work started in 1988, when the author discover...

R. Orloff

2000-01-01

326

2-photon multiqubit cluster states  

NASA Astrophysics Data System (ADS)

Cluster states of two photons and four qubits, built on the double entanglement of two photons in the degrees of freedom of polarization and linear momentum, have been used in the realization of a complete set of basic operations of one-way quantum computation. Basic computation algorithms, namely, the Grover's search and the Deutsch's algorithm, have been realized by using these states. Hyperentangled states of increasing size are of paramount importance for the realization of even more complex algorithms and can be extended to a lager number of degrees of freedom of the photons. Some recent results obtained with entangled states of two photons and six qubits are presented.

Vallone, G.; Ceccarelli, R.; Mataloni, P.

2009-01-01

327

Why do we not perceive photons?  

Microsoft Academic Search

VERY few photons need to be captured by the receptors of the human eye to excite a sensation of light. The number required is certainly no greater than 100 and may be much less1,2. A single rod requires only one photon to signal light3. A question which therefore arises is why do we not see punctate photon absorptions when we

John Ross; F. W. CAMPBELL

1978-01-01

328

Photon generator  

DOEpatents

A photon generator includes an electron gun for emitting an electron beam, a laser for emitting a laser beam, and an interaction ring wherein the laser beam repetitively collides with the electron beam for emitting a high energy photon beam therefrom in the exemplary form of x-rays. The interaction ring is a closed loop, sized and configured for circulating the electron beam with a period substantially equal to the period of the laser beam pulses for effecting repetitive collisions.

Srinivasan-Rao, Triveni (Shoreham, NY)

2002-01-01

329

Likelihood functions for the analysis of single-molecule binned photon sequences.  

PubMed

We consider the analysis of a class of experiments in which the number of photons in consecutive time intervals is recorded. Sequence of photon counts or, alternatively, of FRET efficiencies can be studied using likelihood-based methods. For a kinetic model of the conformational dynamics and state-dependent Poisson photon statistics, the formalism to calculate the exact likelihood that this model describes such sequences of photons or FRET efficiencies is developed. Explicit analytic expressions for the likelihood function for a two-state kinetic model are provided. The important special case when conformational dynamics are so slow that at most a single transition occurs in a time bin is considered. By making a series of approximations, we eventually recover the likelihood function used in hidden Markov models. In this way, not only is insight gained into the range of validity of this procedure, but also an improved likelihood function can be obtained. PMID:22711967

Gopich, Irina V

2012-03-01

330

Likelihood functions for the analysis of single-molecule binned photon sequences  

NASA Astrophysics Data System (ADS)

We consider the analysis of a class of experiments in which the number of photons in consecutive time intervals is recorded. Sequence of photon counts or, alternatively, of FRET efficiencies can be studied using likelihood-based methods. For a kinetic model of the conformational dynamics and state-dependent Poisson photon statistics, the formalism to calculate the exact likelihood that this model describes such sequences of photons or FRET efficiencies is developed. Explicit analytic expressions for the likelihood function for a two-state kinetic model are provided. The important special case when conformational dynamics are so slow that at most a single transition occurs in a time bin is considered. By making a series of approximations, we eventually recover the likelihood function used in hidden Markov models. In this way, not only is insight gained into the range of validity of this procedure, but also an improved likelihood function can be obtained.

Gopich, Irina V.

2012-03-01

331

Single-photon detection and its applications  

NASA Astrophysics Data System (ADS)

A single-photon detector is an extremely sensitive device capable of registering photons, offering essential technical support for optics quantum information applications. We review herein our recent experimental progress in the development and application of single-photon detection techniques. Techniques based on advanced self-differencing, low-pass filtering, frequency up-conversion and photon-number-resolving are introduced for attaining high-speed, high-efficiency, low-noise single-photon detection at infrared wavelengths. The advantages of high-speed single-photon detection are discussed in some applications, such as the laser ranging and quantum key distribution. The photon-number-resolving detection is shown to support efficient quantum random number generation.

Liang, Yan; Zeng, HePing

2014-07-01

332

Single-photon detection and its applications  

NASA Astrophysics Data System (ADS)

A single-photon detector is an extremely sensitive device capable of registering photons, offering essential technical support for optics quantum information applications. We review herein our recent experimental progress in the development and application of single-photon detection techniques. Techniques based on advanced self-differencing, low-pass filtering, frequency up-conversion and photon-number-resolving are introduced for attaining high-speed, high-efficiency, low-noise single-photon detection at infrared wavelengths. The advantages of high-speed single-photon detection are discussed in some applications, such as the laser ranging and quantum key distribution. The photon-number-resolving detection is shown to support efficient quantum random number generation.

Liang, Yan; Zeng, HePing

2014-04-01

333

Extending single-photon optimized superconducting transition edge sensors beyond the single-photon counting regime.  

PubMed

Typically, transition edge sensors resolve photon number of up to 10 or 20 photons, depending on the wavelength and TES design. We extend that dynamic range up to 1000 photons, while maintaining sub-shot noise detection process uncertainty of the number of detected photons and beyond that show a monotonic response up to ? 6 · 10(6) photons in a single light pulse. This mode of operation, which heats the sensor far beyond its transition edge into the normal conductive regime, offers a technique for connecting single-photon-counting measurements to radiant-power measurements at picowatt levels. Connecting these two usually incompatible operating regimes in a single detector offers significant potential for directly tying photon counting measurements to conventional cryogenic radiometric standards. In addition, our measurements highlight the advantages of a photon-number state source over a coherent pulse source as a tool for characterizing such a detector. PMID:23188345

Gerrits, Thomas; Calkins, Brice; Tomlin, Nathan; Lita, Adriana E; Migdall, Alan; Mirin, Richard; Nam, Sae Woo

2012-10-01

334

NON-Shor Factorization Via BEQS BEC: Watkins Number-Theory "Pure"-Mathematics U With Statistical-Physics; Benford Log-Law Inversion to ONLY BEQS digit d=0 BEC!!!  

NASA Astrophysics Data System (ADS)

Weiss-Page-Holthaus[Physica A,341,586(04); http://arxiv.org/abs/cond-mat/0403295] number-FACTORIZATION VIA BEQS BEC VS.(?) Shor-algorithm, strongly-supporting Watkins' [www.secamlocal.ex.ac.uk/people/staff/mrwatkin/] Intersection of number-theory "pure"-maths WITH (Statistical)-Physics, as Siegel[AMS Joint.Mtg.(02)-Abs.973-60-124] Benford logarithmic-law algebraic-INVERSION to ONLY BEQS with d=0 digit =oo gapFUL BEC!!! Siegel Riemann-hypothesis proof via Rayleigh[Phil.Trans.CLXI(1870)]-Polya[Math.Ann.(21)]-[Random-Walks & Electric-Nets., MAA(81)]-"Anderson"[PRL(58)]-localization-Siegel[Symp.Fractals,MRS Fall Mtg.(89)-5-papers!!!] FUZZYICS=CATEGORYICS: [LOCALITY]--MORPHISM/CROSSOVER/ AUTMATHCAT/DIM-CAT/ ANTONYM-->(GLOBALITY) FUNCTOR/SYNONYM/ concomitance to "noise"<=/Fluct.-Dissip. theorem/ FUNCTOR/SYNONYM/ equivalence/proportionality to => "generalized-susceptibility" power-spectrum [FLAT/FUNCTIONLESS/WHITE]--MORPHISM/ CROSSOVER/AUTMATHCAT/DIM-CAT/ANTONYM--> HYPERBOLICITY/ZIPF-law INEVITABILITY) intersection with ONLY BEQS BEC).

Lyons, M.; Carl-Ludwig Siegel, Edward

2011-03-01

335

A Photon Interference Detector with Continuous Display.  

ERIC Educational Resources Information Center

Describes an apparatus which attempts to give a direct visual impression of the random detection of individual photons coupled with the recognition of the classical intensity distribution as a result of fairly high proton statistics. (Author/GA)

Gilmore, R. S.

1978-01-01

336

Photon blockade in quadratically coupled optomechanical systems  

NASA Astrophysics Data System (ADS)

We study the steady-state photon statistics of a quadratically coupled optomechanical cavity, which is weakly driven by a monochromatic laser field. We examine the photon blockade by evaluating the second-order correlation function of the cavity photons. By restricting the system within the zero-, one-, and two-photon subspace, we obtain an approximate analytical expression for the correlation function. We also numerically investigate the correlation function by solving the quantum master equation including both optical and mechanical dissipations. The results show that, in the deep-resolved-sideband and single-photon strong-coupling regimes, the single-photon resonant driving will induce a photon blockade, which is limited by the thermal noise of the mechanical environment.

Liao, Jie-Qiao; Nori, Franco

2013-08-01

337

Vesicle Photonics  

SciTech Connect

Thin membranes, under appropriate boundary conditions, can self-assemble into vesicles, nanoscale bubbles that encapsulate and hence protect or transport molecular payloads. In this paper, we review the types and applications of light fields interacting with vesicles. By encapsulating light-emitting molecules (e.g. dyes, fluorescent proteins, or quantum dots), vesicles can act as particles and imaging agents. Vesicle imaging can take place also under second harmonic generation from vesicle membrane, as well as employing mass spectrometry. Light fields can also be employed to transport vesicles using optical tweezers (photon momentum) or directly pertrurbe the stability of vesicles and hence trigger the delivery of the encapsulated payload (photon energy).

Vasdekis, Andreas E.; Scott, E. A.; Roke, Sylvie; Hubbell, J. A.; Psaltis, D.

2013-04-03

338

Optimal pulse to generate non-classical photon states via photon blockade  

NASA Astrophysics Data System (ADS)

The single photon character of nonclassical states of light that can be generated using photon blockade is analyzed for time domain operation. We show that improved single photon statistics (single photon around 85% with a multi-photon of 8%) can be obtained by adequately choosing the parameters (mainly amplitude and pulseduration) of the driving laser pulses. An alternative method, where the system is driven via a continuous wave laser and the frequency of the dipole is controlled (e.g. electrically) at very fast timescales is presented. We also show that this non-classical state performs better than a weak coherent pulse, when applied to BB84 quantum cryptography protocol.

Majumdar, Arka; Faraon, Andrei; Vuckovic, Jelena

2010-02-01

339

Third-order antibunching from an imperfect single-photon source.  

PubMed

We measure second- and third-order temporal coherences, g((2))(?) and g((3))(?1,?2), of an optically excited single-photon source: an InGaAs quantum dot in a microcavity pedestal. Increasing the optical excitation power leads to an increase in the measured count rate, and also an increase in multi-photon emission probability. We show that standard measurements of g((2)) provide limited information about this multi-photon probability, and that more information can be gained by simultaneously measuring g((3)). Experimental results are compared with a simple theoretical model to show that the observed antibunchings are consistent with an incoherent addition of two sources: 1) an ideal single-photon source that never emits multiple photons and 2) a background cavity emission having Poissonian photon number statistics. Spectrally resolved cross-correlation measurements between quantum-dot and cavity modes show that photons from these two sources are largely uncorrelated, further supporting the model. We also analyze the Hanbury Brown-Twiss interferometer implemented with two or three "click" detectors, and explore the conditions under which it can be used to accurately measure g((2))(?) and g((3))(?1,?2). PMID:24663616

Stevens, Martin J; Glancy, Scott; Nam, Sae Woo; Mirin, Richard P

2014-02-10

340

Single-Photon-Sensitive HgCdTe Avalanche Photodiode Detector  

NASA Technical Reports Server (NTRS)

The purpose of this program was to develop single-photon-sensitive short-wavelength infrared (SWIR) and mid-wavelength infrared (MWIR) avalanche photodiode (APD) receivers based on linear-mode HgCdTe APDs, for application by NASA in light detection and ranging (lidar) sensors. Linear-mode photon-counting APDs are desired for lidar because they have a shorter pixel dead time than Geiger APDs, and can detect sequential pulse returns from multiple objects that are closely spaced in range. Linear-mode APDs can also measure photon number, which Geiger APDs cannot, adding an extra dimension to lidar scene data for multi-photon returns. High-gain APDs with low multiplication noise are required for efficient linear-mode detection of single photons because of APD gain statistics -- a low-excess-noise APD will generate detectible current pulses from single photon input at a much higher rate of occurrence than will a noisy APD operated at the same average gain. MWIR and LWIR electron-avalanche HgCdTe APDs have been shown to operate in linear mode at high average avalanche gain (M > 1000) without excess multiplication noise (F = 1), and are therefore very good candidates for linear-mode photon counting. However, detectors fashioned from these narrow-bandgap alloys require aggressive cooling to control thermal dark current. Wider-bandgap SWIR HgCdTe APDs were investigated in this program as a strategy to reduce detector cooling requirements.

Huntington, Andrew

2013-01-01

341

Photonic Floquet topological insulators.  

PubMed

Topological insulators are a new phase of matter, with the striking property that conduction of electrons occurs only on their surfaces. In two dimensions, electrons on the surface of a topological insulator are not scattered despite defects and disorder, providing robustness akin to that of superconductors. Topological insulators are predicted to have wide-ranging applications in fault-tolerant quantum computing and spintronics. Substantial effort has been directed towards realizing topological insulators for electromagnetic waves. One-dimensional systems with topological edge states have been demonstrated, but these states are zero-dimensional and therefore exhibit no transport properties. Topological protection of microwaves has been observed using a mechanism similar to the quantum Hall effect, by placing a gyromagnetic photonic crystal in an external magnetic field. But because magnetic effects are very weak at optical frequencies, realizing photonic topological insulators with scatter-free edge states requires a fundamentally different mechanism-one that is free of magnetic fields. A number of proposals for photonic topological transport have been put forward recently. One suggested temporal modulation of a photonic crystal, thus breaking time-reversal symmetry and inducing one-way edge states. This is in the spirit of the proposed Floquet topological insulators, in which temporal variations in solid-state systems induce topological edge states. Here we propose and experimentally demonstrate a photonic topological insulator free of external fields and with scatter-free edge transport-a photonic lattice exhibiting topologically protected transport of visible light on the lattice edges. Our system is composed of an array of evanescently coupled helical waveguides arranged in a graphene-like honeycomb lattice. Paraxial diffraction of light is described by a Schrödinger equation where the propagation coordinate (z) acts as 'time'. Thus the helicity of the waveguides breaks z-reversal symmetry as proposed for Floquet topological insulators. This structure results in one-way edge states that are topologically protected from scattering. PMID:23579677

Rechtsman, Mikael C; Zeuner, Julia M; Plotnik, Yonatan; Lumer, Yaakov; Podolsky, Daniel; Dreisow, Felix; Nolte, Stefan; Segev, Mordechai; Szameit, Alexander

2013-04-11

342

Histoplasmosis Statistics  

MedlinePLUS

... Añadir en... Favorites Delicious Digg Google Bookmarks Histoplasmosis Statistics Between 50% and 80% of people who live ... Prevention Sources Diagnosis & Testing Treatment & Outcomes Health Professionals Statistics Additional Information Blastomycosis Definition Symptoms People at Risk & ...

343

Caregiving Statistics  

MedlinePLUS

Statistics on Family Caregivers and Family Caregiving Caregiving Population Economics of Caregiving Impact on Family Caregiver's Health ... Identified Family Caregivers, 2001. Top State by State Statistics The economic value of family caregiving is detailed ...

344

Mathematical Statistics.  

National Technical Information Service (NTIS)

The areas of research included were graph theory, error-correcting codes, information retrieval, large-sample statistical tests, design of experiments, asymptotic behavior of linear rank statistics, approximation theory, nonparametric tests, fitting frequ...

N. L. Johnson

1973-01-01

345

Deterministic production of N-photon states from a single atom-cavity system  

NASA Astrophysics Data System (ADS)

We propose a mechanism for producing N-photon states on demand leaking from a single-mode optical cavity interacting with a single atom and a laser pulse. The number of photons can be chosen because it is determined by the Zeeman substructure of the ground state of the atom and its initial state. The deterministic generation of traveling light of 1?n?2F photons is achieved, when a circularly polarized laser pulse completely transfers the atomic population between Zeeman sublevels of the ground hyperfine state F through far-detuned Raman scattering, thus producing linearly polarized cavity photons. We describe analytically the evolution of optical field taking into account the spontaneous losses and the cavity damping. We analyze the photon statistics showing that it is close to Poissonian light. We show also that this technique provides a deterministic source of a train of identical multiphoton states with a definite number of photons if a sequence of left- and right-circularly polarized laser pulses is applied. The scheme expands the possibilities for using complex internal states of light to transmit data.

Gogyan, A.; Guérin, S.; Leroy, C.; Malakyan, Yu.

2012-12-01

346

Descriptive statistics.  

PubMed

In this article, we introduced basic concepts of statistics, type of distributions, and descriptive statistics. A few examples were also provided. The basic concepts presented herein are only a fraction of the concepts related to descriptive statistics. Also, there are many commonly used distributions not presented herein, such as Poisson distributions for rare events and exponential distributions, F distributions, and logistic distributions. More information can be found in many statistics books and publications. PMID:19891281

Shi, Runhua; McLarty, Jerry W

2009-10-01

347

Photon-photon collisions via relativisitic mirrors  

SciTech Connect

Photon-photon scattering at low energies has been predicted theoretically for many years. However, due to the extremely small cross section there has been no experimental confirmation of this. Due to the rapid increase in laser irradiances and projected peak irradiances in planned facilities regimes could be reached where photon-photon scattering could be experimentally observed. We will first review basic aspects of photon-photon collisions concentrating on the calculation of the photon-photon scattering cross section. Then we will discuss the possibilities for observing these phenomena in ultra-high irradiance laser-plasma interactions involving relativistic mirrors.

Koga, James K. [Quantum Beam Science Directorate, Japan Atomic Energy Agency, Kizugawa, Kyoto 619-0215 (Japan)

2012-07-11

348

Statistical Diversions  

ERIC Educational Resources Information Center

As a branch of knowledge, Statistics is ubiquitous and its applications can be found in (almost) every field of human endeavour. In this article, the authors track down the possible source of the link between the "Siren song" and applications of Statistics. Answers to their previous five questions and five new questions on Statistics are presented.

Petocz, Peter; Sowey, Eric

2008-01-01

349

Health Statistics.  

ERIC Educational Resources Information Center

Overview of federal collection of health statistics highlights federal budgets; the National Center for Health Statistics (role, periodicity report); vital statistics (surveys of physicians, hospitals, nursing homes); household surveys (National Health Interview Survey); and proposed reorganization of the Office of the Assistant Secretary of…

Melnick, Daniel; Huckabee, David

1983-01-01

350

Statistical Diversions  

ERIC Educational Resources Information Center

The term "data snooping" refers to the practice of choosing which statistical analyses to apply to a set of data after having first looked at those data. Data snooping contradicts a fundamental precept of applied statistics, that the scheme of analysis is to be planned in advance. In this column, the authors shall elucidate the statistical

Petocz, Peter; Sowey, Eric

2012-01-01

351

Measuring Temporal Photon Bunching in Blackbody Radiation  

NASA Astrophysics Data System (ADS)

Light from thermal blackbody radiators such as stars exhibits photon bunching behavior at sufficiently short timescales. However, with available detector bandwidths, this bunching signal is difficult to observe directly. We present an experimental technique to increase the photon bunching signal in blackbody radiation via spectral filtering of the light source. Our measurements reveal strong temporal photon bunching from blackbody radiation, including the Sun. This technique allows for an absolute measurement of the photon bunching signature g (2)(0), and thereby a direct statement on the statistical nature of a light source. Such filtering techniques may help revive the interest in intensity interferometry as a tool in astronomy.

Tan, P. K.; Yeo, G. H.; Poh, H. S.; Chan, A. H.; Kurtsiefer, C.

2014-07-01

352

Statistics Canada = Statistique Canada  

NSDL National Science Digital Library

Statistics Canada, a national statistical agency, offers this excellent collection on the economic and social conditions in Canada. Statistical information is divided into four broad topics: The Land, The People, The Economy, and the State. Within each are a number of sub-topics which offer lists of statistical tables. Newly released data, research papers, downloadable publications (Adobe Acrobat [.pdf] format only), and notices of seminars and conferences are featured in addition to The Daily, a collection of the latest news releases and publications from the agency. This site can be viewed in English or French. Note that there is a combination of free and fee based material available.

1997-01-01

353

Number Track  

NSDL National Science Digital Library

Students can use this interactive Flash applet to practice ordering whole numbers within 20. The applet displays a track and number tiles, which the user drags to create the correct sequence of numbers 1 through 20. Users may choose from four levels: place 5 missing numbers, place 10 numbers, arrange all 20 numbers, or create your own challenge.

Bunker, Dan

2010-01-01

354

Polarization-entangled light pulses of 10(5) photons.  

PubMed

We experimentally demonstrate polarization entanglement for squeezed vacuum pulses containing more than 10(5) photons. We also study photon-number entanglement by calculating the Schmidt number and measuring its operational counterpart. Theoretically, our pulses are the more entangled the brighter they are. This promises important applications in quantum technologies, especially photonic quantum gates and quantum memories. PMID:23102288

Iskhakov, Timur Sh; Agafonov, Ivan N; Chekhova, Maria V; Leuchs, Gerd

2012-10-12

355

The 'Pile-up Effect' in Photon Detection  

SciTech Connect

We quantify the pile-up of X-ray photons in a single-photon-counting detector with finite dead-time when subject to an intense synchrotron beam of non-Poisson distributed photons. The pile-up leads to a non-linearity between the registered count-rate and the true photon-rate when a single-channel analyzer is employed and we show that the phenomenon can be described by use of a simple statistical model.

Madsen, A.; Zontone, F.; Gruebel, G. [European Synchrotron Radiation Facility, B. P. 220, F-38043 Grenoble (France); Als-Nielsen, J. [Niels Bohr Institute, Orsted Laboratory, DK-2100 Copenhagen O (Denmark)

2004-05-12

356

Number Sense  

NSDL National Science Digital Library

Hacker has given you a challenge. Heâll run his number machine to create a number. Then youâll get three numbers between one and nine. The challenge is to make a number that is larger than the one on Hackerâs machine. Be careful though--Hacker will give you numbers that canât be bigger than his!

2008-01-01

357

Di-photon and photon + b/c production cross sections at Ecm = 1.96- TeV  

SciTech Connect

Measurements of the di-photon cross section have been made in the central region and are found to be in good agreement with NLO QCD predictions. The cross section of events containing a photon and additional heavy flavor jet have also been measured, as well as the ratio of photon + b to photon + c. The statistically limited sample shows good agreement with Leading Order predictions.

Gajjar, Anant; /Liverpool U.

2005-05-01

358

Number Line  

NSDL National Science Digital Library

This iOS app helps students to visualize number sentences and create models for addition, subtractions, multiplication, and division. The number line can be adjusted to represent multiples of numbers from one to one hundred.

Clarity Innovations, Inc.

2013-11-22

359

Story Numbers.  

ERIC Educational Resources Information Center

A concrete approach to prime numbers is presented using rectangles and triangles to construct a building for each number so that each story represents a pair of factors and the triangular-shaped roof represents the number. (MP)

Swafford, Jane; McGinty, Robert

1978-01-01

360

Integrated spatial multiplexing of heralded single-photon sources  

PubMed Central

The non-deterministic nature of photon sources is a key limitation for single-photon quantum processors. Spatial multiplexing overcomes this by enhancing the heralded single-photon yield without enhancing the output noise. Here the intrinsic statistical limit of an individual source is surpassed by spatially multiplexing two monolithic silicon-based correlated photon pair sources in the telecommunications band, demonstrating a 62.4% increase in the heralded single-photon output without an increase in unwanted multipair generation. We further demonstrate the scalability of this scheme by multiplexing photons generated in two waveguides pumped via an integrated coupler with a 63.1% increase in the heralded photon rate. This demonstration paves the way for a scalable architecture for multiplexing many photon sources in a compact integrated platform and achieving efficient two-photon interference, required at the core of optical quantum computing and quantum communication protocols.

Collins, M.J.; Xiong, C.; Rey, I.H.; Vo, T.D.; He, J.; Shahnia, S.; Reardon, C.; Krauss, T.F.; Steel, M.J.; Clark, A.S.; Eggleton, B.J.

2013-01-01

361

Photonic Nanojets  

PubMed Central

This paper reviews the substantial body of literature emerging since 2004 concerning photonic nanojets. The photonic nanojet is a narrow, high-intensity, non-evanescent light beam that can propagate over a distance longer than the wavelength ? after emerging from the shadow-side surface of an illuminated lossless dielectric microcylinder or microsphere of diameter larger than ?. The nanojet’s minimum beamwidth can be smaller than the classical diffraction limit, in fact as small as ~?/3 for microspheres. It is a nonresonant phenomenon appearing for a wide range of diameters of the microcylinder or microsphere if the refractive index contrast relative to the background is less than about 2:1. Importantly, inserting within a nanojet a nanoparticle of diameter d? perturbs the far-field backscattered power of the illuminated microsphere by an amount that varies as d?3 for a fixed ?. This perturbation is much slower than the d?6 dependence of Rayleigh scattering for the same nanoparticle, if isolated. This leads to a situation where, for example, the measured far-field backscattered power of a 3-?m diameter microsphere could double if a 30-nm diameter nanoparticle were inserted into the nanojet emerging from the microsphere, despite the nanoparticle having only 1/10,000th the cross-section area of the microsphere. In effect, the nanojet serves to project the presence of the nanoparticle to the far field. These properties combine to afford potentially important applications of photonic nanojets for detecting and manipulating nanoscale objects, subdiffraction-resolution nanopatterning and nanolithography, low-loss waveguiding, and ultrahigh-density optical storage.

Heifetz, Alexander; Kong, Soon-Cheol; Sahakian, Alan V.; Taflove, Allen; Backman, Vadim

2009-01-01

362

Statistics Manual.  

ERIC Educational Resources Information Center

This guide outlines an Option Y course, which has seven learner objectives geared to providing students with an introduction to the concerns and methods of statistics and equipping pupils to deal with the many statistical matters of importance in society. Topics included in the course are graphs and charts, collection and organization of data,…

Singer, Arlene; And Others

363

Statistics Anxiety and Business Statistics: The International Student  

ERIC Educational Resources Information Center

Does the international student suffer from statistics anxiety? To investigate this, the Statistics Anxiety Rating Scale (STARS) was administered to sixty-six beginning statistics students, including twelve international students and fifty-four domestic students. Due to the small number of international students, nonparametric methods were used to…

Bell, James A.

2008-01-01

364

Using High-Power Lasers for Detection of Elastic Photon-Photon Scattering  

NASA Astrophysics Data System (ADS)

The properties of four-wave interaction via the nonlinear quantum vacuum is investigated. The effect of the quantum vacuum is to generate photons with new frequencies and wave vectors, due to elastic photon-photon scattering. An expression for the number of generated photons is derived, and using state-of-the-art laser data it is found that the number of photons can reach detectable levels. In particular, the prospect of using the high-repetition Astra Gemini system at the Rutherford Appleton Laboratory is discussed. The problem of noise sources is reviewed, and it is found that the noise level can be reduced well below the signal level. Thus, detection of elastic photon-photon scattering may for the first time be achieved.

Lundström, E.; Brodin, G.; Lundin, J.; Marklund, M.; Bingham, R.; Collier, J.; Mendonça, J. T.; Norreys, P.

2006-03-01

365

Using high-power lasers for detection of elastic photon-photon scattering.  

PubMed

The properties of four-wave interaction via the nonlinear quantum vacuum is investigated. The effect of the quantum vacuum is to generate photons with new frequencies and wave vectors, due to elastic photon-photon scattering. An expression for the number of generated photons is derived, and using state-of-the-art laser data it is found that the number of photons can reach detectable levels. In particular, the prospect of using the high-repetition Astra Gemini system at the Rutherford Appleton Laboratory is discussed. The problem of noise sources is reviewed, and it is found that the noise level can be reduced well below the signal level. Thus, detection of elastic photon-photon scattering may for the first time be achieved. PMID:16606179

Lundström, E; Brodin, G; Lundin, J; Marklund, M; Bingham, R; Collier, J; Mendonça, J T; Norreys, P

2006-03-01

366

40 CFR 1065.602 - Statistics.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Statistics. 1065.602 ...Calculations and Data Requirements § 1065.602 Statistics. (a) Overview...Determine if your data passes a t -test...calculate the t statistic and its number...

2010-07-01

367

40 CFR 1065.602 - Statistics.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Statistics. 1065.602 ...Calculations and Data Requirements § 1065.602 Statistics. (a) Overview...Determine if your data passes a t -test...calculate the t statistic and its number...

2009-07-01

368

Maximum likelihood-based analysis of single-molecule photon arrival trajectories  

NASA Astrophysics Data System (ADS)

In this work we explore the statistical properties of the maximum likelihood-based analysis of one-color photon arrival trajectories. This approach does not involve binning and, therefore, all of the information contained in an observed photon strajectory is used. We study the accuracy and precision of parameter estimates and the efficiency of the Akaike information criterion and the Bayesian information criterion (BIC) in selecting the true kinetic model. We focus on the low excitation regime where photon trajectories can be modeled as realizations of Markov modulated Poisson processes. The number of observed photons is the key parameter in determining model selection and parameter estimation. For example, the BIC can select the true three-state model from competing two-, three-, and four-state kinetic models even for relatively short trajectories made up of 2 × 103 photons. When the intensity levels are well-separated and 104 photons are observed, the two-state model parameters can be estimated with about 10% precision and those for a three-state model with about 20% precision.

Hajdziona, Marta; Molski, Andrzej

2011-02-01

369

Number Flash  

NSDL National Science Digital Library

This iOS app helps students make the transition from counting to number recognition by thinking of a number of objects in relation to five and ten. The app displays a set number of items from one to twenty in ten frames then flashes away after the preset number of seconds. The user must identify the number that was shown on the ten frames.

Mark, Mitchell

2013-03-10

370

Photonics & nanotechnology  

NASA Astrophysics Data System (ADS)

Capacitance-voltage characteristics of InN quantum dots in AlGaN/GaN heterostructure / A. Asgari & M. Afshari Bavili -- A comparison of different coherent deep ultraviolet generations using second harmonic generation with the blue laser diode excitation / C. Tangtrongbenjasil & K. Konaka -- Application of reflection-spectrum envelope for sampled gratings / X. He ... [et al.] -- Temperature-dependent photoluminescence investigation of narrow well-width InGaAs/InP single quantum well / W. Pecharapa ... [et al.] -- Shooting method calculation of temperature dependence of transition energy for quantum well structure / B. Jukgoljun, W. Pecharapa and W. Techitdheera -- Design of optical ring resonator filters for WDM applications / P. Saeung & P. P. Yupapin -- Chaotic signal filtering device using the series waveguide micro ring resonator / P. P. Yupapin ... [et al.] -- An alternative optical switch using Mach Zehnder interferometer and two ring resonators / P. P. Yupapin, P. Saeung and P. Chunpang -- Entangled photons generation and regeneration using a nonlinear fiber ring resonator / S. Suchat, W. Khunnan and P. P. Yupapin -- Nonlinear effects in fiber grating to nano-scale measurement resolution / P. Phipithirankarn, P. Yabosdee and P. P. Yupapin -- Quantum chaotic signals generation by a nonlinear micro ring resonator / C. Sripakdee, W. Suwancharoen and P. P. Yupapin -- Investigation of photonic devices pigtailing using laser welding / M. M. A. Fadhali -- A soliton pulse in a nonlinear micro ring resonator system: unexpected results and applications / P. P. Yupapin, S. Pipatsart and N. Pornsuwancharoen.

Yupapin, Preecha; Saeung, Prajak

2008-11-01

371

Statistical topological insulators  

NASA Astrophysics Data System (ADS)

We define a class of insulators with gapless surface states protected from localization due to the statistical properties of a disordered ensemble, namely, due to the ensemble's invariance under a certain symmetry. We show that these insulators are topological, and are protected by a Z2 invariant. Finally, we prove that every topological insulator gives rise to an infinite number of classes of statistical topological insulators in higher dimensions. Our conclusions are confirmed by numerical simulations.

Fulga, I. C.; van Heck, B.; Edge, J. M.; Akhmerov, A. R.

2014-04-01

372

Statistics Clinic  

NASA Technical Reports Server (NTRS)

Do you have elevated p-values? Is the data analysis process getting you down? Do you experience anxiety when you need to respond to criticism of statistical methods in your manuscript? You may be suffering from Insufficient Statistical Support Syndrome (ISSS). For symptomatic relief of ISSS, come for a free consultation with JSC biostatisticians at our help desk during the poster sessions at the HRP Investigators Workshop. Get answers to common questions about sample size, missing data, multiple testing, when to trust the results of your analyses and more. Side effects may include sudden loss of statistics anxiety, improved interpretation of your data, and increased confidence in your results.

Feiveson, Alan H.; Foy, Millennia; Ploutz-Snyder, Robert; Fiedler, James

2014-01-01

373

Collaborative Statistics  

NSDL National Science Digital Library

Collaborative Statistics was written by Barbara Illowsky and Susan Dean, faculty members at De Anza College in Cupertino, California. The textbook was developed over several years and has been used in regular and honors-level classroom settings and in distance learning classes. This textbook is intended for introductory statistics courses being taken by students at twoâ and fourâÂÂyear colleges who are majoring in fields other than math or engineering. Intermediate algebra is the only prerequisite. The book focuses on applications of statistical knowledge rather than the theory behind it.

Dean, Susan; Illowsky, Barbara

2009-11-17

374

Nifty Numbers!  

NSDL National Science Digital Library

You will be working with numbers in all sorts of ways. First, you will play cop by picking numbers based on their divisibility. Then you will be adding and subtracting fractions in two fun and exciting games. First, as a cop, you will catch numbers that are divisible by which ever number you pick, avoinding crashing into non-divisible numbers. Number Cop-Divisibility Now, play Fishy Fractions! and help feed the seagull by practicing adding fractions. Make sure you read the instructions before getting started! Make sure to simplify your answers! After you ...

Miss.cochran

2008-03-26

375

Mathematical Statistics  

NSDL National Science Digital Library

Created by Richard Dudley of the Massachusetts Institute of Technology, this lesson, Mathematical Statistics, is a graduate-level course featuring book chapters and sections presented as lecture notes, problem sets, exams, and a description for an optional term-paper. The course covers: decision theory, estimation, confidence intervals, hypothesis testing, asymptotic efficiency of estimates, exponential families, sequential analysis, and large sample theory. This is a comprehensive overview of this upper level statistics course.

Dudley, Richard

2009-01-29

376

Statistical Mechanics  

Microsoft Academic Search

We review and further develop a mathematical framework for non-equilibrium quantum statistical mechanics recently proposed in (JP4, JP5, JP6, Ru3, Ru4, Ru5, Ru6). In the alge- braic formalism of quantum statistical mechanics we introduce notions of non-equilibrium steady states, entropy production and heat fluxes, and study their properties. Our basic paradigm is a model of a small (finite) quantum system

V. Jaksi ´; C.-A. Pillet

1937-01-01

377

Tooth Numbering  

MedlinePLUS

... numbered as well. Illustrations created by Simple Steps designer Michael Becker Universal Numbering System Adults In this ... indicates that it is a deciduous (primary or "baby") tooth. So, a child's first tooth on the ...

378

Lithography system using quantum entangled photons  

NASA Technical Reports Server (NTRS)

A system of etching using quantum entangled particles to get shorter interference fringes. An interferometer is used to obtain an interference fringe. N entangled photons are input to the interferometer. This reduces the distance between interference fringes by n, where again n is the number of entangled photons.

Williams, Colin (Inventor); Dowling, Jonathan (Inventor); della Rossa, Giovanni (Inventor)

2002-01-01

379

Transient photon production in a QGP  

SciTech Connect

We discuss the shortcomings of a formula that has been used in the literature to compute the number of photons emitted by a hot or dense system during a finite time, and show that the transient effects it predicts for the photon rate are unphysical.

Fraga, Eduardo S. [Intituto de Fisica, Universidade Federal do Rio de Janeiro, C.P. 68528, Rio de Janeiro, RJ 21941-972 (Brazil); Gelis, Francois [Service de Physique Theorique, CEA/DSM/Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette cedex (France); Schiff, Dominique [Laboratoire de Physique Theorique, Bat. 210, Universite Paris XI, 91405 Orsay cedex (France)

2004-12-02

380

Thermal noise and correlations in photon detection  

Microsoft Academic Search

The standard expressions for the noise that is due to photon fluctuations in thermal background radiation typically apply only for a single detector and are often strictly valid only for single-mode illumination. I describe a technique for rigorously calculating thermal photon noise, which allows for arbitrary numbers of optical inputs and detectors, multiple-mode illumination, and both internal and external noise

Jonas Zmuidzinas

2003-01-01

381

Disordered photonics  

NASA Astrophysics Data System (ADS)

What do lotus flowers have in common with human bones, liquid crystals with colloidal suspensions, and white beetles with the beautiful stones of the Taj Mahal? The answer is they all feature disordered structures that strongly scatter light, in which light waves entering the material are scattered several times before exiting in random directions. These randomly distributed rays interfere with each other, leading to interesting, and sometimes unexpected, physical phenomena. This Review describes the physics behind the optical properties of disordered structures and how knowledge of multiple light scattering can be used to develop new applications. The field of disordered photonics has grown immensely over the past decade, ranging from investigations into fundamental topics such as Anderson localization and other transport phenomena, to applications in imaging, random lasing and solar energy.

Wiersma, Diederik S.

2013-03-01

382

Negative Numbers  

NSDL National Science Digital Library

This article is an account of how negative numbers became part of the "vocabulary" of mathematicians and of some of the earliest appearances of negative numbers in calculations of the ancient civilizations of China, India and Greece. Although negative numbers were used in calculations, negative answers to mathematical problems were considered meaningless or impossible. The troubled history of negative numbers presented in this article shows how the simple mathematical principles taken for granted today have taken thousands of years to develop.

Howard, Jill

2009-05-01

383

Resonance formation in photon-photon collisions  

SciTech Connect

Recent experimental progress on resonance formation in photon-photon collisions is reviewed with particular emphasis on the pseudoscalar and tensor nonents and on the ..gamma gamma..* production of spin-one resonances. 37 refs., 17 figs., 5 tabs.

Gidal, G.

1988-08-01

384

General displaced SU(1, 1) number states: Revisited  

NASA Astrophysics Data System (ADS)

The most general displaced number states, based on the bosonic and an irreducible representation of the Lie algebra symmetry of su(1, 1) and associated with the Calogero-Sutherland model are introduced. Here, we utilize the Barut-Girardello displacement operator instead of the Klauder-Perelomov counterpart, to construct new kind of the displaced number states which can be classified in nonlinear coherent states regime, too, with special nonlinearity functions. They depend on two parameters, and can be converted into the well-known Barut-Girardello coherent and number states, respectively, depending on which of the parameters equal to zero. A discussion of the statistical properties of these states is included. Significant are their squeezing properties and anti-bunching effects which can be raised by increasing the energy quantum number. Depending on the particular choice of the parameters of the above scenario, we are able to determine the status of compliance with flexible statistics. Major parts of the issue is spent on something that these states, in fact, should be considered as new kind of photon-added coherent states, too. Which can be reproduced through an iterated action of a creation operator on new nonlinear Barut-Girardello coherent states. Where the latter carry, also, outstanding statistical features.

Dehghani, A.

2014-04-01

385

Number Balance  

NSDL National Science Digital Library

This open-ended interactive Flash applet helps students develop operation and number sense, facility with number facts, and understanding of equations. Users designate single-digit whole numbers or integers and operations on both sides of an equation and test for balance. Users can enter numbers by using the keyboard or arrow buttons or by dragging number tiles. Each element can be hidden and a seesaw may be toggled on/off. Teachers may use this applet to lead instruction, or students may use it independently to perform specific investigations or explore freely. Supplementary documents include Objectives, containing teaching suggestions, and a student recording sheet.

Bunker, Dan

2005-01-01

386

Single photon searches at PEP  

SciTech Connect

The MAC and ASP searches for events with a single photon and no other observed particles are reviewed. New results on the number of neutrino generations and limits on selection, photino, squark and gluino masses from the ASP experiment are presented.

Hollebeek, R.

1985-12-01

387

Spectra of Photon Down Conversion  

SciTech Connect

We demonstrate that quasi-exactly solvable models of quantum mechanics can be used in nonlinear optical processes for a down conversion or second-harmonic generation processes. After the reduction we use the Turbiner and Bender -Dunne polynomial approach. The eigenvalues of Hamiltonian for low number of photons are calculated and the approximation formula is found out.

Smotlacha, J.; Chadzitaskos, G. [Department of Physics, Faculty of Nuclear and Physical Engineering, Czech Technical University, Brehova 7, CZ-115 19, Prague (Czech Republic); Daskaloyannis, C. [Department of Mathematics, University of Thessaloniki, GR-541 24 Thessaloniki (Greece)

2009-11-30

388

Nanophotonic technologies for single-photon devices  

NASA Astrophysics Data System (ADS)

The progress in nanofabrication has made possible the realization of optic nanodevices able to handle single photons and to exploit the quantum nature of single-photon states. In particular, quantum cryptography (or more precisely quantum key distribution, QKD) allows unconditionally secure exchange of cryptographic keys by the transmission of optical pulses each containing no more than one photon. Additionally, the coherent control of excitonic and photonic qubits is a major step forward in the field of solid-state cavity quantum electrodynamics, with potential applications in quantum computing. Here, we describe devices for realization of single photon generation and detection based on high resolution technologies and their physical properties. Particular attention will be devoted to the description of single-quantum dot sources based on photonic crystal microcavites optically and electrically driven: the electrically driven devices is an important result towards the realization of single photon source “on demand”. A new class of single photon detectors, based on superconducting nanowires, the superconducting single-photon detectors (SSPDs) are also introduced: the fabrication techniques and the design proposed to obtain large area coverage and photon number-resolving capability are described.

Gerardino, A.; Francardi, M.; Gaggero, A.; Mattioli, F.; Leoni, R.; Balet, L.; Chauvin, N.; Marsili, F.; Fiore, A.

2010-12-01

389

Light scattering from ultracold atoms in optical lattices as an optical probe of quantum statistics  

SciTech Connect

We study off-resonant collective light scattering from ultracold atoms trapped in an optical lattice. Scattering from different atomic quantum states creates different quantum states of the scattered light, which can be distinguished by measurements of the spatial intensity distribution, quadrature variances, photon statistics, or spectral measurements. In particular, angle-resolved intensity measurements reflect global statistics of atoms (total number of radiating atoms) as well as local statistical quantities (single-site statistics even without optical access to a single site) and pair correlations between different sites. As a striking example we consider scattering from transversally illuminated atoms into an optical cavity mode. For the Mott-insulator state, similar to classical diffraction, the number of photons scattered into a cavity is zero due to destructive interference, while for the superfluid state it is nonzero and proportional to the number of atoms. Moreover, we demonstrate that light scattering into a standing-wave cavity has a nontrivial angle dependence, including the appearance of narrow features at angles, where classical diffraction predicts zero. The measurement procedure corresponds to the quantum nondemolition measurement of various atomic variables by observing light.

Mekhov, Igor B. [Institut fuer Theoretische Physik, Universitaet Innsbruck, Innsbruck (Austria); Faculty of Physics, St. Petersburg State University, St. Petersburg (Russian Federation); Maschler, Christoph; Ritsch, Helmut [Institut fuer Theoretische Physik, Universitaet Innsbruck, Innsbruck (Austria)

2007-11-15

390

Random numbers for simulation  

Microsoft Academic Search

In the mind of the average computer user, the problem of generating uniform variates by computer has been solved long ago. After all, every computer :system offers one or more function(s) to do so. Many software products, like compilers, spreadsheets, statistical or numerical packages, etc. also offer their own. These functions supposedly return numbers that could be used, for all

Pierre L'Ecuyer

1990-01-01

391

Calculating statistical distributions from operator relations: The statistical distributions of various intermediate statistics  

SciTech Connect

In this paper, we give a general discussion on the calculation of the statistical distribution from a given operator relation of creation, annihilation, and number operators. Our result shows that as long as the relation between the number operator and the creation and annihilation operators can be expressed as a{sup †}b=?(N) or N=?{sup ?1}(a{sup †}b), where N, a{sup †}, and b denote the number, creation, and annihilation operators, i.e., N is a function of quadratic product of the creation and annihilation operators, the corresponding statistical distribution is the Gentile distribution, a statistical distribution in which the maximum occupation number is an arbitrary integer. As examples, we discuss the statistical distributions corresponding to various operator relations. In particular, besides the Bose–Einstein and Fermi–Dirac cases, we discuss the statistical distributions for various schemes of intermediate statistics, especially various q-deformation schemes. Our result shows that the statistical distributions corresponding to various q-deformation schemes are various Gentile distributions with different maximum occupation numbers which are determined by the deformation parameter q. This result shows that the results given in much literature on the q-deformation distribution are inaccurate or incomplete. -- Highlights: ? A general discussion on calculating statistical distribution from relations of creation, annihilation, and number operators. ? A systemic study on the statistical distributions corresponding to various q-deformation schemes. ? Arguing that many results of q-deformation distributions in literature are inaccurate or incomplete.

Dai, Wu-Sheng, E-mail: daiwusheng@tju.edu.cn; Xie, Mi, E-mail: xiemi@tju.edu.cn

2013-05-15

392

Oral Health Status and Access to Oral Health Care for U.S. Adults Aged 18-64: National Health Interview Survey, 2008. Vital and Health Statistics Series 10, Number 253.  

National Technical Information Service (NTIS)

This report presents statistics from the 2008 National Health Interview Survey (NHIS) on selected measures of oral health status and oral health care access for adults aged 18-64. Estimates are presented by sex, age, race and ethnicity, nativity, educatio...

2012-01-01

393

Library Research and Statistics. Research on Libraries and Librarianship in 2002; Number of Libraries in the United States and Canada; Highlights of NCES Surveys; Library Acquisition Expenditures, 2001-2002: U.S. Public, Academic, Special, and Government Libraries; LJ Budget Report: A Precarious Holding Pattern; Price Indexes for Public and Academic Libraries; Library Buildings 2002: The Building Buck Doesn't Stop Here.  

ERIC Educational Resources Information Center

Includes seven reports that discuss research on libraries and librarianship, including academic, public, and school libraries; awards and grants; number of libraries in the United States and Canada; National Center for Education Statistics results; library expenditures for public, academic, special, and government libraries; library budgets; price…

Lynch, Mary Jo; Oder, Norman; Halstead, Kent; Fox, Bette-Lee

2003-01-01

394

Number Grids and Number Triangles  

NSDL National Science Digital Library

Practice counting, counting by tens, place value, and fact families by entering your answers into the blank boxes; click the big blue and green buttons to check your work. Each of the five levels of Number Grid activities displays a section of a matrix containing a set of of consecutive whole numbers. A move from one number to the next within a row corresponds to a change of one; a move from one number to the next within a column refers to a change of ten. The three levels of Number Triangle activities provide practice with fact families and inverse relationships through flash cards. An addition/subtraction Number Triangle has two addends and a sum; a multiplication/division Number Triangle has two factors and a product.

Brown, Quincy; Fetter, Annie

2006-08-01

395

New Photonic Materials from Genetically Engineered Bacteriorhodopsin.  

National Technical Information Service (NTIS)

Basic research has been conducted on genetic engineering and synthesis of light-activated protein bacteriorhodopsin, and on a number of analogs for use in device application based on development of new photonic materials derived from bacteriorhodopsin.

R. Needleman

1999-01-01

396

Cooperative Effects in a One Photon Micromaser.  

National Technical Information Service (NTIS)

For small photon numbers, trapping states are difficult to detect due to the influence of the collective effects. We find that if the atoms are injected with atomic polarization, the micromaser becomes more insensitive to these effects. In particular, the...

M. Orszag

1996-01-01

397

Statistics at Square One  

NSDL National Science Digital Library

Statistics at Square One "was one of the best selling statistical text books in the UK," and it has been revised for this online edition. It was written from a medical statistics perspective, and hence many of the examples involve health related topics. Despite this recurring focus, no prior medical knowledge is required and the book can be used by anyone to learn the fundamentals of statistics. Basic concepts such as confidence intervals, correlation, and standard deviation are clearly defined and illustrated in the text. Each chapter concludes with a number of sample exercises; solutions to these problems are provided, but unfortunately there is little explanation accompanying the solutions. In most cases, however, the chapter's contents provide all the information necessary to complete the problems.

Swinscow, T. D. V. (Thomas Douglas Victor)

398

National Statistics Online  

NSDL National Science Digital Library

Perhaps you have a burning desire to find detailed statistical information about agriculture in Wales, or even about poverty in London's East End. All of this information can be found on the very thorough and usable National Statistics homepage, which provides information on Britain's economy, population, and society. Given the amount of information on the site, visitors would do well to look through the UK at a Glance area. Here they will find basic information on the gross domestic product, consumer spending, unemployment, and population estimates. Along with these aggregate figures for the entire nation, visitors can visit the neighborhood statistics section, where they can retrieve summary statistics for different locales around England and Wales. A number of fine reports based on the 2001 Census are also available for the general public's consideration, and they include considerations of the state of children's dental health to the provisioning of programs for the elderly.

399

Statistics: Cast Your Vote!  

NSDL National Science Digital Library

Before entering the main portion of this interactive introduction to statistics, visitors will have to answer a few quick questions on polls. It's actually a bit fun, and it serves as a nice introduction to the site. Once visitors are in the main site, they will get the opportunity to learn about statistics through the lens of a mock election. The site contains areas such as "How Random is Random?", "Being Confident", and "What Can Go Wrong". Along with concise explanations of each element of statistics, visitors can also take part in an interactive quiz and some additional polling activities. The site also includes a number of external links for visitors who wish to explore additional topics within the field of statistics.

400

Photon Sieve Space Telescope  

NASA Astrophysics Data System (ADS)

We are investigating new technologies for creating ultra-large apertures (>20m) for space-based imagery. Our approach has been to create diffractive primaries in flat membranes deployed from compact payloads. These structures are attractive in that they are much simpler to fabricate, launch and deploy compared to conventional three-dimensional optics. In this case the flat focusing element is a photon sieve which consists of a large number of holes in an otherwise opaque substrate. A photon sieve is essentially a large number of holes located according to an underlying Fresnel Zone Plate (FZP) geometry. The advantages over the FZP are that there are no support struts which lead to diffraction spikes in the far-field and non-uniform tension which can cause wrinkling of the substrate. Furthermore, with modifications in hole size and distribution we can achieve improved resolution and contrast over conventional optics. The trade-offs in using diffractive optics are the large amounts of dispersion and decreased efficiency. We present both theoretical and experimental results from small-scale prototypes. Several key solutions to issues of limited bandwidth and efficiency have been addressed. Along with these we have studied the materials aspects in order to optimize performance and achieve a scalable solution to an on-orbit demonstrator. Our current efforts are being directed towards an on-orbit 1m solar observatory demonstration deployed from a CubeSat bus.

Andersen, G.; Dearborn, M.; Hcharg, G.

2010-09-01

401

International Justice Statistics  

NSDL National Science Digital Library

Provides statistical information from the UN Office for Drug Control and Crime Prevention as well as other participating research institutions. Provides links to UN data collections on crime and justice as well as links to justice department websites in a number of foreign countries.

402

Statistics Revelations  

ERIC Educational Resources Information Center

The use, and misuse, of statistics is commonplace, yet in the printed format data representations can be either over simplified, supposedly for impact, or so complex as to lead to boredom, supposedly for completeness and accuracy. In this article the link to the video clip shows how dynamic visual representations can enliven and enhance the…

Chicot, Katie; Holmes, Hilary

2012-01-01

403

Matching Numbers  

NSDL National Science Digital Library

This interactive Flash version of the familiar game Concentration helps students develop number sense by matching various symbolic and pictorial representations of single digit numbers. The scoring rewards a systematic strategy over random guessing. The resource includes teacher notes with suggestions for implementation and differentiation, discussion questions, and printable sets of cards (pdf).

2014-01-01

404

photonics.com  

NSDL National Science Digital Library

It's everything photonics! From the the publishers of Photonics Spectra magazine this website will help you gain technical and practical information for every aspect of the global industry, integrating all segments of photonics: optics, lasers, imaging, fiber optics, electro-optics as well as photonic component manufacturing.

Publishing, Laurin

405

Photonics: An Enabling Technology  

NSDL National Science Digital Library

This two-page PDF, presented by the National Center for Optics and Photonics Education (OP-TEC), provides an overview of photonics, including what it is, why it's important, workforce demand for photonics technicians, the various photonics-related fields, and about the OP-TEC program.

2008-09-09

406

Protecting sing-photon multi-mode W state from photon loss  

NASA Astrophysics Data System (ADS)

Single-photon entanglement is of major importance in current quantum communications. However, it is sensitive to photon loss. In this paper, we discuss the protection of single-photon multi-mode W state with noiseless linear amplification. It is shown that the amplification factor is only decided with the transmission coefficient of the variable fiber beam splitters, and it does not change with the number of the spatial mode. This protocol may be useful in current quantum information processing.

Sheng, Yu-Bo; Ou-Yang, Yang; Zhou, Lan; Wang, Lei

2014-07-01

407

Superconducting series nanowire detector counting up to twelve photons.  

PubMed

We demonstrate a superconducting photon-number-resolving detector capable of resolving up to twelve photons at telecommunication wavelengths. It is based on a series array of twelve superconducting NbN nanowire elements, each connected in parallel with an integrated resistor. The photon-induced voltage signals from the twelve elements are summed up into a single readout pulse with a height proportional to the detected photon number. Thirteen distinct output levels corresponding to the detection of n = 0-12 photons are observed experimentally. A detailed analysis of the linearity and of the excess noise shows the potential of scaling to an even larger dynamic range. PMID:24663638

Zhou, Zili; Jahanmirinejad, Saeedeh; Mattioli, Francesco; Sahin, Döndü; Frucci, Giulia; Gaggero, Alessandro; Leoni, Roberto; Fiore, Andrea

2014-02-10

408

Graded photonic quasicrystals.  

PubMed

We introduce graded photonic quasicrystals and investigate properties of such structures on the example of a Luneburg lens based on a dodecagonal photonic quasicrystal. It is shown that the graded photonic quasicrystal lens has better focusing properties as compared with the graded photonic crystal lens in a frequency range suitable for experimental realization. The proposed graded photonic quasicrystals can be used in optical systems where compact and powerful focusing elements are required. PMID:22739847

Dyachenko, Pavel N; Pavelyev, Vladimir S; Soifer, Victor A

2012-06-15

409

Emission statistics of X-ray induced photoelectrons and its comparison with electron- and ion-induced electron emissions  

Microsoft Academic Search

The emission statistics of secondary electrons from a gold metal surface induced by monochromatic X-rays is studied by Monte Carlo simulations. The number distributions of emitted electrons n and their mean values ? are calculated systematically for incident photon energies from 1 to 100keV. The results are compared with recent experimental results measured at the SPring-8 X-ray beam facility (BL15XU).

K. Ohya; K. Inai; A. Nisawa; A. Itoh

2008-01-01

410

Preparing Multi-photon Entangled State with Beam Splitter  

NASA Astrophysics Data System (ADS)

We propose a scheme for preparing multi-photon entangled state which is useful for sub-shot-noise sensitivity with beam splitter, where the entangled degree is measured by the reciprocal of the mean quantum Fisher information per particle (RMQFIP). The multi-photon entangled state can be prepared by adjusting the transmissivity of the beam splitter and the better multi-photon entangled state can be prepared by increasing the total number of photons.

Chen, Rong-Hua; Yi, Hong-Gang

2014-05-01

411

Quantum phase transition of light in a one-dimensional photon-hopping-controllable resonator array  

NASA Astrophysics Data System (ADS)

We give a concrete experimental scheme for engineering the insulator-superfluid transition of light in a one-dimensional (1D) array of coupled superconducting stripline resonators. In our proposed architecture, the on-site interaction and the photon-hopping rate can be tuned independently by adjusting the transition frequencies of the charge qubits inside the resonators and at the resonator junctions, respectively, which permits us to systematically study the quantum phase transition of light in a complete parameter space. By combining the techniques of photon-number-dependent qubit transition and fast readout of the qubit state using a separate low-Q resonator mode, the statistical property of the excitations in each resonator can be obtained with a high efficiency. An analysis of the various decoherence sources and disorders shows that our scheme can serve as a guide to upcoming experiments involving a small number of coupled resonators.

Wu, Chun-Wang; Gao, Ming; Deng, Zhi-Jiao; Dai, Hong-Yi; Chen, Ping-Xing; Li, Cheng-Zu

2011-10-01

412

Complex Numbers  

NSDL National Science Digital Library

Written by Tony R. Kuphaldt and Jason Starck, this chapter of All About Circuit's second volume on Alternating Current describes complex numbers: "In order to successfully analyze AC circuits, we need to work with mathematical objects and techniques capable of representing these multi-dimensional quantities. Here is where we need to abandon scalar numbers for something better suited: complex numbers." In addition to the introduction and credits to contributors, the chapter has seven sections: Vectors and AC waveforms, Simple vector addition, Complex vector addition, Polar and rectangular notation, Complex number arithmetic, More on AC "polarity," and Some examples with AC circuits. Each section has clear illustrations and a concise, bulleted review of what was covered at the end.

Kuphaldt, Tony R.

2008-07-15

413

Ordering numbers  

NSDL National Science Digital Library

Khan Academy Exercise bank - Ordering numbers Students are able to use the knowledge map and progress tracking tool to record and support their learning goals. Hints are provided and supporting video tutorials are identified and linked.

Khan, Sal

2011-04-01

414

Number Line  

NSDL National Science Digital Library

In this brief article the numerous uses of the number line are detailed: counting, measurement, addition, subtraction, decimals, and fractions. The article contains visual representations of the some of the concepts and links to related topics.

2012-08-27

415

Learning Statistics By Doing Statistics  

NSDL National Science Digital Library

This article, created by Gary Smith of Pomona College, discusses a project-based approach to teaching statistics. The article focuses on the team aspect of learning, it introduces concepts such as: working with data, learning by doing, learning by writing, learning by speaking, and authentic assessment of material. An appendix contains a list of twenty projects that have been successfully assigned.

Smith, Gary

2009-02-02

416

Statistical Shorts  

NSDL National Science Digital Library

In this statistics and probability activity students must determine whether each statement is always true, sometimes true, sometimes false, or always false. Students must have a basic understanding of probability statements and the foundation for understanding mean, median, and mode in order to complete this activity for all twelve statements. In addition to the task, tips for getting started, possible solutions, a teacher resource page, and a printable page are provided.

Nrich

2013-01-01

417

Statistics I  

NSDL National Science Digital Library

Students will encounter the concept of a distribution, along with parameters that describe a distribution's "typical" values (average) and a distribution's spread (variance). To understand simple distributions and uncertainty propagation in the coming sections, it is necessary to be familiar with the concept of statistical independence. When two variables fluctuate independently, their covariance vanishes, and the variance of their sum is the sum of their variances.

Liao, David

418

Software-based photon counting telemetry receiver for an infrared communications satellite  

NASA Astrophysics Data System (ADS)

Single photon per bit optical communication between ground stations and low earth orbit satellites will enable the secure global distribution of cryptographic keys. The communications satellite AO-40 contains an experimental infra-red payload consisting of a low power 835 nm laser diode transmitter coupled to a small fixed orientation telescope transmitting 400 baud Manchester encoded data [1]. The received signal levels are of the order of 10 photons/bit for an effective telescope aperture of diameter 100 mm [2]. They therefore offer a means of validating models of low photon number OOK signal propagation and detection in the presence of atmospheric turbulence, an issue relevant to free-space quantum communications. This paper describes the design, testing and implementation of a photon counting receiver for AO-40 signals using a Labview software platform to display received data, error statistics, detection and correction (using cyclic redundancy check code CRCC 32), and clock synchronization [3]. Signals are acquired with a 300 mm f/6.3 Schmidt-Cassegrain tracking telescope coupled by 100 micron multimode fibre to a silicon APD photon counting module. References 1. R. Purvinskis, Use of the fixed orientation optical transmitter on AO-40, Internal Report, Centre for Advanced Telecommunications and Quantum Electronics, University of Canberra, 2001. 2. A. Arora, Oscar 40: A Complete Link Analysis, University of Canberra BE (Hons) Report, November 2001. 3. A. Arora, Optical Modulator and Demodulator for the Oscar-40 Satellite, University of Canberra BE Project Report , November 2001.

Arora, Ashish; Edwards, Paul J.

2004-01-01

419

Measuring photon-photon interactions via photon detection  

Microsoft Academic Search

Strong nonlinearity plays a significant role in physics, particularly in the design of novel quantum sources of light and matter as well as in quantum chemistry and quantum biology. In simple systems, the photon-photon interaction can be determined analytically. However, it becomes challenging to obtain it for more complex systems. Therefore, we show here how to measure strong nonlinearities by

Mihai A. Macovei; Mihai A

2010-01-01

420

Statistical analysis and digital processing of the Mössbauer spectra  

NASA Astrophysics Data System (ADS)

This work is focused on using the statistical methods and development of the filtration procedures for signal processing in Mössbauer spectroscopy. Statistical tools for noise filtering in the measured spectra are used in many scientific areas. The use of a pure statistical approach in accumulated Mössbauer spectra filtration is described. In Mössbauer spectroscopy, the noise can be considered as a Poisson statistical process with a Gaussian distribution for high numbers of observations. This noise is a superposition of the non-resonant photons counting with electronic noise (from ?-ray detection and discrimination units), and the velocity system quality that can be characterized by the velocity nonlinearities. The possibility of a noise-reducing process using a new design of statistical filter procedure is described. This mathematical procedure improves the signal-to-noise ratio and thus makes it easier to determine the hyperfine parameters of the given Mössbauer spectra. The filter procedure is based on a periodogram method that makes it possible to assign the statistically important components in the spectral domain. The significance level for these components is then feedback-controlled using the correlation coefficient test results. The estimation of the theoretical correlation coefficient level which corresponds to the spectrum resolution is performed. Correlation coefficient test is based on comparison of the theoretical and the experimental correlation coefficients given by the Spearman method. The correctness of this solution was analyzed by a series of statistical tests and confirmed by many spectra measured with increasing statistical quality for a given sample (absorber). The effect of this filter procedure depends on the signal-to-noise ratio and the applicability of this method has binding conditions.

Prochazka, Roman; Tucek, Pavel; Tucek, Jiri; Marek, Jaroslav; Mashlan, Miroslav; Pechousek, Jiri

2010-02-01

421

UK photonics in defence and security  

NASA Astrophysics Data System (ADS)

The UK is globally recognised as strong in Photonics. However its Photonics sector is fragmented and the size and sectors of interest have not previously been established. The UK government has instigated the formation of the Photonics Knowledge Transfer Network (PKTN) to bring the Photonics community together. The UK features in Defence & Security; Communications; Measurement; Medical Technology; Lighting; Solar Energy; Information Technology and Flat Panels. This expertise is scattered through out the UK in geographic areas each with a breadth of Photonic interests. The PKTN has mapped the UK capability in all Photonics sectors. This paper will present the capability of the Companies, Research Institutions and Infrastructure making up the Defence & Security Photonics scene in the UK. Large Defence companies in the UK are well known throughout the world. However, there are a large number of SMEs, which may not be as well known in the supply chain. These are being actively encouraged by the UK MoD to engage with the Defence & Security Market and shall be discussed here. The presentation will reference a number of organisations which help to fund and network the community, such as the Defence Technology Centres. In addition the Roadmap for Defence & Security in the UK, produced for the UK Photonics Strategy (July 2006) by the Scottish Optoelectronics Association will be described and the plans in taking it forward under the PKTN will be revealed.

Gracie, C.; Tooley, I.; Wilson, A.

2008-09-01

422

Microwave control of the interaction between two optical photons  

NASA Astrophysics Data System (ADS)

A microwave field is used to control the interaction between pairs of optical photons stored in highly excited collective states (Rydberg polaritons). We show that strong dipole-dipole interactions induced by the microwave field destroy the coherence of polariton modes with more than one Rydberg excitation. Consequently, single-polariton modes, which correspond to single stored photons, are preferentially retrieved from the sample. Measurements of the photon statistics of the retrieved light field also reveal nontrivial propagation dynamics of the interacting polaritons.

Maxwell, D.; Szwer, D. J.; Paredes-Barato, D.; Busche, H.; Pritchard, J. D.; Gauguet, A.; Jones, M. P. A.; Adams, C. S.

2014-04-01

423

Results on Photon-Photon Physics with the DM2 Detector.  

National Technical Information Service (NTIS)

The aim of this paper is to give the main results on photon-photon physics obtained with the DM2 detector at DCI (Orsay). After normalizing our experiment with the leptonic processes, we emphasize the number of produced pion pairs in the gamma gamma colli...

Z. Ajaltouni A. Falvard J. Jousset

1985-01-01

424

Web Pages That Perform Statistical Calculations: Interactive Statistical Calculation Pages  

NSDL National Science Digital Library

John Pezullo, Associate Professor of Pharmacology and Biostatistics at Georgetown University, has helped compile this monstrous metasite of freely accessible multi-platform statistical software. With links to pages around the world, the table of contents includes access to calculators, plotters, random number generators, and programs that perform literally hundreds of calculations. Hosted by America Online, the site also includes links to online statistics books, tutorials, and downloadable software. This is a virtual treasure trove of statistical calculation pages for mathematicians and statisticians.

425

Modern Statistical Methods for GLAST Event Analysis  

SciTech Connect

We describe a statistical reconstruction methodology for the GLAST LAT. The methodology incorporates in detail the statistics of the interactions of photons and charged particles with the tungsten layers in the LAT, and uses the scattering distributions to compute the full probability distribution over the energy and direction of the incident photons. It uses model selection methods to estimate the probabilities of the possible geometrical configurations of the particles produced in the detector, and numerical marginalization over the energy loss and scattering angles at each layer. Preliminary results show that it can improve on the tracker-only energy estimates for muons and electrons incident on the LAT.

Morris, Robin D.; /RIACS, Mtn. View; Cohen-Tanugi, Johann; /SLAC /KIPAC, Menlo Park

2007-04-10

426

Quantum teleportation using bipartite entangled photon-added non-linear coherent states  

NASA Astrophysics Data System (ADS)

Quantum teleportation has attracted much attention from both theorists and experimenters in the last decade. The emergence of new protocols and their actual implementation have even motivated the development of new quantum optical schemes. A key issue when teleporting a quantum state is establishing the quantum channel between sender and receiver stations, usually done by manipulating an auxiliary bipartite entangled state. The purpose of the present work is to study quantum teleportation processes in which that state is an entangled bipartite photon-added state, and the Adhikari et. al. continuous-variable quantum teleportation protocol is applied. Photon-added states can be generated using different experimental techniques, such as parametric down-conversion in a nonlinear crystal, and conditioned parametric amplification. These states are relevant because they exhibit generalized non-classical features for all orders of creation and annihilation operators, and may even show phase squeezing and sub-Poissonian distribution statistics. We study, the dependence of the fidelity of the teleported states and their photon number statistic as a function of the higher-order squeezing, and the higher-order sub-Poissonian statistic.

Castro, E.; Páez, E. J.; Ladera, C. L.; Zambrano, A.

2013-11-01

427

Design and Experiments of Photon Counting Imaging Test Platform  

Microsoft Academic Search

The photon counting avalanche photodiode (APD) imaging test platform is put up according to the semi-classical theory of photoelectric detection which the classical statistical fluctuation of the light field is combined with the fluctuation of the interaction between light and matter. A mathematical model between APD photon counting frequency's expectation and input gray levels is set up. With changes of

Liju Yin; Qian Chen

2009-01-01

428

Opportunities for single-photon detection using visible light photon counters  

NASA Astrophysics Data System (ADS)

Visible light photon counters (VLPCs) are solid-state devices providing high quantum efficiency (QE) photon detection (>88%) with photon number resolving capability and low timing jitter (~250 ps). VLPC features high QE in the 0.4-1.0?m wavelength range, as the main photon absorption mechanism is provided by electron-hole pair generation across the silicon bandgap. In this paper, we will discuss the optical and electrical operating principles of VLPCs, and propose a range of device optimization paths that improves various aspects of VLPC for advanced quantum optics and quantum information processing experiments, both in the UV and the telecom wavelength range.

Kim, Jungsang; McKay, Kyle S.; Stapelbroek, Maryn G.; Hogue, Henry H.

2011-05-01

429

Quantum statistics of optical parametric processes with squeezed reservoirs  

NASA Astrophysics Data System (ADS)

Quantum statistics including joint photon-number and integrated-intensity probability distributions are derived in time evolution of general optical parametric process involving processes of frequency conversion, parametric amplification and subharmonic generation taking into account losses and noise described by squeezed reservoirs. Using these tools quantum entanglement of modes is considered and the other nonclassical properties of the process under discussion are demonstrated by means of conditional probability distributions and their Fano factors, difference-number probability distributions, quantum oscillations, squeezing of vacuum fluctuations and negative values of the joint and difference wave probability quasidistributions. Nonclassical properties are illustrated for spontaneous process as well as stimulated process by means of chaotic light and squeezed vacuum field. Multimode processes are investigated in the spirit of the Mandel-Rice photocount formula.

Pe?ina, Jan; K?epelka, Jaromír

2013-11-01

430

A multi-functional superconductor single-photon detector at telecommunication wavelength  

NASA Astrophysics Data System (ADS)

A multi-functional single-photon detector was demonstrated to resolve photon states by multiple superconductor single photon detectors (SSPDs) system with improved readout settings. The photon number and space distribution were resolved simultaneously by the presented system, which inherits the merits of SSPD, such as wide-response band, high repetition rate and working stability. Experimentally, four photons were resolved and the photon distribution over three pixels was figured out according to the amplitudes of output pulses at the telecommunication wavelength. The extension of this proposal to incorporate more elements for resolving more photons and revealing photons spatial distribution over larger scale is also discussed.

Zhang, Labao; Gu, Min; Jia, Tao; Qiu, Jian; Kang, Lin; Sun, Guozhu; Chen, Jian; Jin, Biaobin; Xu, Weiwei; Wu, Peiheng

2014-06-01

431

Number Cruncher  

NSDL National Science Digital Library

Similar to the original "Function Machine" but lists input and output in a table and will not let the user attempt to guess the rule without having at least two data points. Number Cruncher is one of the Interactivate assessment explorers.

432

Number Patterns  

NSDL National Science Digital Library

In this lesson, learners are challenged to discover the relationship among six numbers. The objective of this activity is to engage learners in a problem-solving situation in which they practice aspects of the process of science. Learners can use an included Science Flowchart to chart their scientific experience. This lesson serves as a good introduction to the nature of scientific inquiry.

Scotchmoor, Judy

2010-01-01

433

Numbers Sense  

ERIC Educational Resources Information Center

This article reports on work undertaken by schools as part of Qualifications and Curriculum Authority's (QCA's) "Engaging mathematics for all learners" project. The goal was to use in the classroom, materials and approaches from a Royal Institution (Ri) Year 10 master-class, "Number Sense", which was inspired by examples from Michael Blastland and…

Kathotia, Vinay

2009-01-01

434

SOCR: Statistics Online Computational Resource  

ERIC Educational Resources Information Center

The need for hands-on computer laboratory experience in undergraduate and graduate statistics education has been firmly established in the past decade. As a result a number of attempts have been undertaken to develop novel approaches for problem-driven statistical thinking, data analysis and result interpretation. In this paper we describe an…

Dinov, Ivo D.

2006-01-01

435

Book Trade Research and Statistics.  

ERIC Educational Resources Information Center

The six articles in this section examine prices of U.S. and foreign materials; book title output and average prices; book sales statistics; U.S. book exports and imports; number of book outlets in the United States and Canada; and book review media statistics. (LRW)

Alexander, Adrian W.; And Others

1994-01-01

436

Book Trade Research and Statistics.  

ERIC Educational Resources Information Center

Presents: "Prices of United States and Foreign Published Materials"; "Book Title Output and Average Prices"; "Book Sales Statistics, 1998"; "United States Book Exports and Imports: 1998"; "International Book Title Output: 1990-96"; "Number of Book Outlets in the United States and Canada"; and "Book Review Media Statistics". (AEF)

Bosch, Stephen; Ink, Gary; Greco, Albert N.

1999-01-01

437

Atom–light interactions in photonic crystals  

NASA Astrophysics Data System (ADS)

The integration of nanophotonics and atomic physics has been a long-sought goal that would open new frontiers for optical physics, including novel quantum transport and many-body phenomena with photon-mediated atomic interactions. Reaching this goal requires surmounting diverse challenges in nanofabrication and atomic manipulation. Here we report the development of a novel integrated optical circuit with a photonic crystal capable of both localizing and interfacing atoms with guided photons. Optical bands of a photonic crystal waveguide are aligned with selected atomic transitions. From reflection spectra measured with average atom number , we infer that atoms are localized within the waveguide by optical dipole forces. The fraction of single-atom radiative decay into the waveguide is ?1D/???(0.32±0.08), where ?1D is the rate of emission into the guided mode and ?? is the decay rate into all other channels. ?1D/?? is unprecedented in all current atom–photon interfaces.

Goban, A.; Hung, C.-L.; Yu, S.-P.; Hood, J. D.; Muniz, J. A.; Lee, J. H.; Martin, M. J.; McClung, A. C.; Choi, K. S.; Chang, D. E.; Painter, O.; Kimble, H. J.

2014-05-01

438

Teleporting photonic qudits using multimode quantum scissors.  

PubMed

Teleportation plays an important role in the communication of quantum information between the nodes of a quantum network and is viewed as an essential ingredient for long-distance Quantum Cryptography. We describe a method to teleport the quantum information carried by a photon in a superposition of a number d of light modes (a "qudit") by the help of d additional photons based on transcription. A qudit encoded into a single excitation of d light modes (in our case Laguerre-Gauss modes which carry orbital angular momentum) is transcribed to d single-rail photonic qubits, which are spatially separated. Each single-rail qubit consists of a superposition of vacuum and a single photon in each one of the modes. After successful teleportation of each of the d single-rail qubits by means of "quantum scissors" they are converted back into a qudit carried by a single photon which completes the teleportation scheme. PMID:24352610

Goyal, Sandeep K; Konrad, Thomas

2013-01-01

439

Teleporting photonic qudits using multimode quantum scissors  

NASA Astrophysics Data System (ADS)

Teleportation plays an important role in the communication of quantum information between the nodes of a quantum network and is viewed as an essential ingredient for long-distance Quantum Cryptography. We describe a method to teleport the quantum information carried by a photon in a superposition of a number d of light modes (a ``qudit'') by the help of d additional photons based on transcription. A qudit encoded into a single excitation of d light modes (in our case Laguerre-Gauss modes which carry orbital angular momentum) is transcribed to d single-rail photonic qubits, which are spatially separated. Each single-rail qubit consists of a superposition of vacuum and a single photon in each one of the modes. After successful teleportation of each of the d single-rail qubits by means of ``quantum scissors'' they are converted back into a qudit carried by a single photon which completes the teleportation scheme.

Goyal, Sandeep K.; Konrad, Thomas

2013-12-01

440

Statistical Decisions Utilizing Neural Nets.  

National Technical Information Service (NTIS)

Neural networks were developed that accurately determine the statistical characteristics: modality and number fo stochastic components of underlying probability distribution(s) for sample data. Sample data examples, used to teach the neural nets were gene...

G. Schlenker J. Manata

1990-01-01

441

From Two-Photon Correlated Emission Laser to Entanglement Amplifier  

NASA Astrophysics Data System (ADS)

The correlation of two spontaneous emission events is the fundation of correlated emission lasers (CEL). We consider a two-photon correlated emission laser as a source of an entangled radiation with a large number of photons in each mode. We study the dynamics of this system in the presence of cavity losses, concluding that the creation of entangled states with photon numbers up to tens of thousands seems achievable.

Xiong, Han; Scully, Marlan O.; Zubairy, M. Suhail

2004-10-01

442

Photonic Crystal Fiber Based Entangled Photon Sources.  

National Technical Information Service (NTIS)

We generate high-purity correlated and entangled photon- pairs at the telecom wavelengths in a cooled 10-meter highly nonlinear fiber (HNLF). In our previous project (contract no: FA8750-12-1-0136), we were able to generate correlated/entangled photon-pai...

K. F. Lee

2014-01-01

443

The Statistical Fermi Paradox  

NASA Astrophysics Data System (ADS)

In this paper is provided the statistical generalization of the Fermi paradox. The statistics of habitable planets may be based on a set of ten (and possibly more) astrobiological requirements first pointed out by Stephen H. Dole in his book Habitable planets for man (1964). The statistical generalization of the original and by now too simplistic Dole equation is provided by replacing a product of ten positive numbers by the product of ten positive random variables. This is denoted the SEH, an acronym standing for “Statistical Equation for Habitables”. The proof in this paper is based on the Central Limit Theorem (CLT) of Statistics, stating that the sum of any number of independent random variables, each of which may be ARBITRARILY distributed, approaches a Gaussian (i.e. normal) random variable (Lyapunov form of the CLT). It is then shown that: 1. The new random variable NHab, yielding the number of habitables (i.e. habitable planets) in the Galaxy, follows the log- normal distribution. By construction, the mean value of this log-normal distribution is the total number of habitable planets as given by the statistical Dole equation. 2. The ten (or more) astrobiological factors are now positive random variables. The probability distribution of each random variable may be arbitrary. The CLT in the so-called Lyapunov or Lindeberg forms (that both do not assume the factors to be identically distributed) allows for that. In other words, the CLT "translates" into the SEH by allowing an arbitrary probability distribution for each factor. This is both astrobiologically realistic and useful for any further investigations. 3. By applying the SEH it is shown that the (average) distance between any two nearby habitable planets in the Galaxy may be shown to be inversely proportional to the cubic root of NHab. This distance is denoted by new random variable D. The relevant probability density function is derived, which was named the "Maccone distribution" by Paul Davies in 2008. 4. A practical example is then given of how the SEH works numerically. Each of the ten random variables is uniformly distributed around its own mean value as given by Dole (1964) and a standard deviation of 10% is assumed. The conclusion is that the average number of habitable planets in the Galaxy should be around 100 million ±200 million, and the average distance in between any two nearby habitable planets should be about 88 light years ±40 light years. 5. The SEH results are matched against the results of the Statistical Drake Equation from reference 4. As expected, the number of currently communicating ET civilizations in the Galaxy turns out to be much smaller than the number of habitable planets (about 10,000 against 100 million, i.e. one ET civilization out of 10,000 habitable planets). The average distance between any two nearby habitable planets is much smaller that the average distance between any two neighbouring ET civilizations: 88 light years vs. 2000 light years, respectively. This means an ET average distance about 20 times higher than the average distance between any pair of adjacent habitable planets. 6. Finally, a statistical model of the Fermi Paradox is derived by applying the above results to the coral expansion model of Galactic colonization. The symbolic manipulator "Macsyma" is used to solve these difficult equations. A new random variable Tcol, representing the time needed to colonize a new planet is introduced, which follows the lognormal distribution, Then the new quotient random variable Tcol/D is studied and its probability density function is derived by Macsyma. Finally a linear transformation of random variables yields the overall time TGalaxy needed to colonize the whole Galaxy. We believe that our mathematical work in deriving this STATISTICAL Fermi Paradox is highly innovative and fruitful for the future.

Maccone, C.

444

Table Numbers  

NSDL National Science Digital Library

This interactive applet helps students develop fluency with multiplication facts. Users chose a factor from among the digits 1-9, each of which is associated with a mnemonic graphic. The applet then displays three numbers and the user selects the one which is a multiple of the chosen factor. The player must respond correctly to ten examples to complete a round. A one-point penalty for selecting an incorrect product discourages guessing. The few words that are displayed are in Dutch.

2008-01-01

445

Statistical Constraints on Joy's Law  

NASA Astrophysics Data System (ADS)

Using sunspot data from the observatories at Mt. Wilson and Kodaikanal, active region tilt angles are analyzed for different active region sizes and latitude bins. A number of similarly-shaped statistical distributions were fitted to the data using maximum likelihood estimation. In all cases, we find that the statistical distribution best describing the number of active regions at a given tilt angle is a Laplace distribution with the form (2?)-1*exp(-|x-?|/?), with 2° ? ? ? 11°, and 10° ? ? ? 40°.

Amouzou, Ernest C.; Munoz-Jaramillo, Andres; Martens, Petrus C.; DeLuca, Edward E.

2014-06-01

446

A study of photon interaction parameters in lung tissue substitutes  

PubMed Central

The study of photon interaction with different composite materials has become a topic of prime importance for radiation physicists. Some parameters of dosimetric interest are the mass attenuation coefficient, effective atomic number, and electron density; these help in the basic understanding of photon interactions with composite materials. The photon interaction parameters such as mass attenuation coefficient (?/?), effective atomic number (Zeff), and effective electron density (Nel) must be identical for the phantom material and their tissue. In the present study, we have evaluated the photon interaction parameters such as (?/?), Zeff and Nel of 13 lung tissue substitutes. The variations of these parameters of lung tissue substitutes with photon energy are graphically represented. The photon interaction parameters of lung tissue substitutes are compared with that of lung tissue. The variation of photon interaction parameters of the studied lung tissue substitutes is similar that of the lung. Logically, it can be shown that Alderson lung is good substitute for lung than the other substitutes.

Manjunatha, H. C.

2014-01-01

447

Photonic crystal light source  

SciTech Connect

A light source is provided by a photonic crystal having an enhanced photonic density-of-states over a band of frequencies and wherein at least one of the dielectric materials of the photonic crystal has a complex dielectric constant, thereby producing enhanced light emission at the band of frequencies when the photonic crystal is heated. The dielectric material can be a metal, such as tungsten. The spectral properties of the light source can be easily tuned by modification of the photonic crystal structure and materials. The photonic crystal light source can be heated electrically or other heating means. The light source can further include additional photonic crystals that exhibit enhanced light emission at a different band of frequencies to provide for color mixing. The photonic crystal light source may have applications in optical telecommunications, information displays, energy conversion, sensors, and other optical applications.

Fleming, James G. (Albuquerque, NM); Lin, Shawn-Yu (Albuquerque, NM); Bur, James A. (Corrales, NM)

2004-07-27

448

Photonic crystal fibers  

Microsoft Academic Search

Photonic crystal fibers having a complex microstructure in the transverse plane constitute a new and promising class of optical fibers. Such fibers can either guide light through total internal reflection or the photonic bandgap effect, In this paper, we review the different types and applications of photonic crystal fibers with particular emphasis on recent advances in the field.

J. Laegsgaard; K. P. Hansen; M. D. Nielsen; T. P. Hansen; J. Riishede; K. Hougaard; T. Sorensen; T. T. Larsen; N. A. Mortensent; J. Broeng; J. B. Jensen; A. Bjarklev

2003-01-01

449

Hierarchical Photon Mapping  

Microsoft Academic Search

Photon mapping is an efficient method for producing high-quality, photorealistic images with full global illumination. In this paper we present a more accurate and efficient approach to final gathering using the photon map based upon hierarchical evaluation of the photons over each surface. We use the footprint of each gather ray to calculate the irradiance estimate area rather than deriving

Ben Spencer; Mark W. Jones

2009-01-01

450

Statistics: Batter Up!  

NSDL National Science Digital Library

In this unit from the Baseball Hall of Fame, students apply number and operation skills while learning how several basic baseball statistics are calculated and used to make decisions. The Rookie level, for elementary grades, consists of 5 pdf files: an overview and 4 lessons involving whole numbers, fractions, and decimals. Lessons are aligned to CCSSM and include instructions, student activity sheets, and answer keys. The unit can be used to enhance a Hall of Fame field trip or videoconference experience, or to enrich the regular math curriculum.

Campbell, Thomas E.; Crocker, Daniel T.

2012-01-01

451

Statistical Support for the Atl Program.  

National Technical Information Service (NTIS)

Statistical experimental designs are presented for various numbers of organisms and agar solutions pertinent to the experiment, 'colony growth in zero gravity'. Missions lasting 7 and 30 days are considered. For the designs listed, the statistical analysi...

K. Hinkelmann R. H. Myers

1976-01-01

452

Multiplexing photons with a binary division strategy  

NASA Astrophysics Data System (ADS)

We present a scheme to produce clock-synchronized photons from a single parametric downconversion source with a binary division strategy. The time difference between a clock and detections of the herald photons determines the amount of delay that must be imposed to a photon by actively switching different temporal segments, so that all photons emerge from the output with their wavepackets temporally synchronized with the temporal reference. The operation is performed using a binary division configuration which minimizes the passages through switches. Finally, we extend this scheme to the production of many synchronized photons and find expressions for the optimal amount of correction stages as a function of the pair generation rate and the target coherence time. Our results show that, for the generation of this heralded single-photon per output state at an optimized input photon flux, the output rate of our scheme scales essentially with the reciprocal of the target output photon number. With current technology, rates of up to 104 synchronized pairs per second could be observed with only 7 correction stages.

Schmiegelow, Christian Tomás; Larotonda, Miguel Antonio

2013-11-01

453

Integrated approach for estimation and restoration of photon-limited images based on steerable pyramids  

Microsoft Academic Search

In disciplines like fluorescence microscopy and astronomical imaging, the imaging process is based on detection of photons. Fluctuations in photon counting processes are described by Poisson statistics. In this paper, a new combined method based on steerable pyramids is proposed for the estimation of the degradation parameters (like noise and blur) and the restoration of photon-limited images. It consists of

Filip Rooms; Wilfried Philips; Patrick Van Oostveldt

2003-01-01

454

Ultrafast photonic crystal optical switching  

Microsoft Academic Search

Photonic crystal, a novel and artificial photonic material with periodic dielectric distribution, possesses photonic bandgap\\u000a and can control the propagation states of photons. Photonic crystal has been considered to be a promising candidate for the\\u000a future integrated photonic devices. The properties and the fabrication method of photonic crystal are expounded. The progresses\\u000a of the study of ultrafast photonic crystal optical

Qi-Huang Gong; Xiao-Yong Hu

2006-01-01

455

Information-efficient phase imaging with heralded single photons  

NASA Astrophysics Data System (ADS)

We report progress toward the experimental realization of information-efficient quantum imaging, here at two bits per photon. A heralded single-photon source (g^2(0)<0.08) is used as the input to a 4x4 multiport interferometer, compactly implemented using both polarization and spatial degrees of freedom. The interferometer can be used to read out all 4 Hadamard phase codes with a single photon. We investigate the use of cavity-enhanced spontaneous parametric downconversion for the coherent source of heralded photons. The photon-number-resolving ability of high-quantum-efficiency transition edge sensors is used for the heralding and detection.

Shahrokhshahi, Reihaneh; Sridhar, Niranjan; Pfister, Olivier; Guha, Saikat; Habif, Jonathan; Miller, Aaron; Lita, Adriana; Calkins, Brice; Gerritts, Thomas; Lamas-Linares, Antia; Nam, Sae Woo

2013-03-01

456

Spectral and temporal distribution of phase-conjugated fluorescent photons  

NASA Astrophysics Data System (ADS)

Spontaneous emission of fluorescence radiation by an atom near the surface of a four-wave mixing phase conjugator is considered. It is shown that the spectral photon distribution consists of two Lorentzians, which have their peaks symmetrically located at the two sides of the pump frequency omega (bar) of the nonlinear crystal. With omega sub 0, the atomic resonance, the line at 2 omega(bar)-omega sub 0 is more than twice as strong as the line at omega sub 0. When the phase-conjugate reflectivity exceeds unity, the temporal photon distribution exhibits nonclassical behavior. Then, antibunching of photons prevails, and the photon statistics is sub-poissonian.

Arnoldus, Henk F.; George, Thomas F.

1990-12-01

457

Ultrabright source of entangled photon pairs.  

PubMed

A source of triggered entangled photon pairs is a key component in quantum information science; it is needed to implement functions such as linear quantum computation, entanglement swapping and quantum teleportation. Generation of polarization entangled photon pairs can be obtained through parametric conversion in nonlinear optical media or by making use of the radiative decay of two electron-hole pairs trapped in a semiconductor quantum dot. Today, these sources operate at a very low rate, below 0.01 photon pairs per excitation pulse, which strongly limits their applications. For systems based on parametric conversion, this low rate is intrinsically due to the Poissonian statistics of the source. Conversely, a quantum dot can emit a single pair of entangled photons with a probability near unity but suffers from a naturally very low extraction efficiency. Here we show that this drawback can be overcome by coupling an optical cavity in the form of a 'photonic molecule' to a single quantum dot. Two coupled identical pillars-the photonic molecule-were etched in a semiconductor planar microcavity, using an optical lithography method that ensures a deterministic coupling to the biexciton and exciton energy states of a pre-selected quantum dot. The Purcell effect ensures that most entangled photon pairs are emitted into two cavity modes, while improving the indistinguishability of the two optical recombination paths. A polarization entangled photon pair rate of 0.12 per excitation pulse (with a concurrence of 0.34) is collected in the first lens. Our results open the way towards the fabrication of solid state triggered sources of entangled photon pairs, with an overall (creation and collection) efficiency of 80%. PMID:20613838

Dousse, Adrien; Suffczy?ski, Jan; Beveratos, Alexios; Krebs, Olivier; Lemaître, Aristide; Sagnes, Isabelle; Bloch, Jacqueline; Voisin, Paul; Senellart, Pascale

2010-07-01

458

Number 8  

NASA Technical Reports Server (NTRS)

29 January 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a spotted, high latitude plain, south of the Argyre basin. When the image was received from Mars by the MOC operations team, they noticed -- with a sense of humor -- the number '8' on this martian surface. The '8' is located at the center-right and is formed by the rims of two old impact craters that have been eroded and partly-filled and partly-buried beneath the surface.

Location near: 68.6oS, 38.4oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

2006-01-01

459

The Statistical Drake Equation  

NASA Astrophysics Data System (ADS)

We provide the statistical generalization of the Drake equation. From a simple product of seven positive numbers, the Drake equation is now turned into the product of seven positive random variables. We call this "the Statistical Drake Equation". The mathematical consequences of this transformation are then derived. The proof of our results is based on the Central Limit Theorem (CLT) of Statistics. In loose terms, the CLT states that the sum of any number of independent random variables, each of which may be ARBITRARILY distributed, approaches a Gaussian (i.e. normal) random variable. This is called the Lyapunov Form of the CLT, or the Lindeberg Form of the CLT, depending on the mathematical constraints assumed on the third moments of the various probability distributions. In conclusion, we show that: The new random variable N, yielding the number of communicating civilizations in the Galaxy, follows the LOGNORMAL distribution. Then, as a consequence, the mean value of this lognormal distribution is the ordinary N in the Drake equation. The standard deviation, mode, and all the moments of this lognormal N are also found. The seven factors in the ordinary Drake equation now become seven positive random variables. The probability distribution of each random variable may be ARBITRARY. The CLT in the so-called Lyapunov or Lindeberg forms (that both do not assume the factors to be identically distributed) allows for that. In other words, the CLT "translates" into our statistical Drake equation by allowing an arbitrary probability distribution for each factor. This is both physically realistic and practically very useful, of course. An application of our statistical Drake equation then follows. The (average) DISTANCE between any two neighboring and communicating civilizations in the Galaxy may be shown to be inversely proportional to the cubic root of N. Then, in our approach, this distance becomes a new random variable. We derive the relevant probability density function, apparently previously unknown and dubbed "Maccone distribution" by Paul Davies. DATA ENRICHMENT PRINCIPLE. It should be noticed that ANY positive number of random variables in the Statistical Drake Equation is compatible with the CLT. So, our generalization allows for many more factors to be added in the future as long as more refined scientific knowledge about each factor will be known to the scientists. This capability to make room for more future factors in the statistical Drake equation, we call the "Data Enrichment Principle," and we regard it as the key to more profound future results in the fields of Astrobiology and SETI. Finally, a practical example is given of how our statistical Drake equation works numerically. We work out in detail the case, where each of the seven random variables is uniformly distributed around its own mean value and has a given standard deviation. For instance, the number of stars in the Galaxy is assumed to be uniformly distributed around (say) 350 billions with a standard deviation of (say) 1 billion. Then, the resulting lognormal distribution of N is computed numerically by virtue of a MathCad file that the author has written. This shows that the mean value of the lognormal random variable N is actually of the same order as the classical N given by the ordinary Drake equation, as one might expect from a good statistical generalization.

Maccone, Claudio

2010-12-01

460

Scalable Spatial Superresolution Using Entangled Photons  

NASA Astrophysics Data System (ADS)

N00N states—maximally path-entangled states of N photons—exhibit spatial interference patterns sharper than any classical interference pattern. This is known as superresolution. However, even given perfectly efficient number-resolving detectors, the detection efficiency of all previous measurements of such interference would decrease exponentially with the number of photons in the N00N state, often leading to the conclusion that N00N states are unsuitable for spatial measurements. A technique known as the "optical centroid measurement" has been proposed to solve this and has been experimentally verified for photon pairs; here we present the first extension beyond two photons, measuring the superresolution fringes of two-, three-, and four-photon N00N states. Moreover, we compare the N00N-state interference to the corresponding classical superresolution interference. Although both provide the same increase in spatial frequency, the visibility of the classical fringes decreases exponentially with the number of detected photons. Our work represents an essential step forward for quantum-enhanced measurements, overcoming what was believed to be a fundamental challenge to quantum metrology.

Rozema, Lee A.; Bateman, James D.; Mahler, Dylan H.; Okamoto, Ryo; Feizpour, Amir; Hayat, Alex; Steinberg, Aephraim M.

2014-06-01

461

Scalable spatial superresolution using entangled photons.  

PubMed

N00N states-maximally path-entangled states of N photons-exhibit spatial interference patterns sharper than any classical interference pattern. This is known as superresolution. However, even given perfectly efficient number-resolving detectors, the detection efficiency of all previous measurements of such interference would decrease exponentially with the number of photons in the N00N state, often leading to the conclusion that N00N states are unsuitable for spatial measurements. A technique known as the "optical centroid measurement" has been proposed to solve this and has been experimentally verified for photon pairs; here we present the first extension beyond two photons, measuring the superresolution fringes of two-, three-, and four-photon N00N states. Moreover, we compare the N00N-state interference to the corresponding classical superresolution interference. Although both provide the same increase in spatial frequency, the visibility of the classical fringes decreases exponentially with the number of detected photons. Our work represents an essential step forward for quantum-enhanced measurements, overcoming what was believed to be a fundamental challenge to quantum metrology. PMID:24949765

Rozema, Lee A; Bateman, James D; Mahler, Dylan H; Okamoto, Ryo; Feizpour, Amir; Hayat, Alex; Steinberg, Aephraim M

2014-06-01

462

The Photon Underproduction Crisis  

NASA Astrophysics Data System (ADS)

We examine the statistics of the low-redshift Ly? forest from smoothed particle hydrodynamic simulations in light of recent improvements in the estimated evolution of the cosmic ultraviolet background (UVB) and recent observations from the Cosmic Origins Spectrograph (COS). We find that the value of the metagalactic photoionization rate (?HI) required by our simulations to match the observed properties of the low-redshift Ly? forest is a factor of five larger than the value predicted by state-of-the art models for the evolution of this quantity. This mismatch in ?HI results in the mean flux decrement of the Ly? forest being overpredicted by at least a factor of two (a 10? discrepancy with observations) and a column density distribution of Ly? forest absorbers systematically and significantly elevated compared to observations over nearly two decades in column density. We examine potential resolutions to this mismatch and find that either conventional sources of ionizing photons (galaxies and quasars) must contribute considerably more than cur