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1

Photon number statistics of NV centre emission  

NASA Astrophysics Data System (ADS)

Optical sources that deterministically produce single photons with a high suppression of multi-photon emission and a negligible background component are promising candidates for standard sources for quantum metrology, quantum communication and foundations of quantum mechanics. In this paper, the photon number distribution of non-classical light emitted by nitrogen vacancy (NV) centres in nano-diamonds is studied by three different experimental techniques. The photon number resolving transition edge sensor (TES) detector and the On/Off detection method are applied to determine the diagonal elements of the optical density matrix. From the data measured by the two methods the second order correlation function at time delay zero is calculated and compared with the g2(0)-values obtained by Hanbury Brown-Twiss (HBT) interferometric measurements. Among the g2(0)-values evaluated with the three techniques, we found good agreement in the results for a single photon emitter with a g2(0)-value close to zero and a multi-photon source with a g2(0)-value of approximately 0.5.

Schmunk, W.; Gramegna, M.; Brida, G.; Degiovanni, I. P.; Genovese, M.; Hofer, H.; Kück, S.; Lolli, L.; Paris, M. G. A.; Peters, S.; Rajteri, M.; Racu, A. M.; Ruschhaupt, A.; Taralli, E.; Traina, P.

2012-04-01

2

Transfer of photon number statistics from coupling light to stored and retrieved probe light.  

PubMed

We report on the transfer of statistical characteristics from writing and reading coupling light to stored and retrieved probe light pulses in a ?-type electromagnetically induced transparency (EIT) scheme based on the 5S(1/2)-5P(1/2) transition of (87)Rb atoms. When the coherent probe laser pulse was stored in the EIT medium using the pseudo-thermal coupling light, the characteristics of the pseudo-thermal writing coupling light were transferred to the stored probe laser pulse because of the strong correlation between the probe and coupling light in the EIT medium. The photon number statistics of the retrieved probe light changed from Poisson distribution to Bose-Einstein distribution. Additionally, we measured the change in the properties of the retrieved light pulse due to the photon number statistics of the pseudo-thermal reading coupling light. PMID:23187485

Bae, In-Ho; Moon, Han Seb

2012-11-19

3

Experimental joint signal-idler quasidistributions and photon-number statistics for mesoscopic twin beams  

SciTech Connect

Joint signal-idler photoelectron distributions of twin beams containing several tens of photons per mode have been measured recently. Exploiting a microscopic quantum theory for joint quasidistributions in parametric down-conversion developed earlier we characterize properties of twin beams in terms of quasidistributions using experimental data. Negative values as well as oscillating behavior in the quantum region are characteristic for the subsequently determined joint signal-idler quasidistributions of integrated intensities. Also the conditional and difference photon-number distributions are shown to be sub-Poissonian and sub-shot-noise, respectively.

Perina, Jan [Joint Laboratory of Optics, Palacky University and Institute of Physics of Academy of Sciences of the Czech Republic, 17. listopadu 50a, 772 07 Olomouc (Czech Republic); Department of Optics, Palacky University, 17. listopadu 50, 772 07 Olomouc (Czech Republic); Krepelka, Jaromir; Perina, Jan Jr. [Joint Laboratory of Optics, Palacky University and Institute of Physics of Academy of Sciences of the Czech Republic, 17. listopadu 50a, 772 07 Olomouc (Czech Republic); Bondani, Maria [National Laboratory for Ultrafast and Ultraintense Optical Science C.N.R.-I.N.F.M., Via Valleggio 11, 22100 Como (Italy); Allevi, Alessia; Andreoni, Alessandra [Department of Physics and Mathematics, University of Insubria and C.N.R.-I.N.F.M, Via Valleggio 11, 22100 Como (Italy)

2007-10-15

4

Photon Statistics of Random Lasers  

NASA Astrophysics Data System (ADS)

We have investigated the photon statistics of random lasers with coherent feedback. When the optical gain exceeds a threshold, the light field in a random medium undergoes a second-order phase transition. The photon number distribution in a single mode changes continuously from Bose-Einstein distribution at the threshold to Poisson distribution well above the threshold. The second-order correlation coefficient drops gradually from 2 to 1. Our result demonstrates that coherent light can be generated from a disordered medium with large scattering strength and high optical gain. The photon statistics of a random laser with coherent feedback is very different from that of a random laser with incoherent feedback. This difference reveals very different lasing mechanisms for the two types of random lasers.

Cao, Hui

2002-03-01

5

Photon statistics in adaptive optics  

NASA Astrophysics Data System (ADS)

Random aberrations due to atmospheric turbulence determine the angular resolution of ground-based telescopes. Adaptive optics systems compensate the wavefront degradation before detection. Although systems with a large number of subapertures in the wavefront sensor and of actuators in the deformable mirror provide the best results, they are complicated and expensive. In contrast, simpler adaptive optics systems, (less than one actuator per atmospheric coherence diameter), compensate partially the wavefront distortions, having great potential application. The statistics of the image plane light intensity in partial compensation have been described using the Rician distribution. In order to achieve a more complete description of the phenomena, we describe the photon statistics in the whole image plane using the Poisson transform of the Rician distribution. When there is no compensation, the photon statistics follow a Bose-Einstein distribution. In partial compensation the PSF is composed by a bright core, where the photon statistics follow a Laguerre distribution, surrounded by a speckled halo with Bose- Einstein statistics. Some special cases have been studied and useful approximations have been derived. Theoretical results fit well with simulated values. This description of the light statistics as a function of the compensation may be used to extract more information about the object.

Cagigal, Manuel P.; Canales, Vidal F.

1999-12-01

6

Titanium Superconducting Photon-Number-Resolving Detector  

Microsoft Academic Search

High-efficiency photon-number-resolving detectors have been developed using titanium-based transition-edge sensors. Device performances have been evaluated with respect to the response photon distribution, dark count, and timing jitter. In the analysis of the photon statistics, the observed detection probabili- ties were consistent with Poisson distributions. From a comparison of the measured distribution with theory, 98% detection efficiency was deduced at 850

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

2011-01-01

7

Photon statistics in the macroscopic realm measured without photon counters  

SciTech Connect

In a macroscopic realm, in which photons are too many to be counted by any photon-counting detector, photon statistics can be measured by using detectors simply endowed with linear response. We insert one of such detectors in a conventional photon-counting apparatus, which returns a voltage every time the detector responds to light by generating a number of elementary charges via its primary photodetection process. We only assume that, when a single charge is photogenerated, the probability density of the voltages is a distribution that is narrow with respect to its mean value. Under this hypothesis the output voltages can be suitably binned so that their probability distribution is the same as that of the photogenerated charges, that is, of the detected photons.

Andreoni, Alessandra; Bondani, Maria [Dipartimento di Fisica e Matematica, Universita degli Studi dell'Insubria and CNISM, U.d.R. Como, I-22100 Como (Italy); National Laboratory for Ultrafast and Ultraintense Optical Science, CNR-INFM and CNISM, U.d.R. Como, I-22100 Como (Italy)

2009-07-15

8

Fundamental studies of photon statistics  

NASA Astrophysics Data System (ADS)

The final technical report on research performed under the Office of Naval Research (ONR) Contract Fundamental Studies of Photon Statistics, emphasizes some of the most interesting results obtained. They deal with non-classical interference, violations of locality, and the determination of the time interval between two photons with femtosecond accuracy. Some possibilities for a new type of optical communication channel were explored. The research resulted in 62 publications and 88 lectures or papers presented at scientific meetings and seminars. These are all listed. Seven graduate students completed Ph.D. degrees with support from the ONR contract.

Mandel, Leonard

1990-01-01

9

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

10

Photon counting statistics using a digital oscilloscope  

NASA Astrophysics Data System (ADS)

We present a photon counting experiment designed for an undergraduate physics laboratory. The statistics of the number of photons of a pseudo-thermal light source is studied in two limiting cases: much longer and much shorter than the coherence time, giving Poisson and Bose-Einstein distributions, respectively. The experiment can be done in a reasonable time using a digital oscilloscope without the need of counting boards. The use of the oscilloscope has the advantage of allowing the storage of the data for further processing. The stochastic nature of the detection phenomena adds additional value because students are forced to do data processing and analysis.

Martínez Ricci, M. L.; Mazzaferri, J.; Bragas, A. V.; Martínez, O. E.

2007-08-01

11

Photon statistical properties of multiple-photon-subtracted two-mode squeezed coherent states  

NASA Astrophysics Data System (ADS)

We investigate how the combination of photon subtraction and coherent displacement affects the photon statistical properties of the multiple-photon-subtracted two-mode squeezed coherent states (PS-TMSCS). We find that the photon statistical properties are sensitive to the compound phase involved in the TMSCS. Our numerical analysis shows that the photon subtraction can enhance the cross-correlation and anti-bunching effects of the PS-TMSCS. Compared with that of the TMSCS, the photon number distribution of the PS-TMSCS is modulated by a factor that is a monotonically increasing function of the numbers of subtracting photons from each mode. And the photon subtraction essentially shifts the photon number distribution.

Wang, Shuai; Yuan, Hong-chuan; Xu, Xue-fen

2013-07-01

12

Fiber-assisted detection with photon number resolution  

Microsoft Academic Search

We report the development of a photon-number-resolving detector based on a fiber-optical setup and a pair of standard avalanche photodiodes. The detector is capable of resolving individual photon numbers and operates on the well-known principle by which a single-mode input state is split into a large number (eight) of output modes. We reconstruct the photon statistics of weak coherent input

Daryl Achilles; Christine Silberhorn; Cezary Sliwa; Konrad Banaszek; Ian A. Walmsley

2003-01-01

13

Quantum random number generator using photon-number path entanglement  

NASA Astrophysics Data System (ADS)

We report an experimental implementation of quantum random number generator based on the photon-number-path entangled state. The photon-number-path entangled state is prepared by means of two-photon Hong-Ou-Mandel quantum interference at a beam splitter. The randomness in our scheme is of truly quantum mechanical origin as it comes from the projection measurement of the entangled two-photon state. The generated bit sequences satisfy the standard randomness test.

Kwon, Osung; Cho, Young-Wook; Kim, Yoon-Ho

2010-08-01

14

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

15

Photon Statistics of Random Lasers with Resonant Feedback  

NASA Astrophysics Data System (ADS)

We have measured the photon statistics of random lasers with resonant feedback. With an increase of the pump intensity, the photon number distribution in a single mode changes continuously from Bose-Einstein distribution at the threshold to Poisson distribution well above the threshold. The second-order correlation coefficient drops gradually from 2 to 1. By comparing the photon statistics of a random laser with resonant feedback and that of a random laser with nonresonant feedback, we illustrate very different lasing mechanisms for the two types of random lasers.

Cao, H.; Ling, Y.; Xu, J. Y.; Cao, C. Q.; Kumar, Prem

2001-05-01

16

Photon statistics of random lasers with resonant feedback.  

PubMed

We have measured the photon statistics of random lasers with resonant feedback. With an increase of the pump intensity, the photon number distribution in a single mode changes continuously from Bose-Einstein distribution at the threshold to Poisson distribution well above the threshold. The second-order correlation coefficient drops gradually from 2 to 1. By comparing the photon statistics of a random laser with resonant feedback and that of a random laser with nonresonant feedback, we illustrate very different lasing mechanisms for the two types of random lasers. PMID:11384274

Cao, H; Ling, Y; Xu, J Y; Cao, C Q; Kumar, P

2001-05-14

17

Odd numbers of photons and teleportation  

SciTech Connect

Several teleportation protocols, namely those using entangled coherent states, entangled squeezed states, and the single-photon Einstein-Podolsky-Rosen state, are all shown to be particular instances of a more general scheme that relies on the detection of an odd number of photons.

Enk, S.J. van [Bell Labs, Lucent Technologies, 600-700 Mountain Avenue, Murray Hill, New Jersy 07974 (United States)

2003-02-01

18

Quantum random-number generator based on a photon-number-resolving detector  

NASA Astrophysics Data System (ADS)

We demonstrated a high-efficiency quantum random number generator which takes inherent advantage of the photon number distribution randomness of a coherent light source. This scheme was realized by comparing the photon flux of consecutive pulses with a photon number resolving detector. The random bit generation rate could reach 2.4 MHz with a system clock of 6.0 MHz, corresponding to a random bit generation efficiency as high as 40%. The random number files passed all the stringent statistical tests.

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

2011-02-01

19

Quantum random-number generator based on a photon-number-resolving detector  

SciTech Connect

We demonstrated a high-efficiency quantum random number generator which takes inherent advantage of the photon number distribution randomness of a coherent light source. This scheme was realized by comparing the photon flux of consecutive pulses with a photon number resolving detector. The random bit generation rate could reach 2.4 MHz with a system clock of 6.0 MHz, corresponding to a random bit generation efficiency as high as 40%. The random number files passed all the stringent statistical tests.

Ren Min; Wu, E; Liang Yan; Jian Yi; Wu Guang; Zeng Heping [State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062 (China)

2011-02-15

20

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

21

Photon-number-limiting device for nonclassical light generation  

SciTech Connect

We present a scheme for the realization of a stationary source of nonclassical light, which approximates very well a continuous single-photon source. It consists of a single four-level atom trapped inside a high-finesse optical cavity and Raman coupled to a cavity mode. A selectivity mechanism, based on a field-dependent Stark shift of electronic levels, prevents the occupation of two or more photon states of the quantized mode being excited. The output light of such a source exhibits sub-Poissonian photon-number statistics and antibunching behavior.

Matos Filho, R. L. de; Zagury, N. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972, Rio de Janeiro (Brazil); Retamal, J. C. [Departamento de Fisica, Universidad de Santiago de Chile, Casilla 307, Correo 2, Santiago (Chile)

2006-01-15

22

Counting statistics of collective photon transmissions  

SciTech Connect

We theoretically study cooperative effects in the steady-state transmission of photons through a medium of N radiators. Using methods from quantum transport, we find a cross-over in scaling from N to N{sup 2} in the current and to even higher powers of N in the higher cumulants of the photon counting statistics as a function of the tunable source occupation. The effect should be observable for atoms confined within a nano-cell with a pumped optical cavity as photon source. - Highlights: > Super-radiance transfers to super-transmittance in steady-state transport. > Higher cumulants are much more sensitive indicators for collective behavior than the first cumulant. > Effects should be measurable by pumped-cavity experiment.

Vogl, M., E-mail: malte.vogl@tu-berlin.de; Schaller, G., E-mail: gernot.schaller@tu-berlin.de; Brandes, T.

2011-10-15

23

Photon-Number Distribution and Wigner Function of Generalized Photon-Modulated Coherent State  

NASA Astrophysics Data System (ADS)

In this paper, we present the generalized photon-modulated coherent state (GPMCS) generated by repeatedly operating the combination of Bosonic creation and annihilation operators on the coherent state. It is found that the GPMCS is a Hermite-excited coherent state and its normalization factor is related to single-variable Hermite polynomials. Furthermore, some significant quantum statistical properties of the GPMCS are investigated, such as photon-number distribution (PND) and the Wigner function (WF). We find that the WF of the GPMCS has negative values when the generalized photon-modulation exists, which implies the nonclassical properties of the GPMCS.

Zhou, Jun; Wang, Shuai; Song, Jun; Fan, Hong-Yi

24

Highly nonclassical photon statistics in parametric down-conversion  

SciTech Connect

We use photon counters to obtain the joint photon-counting statistics from twin-beam nondegenerate parametric down-conversion, and we demonstrate directly, and with no auxiliary assumptions, that these twin beams are nonclassical.

Waks, Edo; Diamanti, Eleni; Yamamoto, Yoshihisa [E. L. Ginzton Laboratories, Stanford University, Stanford, California 94305 (United States); Sanders, Barry C. [Institute for Quantum Information Science, University of Calgary, Alberta, T2N 1N4 (Canada); Centre for Quantum Computer Technology, Macquarie University, New South Wales 2109 (Australia)

2006-03-15

25

Statistics of fluorescent photons emitted near a phase conjugator  

NASA Astrophysics Data System (ADS)

Temporal photon correlations and photon count statistics of fluorescence radiation, emitted by an atom in the vicinity of a phase conjugator, are considered. The fluorescent intensity and the two-photon correlation function are expressed in terms of photon emission operators. An explicit evaluation shows their dependence on the phase-conjugate reflectivity of the surface. The variance of the photon count distribution for long counting times is expressed in terms of the Q-factor, which is evaluated as a function of the reflectivity. It appears that for a reflectivity larger than unity, the photon correlation displays antibunching and the statistics are sub-poissonian.

Arnoldus, Henk F.; George, Thomas F.; Um, Chung I.

1992-01-01

26

Statistical fitting accuracy in photon correlation spectroscopy  

NASA Astrophysics Data System (ADS)

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.

1993-07-01

27

Photon statistics of radiation produced by destructive interference of two-photon absorbed light  

Microsoft Academic Search

Extending our work on the enhancement of photon antibunching we investigate the photon statistics after interference of a two-photon absorbed beam with a coherent one. The interference is calculated in the polarization picture but the equivalence to an interferometer is shown. We use the asymptotic behaviour during two-photon absorption and apply also approximate equations to study the system in the

A. Bandilla; H.-H. Ritze

1980-01-01

28

Photon-number discrimination without a photon counter and its application to reconstructing non-Gaussian states  

SciTech Connect

The nonlinearity of a conditional photon-counting measurement can be used to ''de-Gaussify'' a Gaussian state of light. Here we present and experimentally demonstrate a technique for photon-number resolution using only homodyne detection. We then apply this technique to inform a conditional measurement, unambiguously reconstructing the statistics of the non-Gaussian one- and two-photon-subtracted squeezed vacuum states. Although our photon-number measurement relies on ensemble averages and cannot be used to prepare non-Gaussian states of light, its high efficiency, photon-number-resolving capabilities, and compatibility with the telecommunications band make it suitable for quantum-information tasks relying on the outcomes of mean values.

Chrzanowski, H. M.; Bernu, J.; Sparkes, B. M.; Hage, B.; Lam, P. K.; Symul, T. [Centre for Quantum Computation and Communication Technology, Quantum Optics group, Department of Quantum Science, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia); Lund, A. P. [Centre for Quantum Computation and Communication Technology, Centre for Quantum Dynamics, Griffith University, Nathan QLD 4111 (Australia); Ralph, T. C. [Centre for Quantum Computation and Communication Technology, Department of Physics, University of Queensland, St. Lucia QLD 4072 (Australia)

2011-11-15

29

Steering photon statistics in single quantum dots: From one- to two-photon emission  

NASA Astrophysics Data System (ADS)

We present a combined experimental and theoretical study of two-photon emission from the biexciton cascade in single GaN quantum dots. By changing the biexciton binding energy, pump power, and temperature, the balance between the one- and two-photon decay processes is controlled in this four-level system, which drastically affects the photon statistics of the resulting emission. As the most pronounced feature of this interplay we observe a bunching phenomenon and a transition from sub- to super-Poissonian photon statistics, originating from the complex nature of the biexciton cascade. This work highlights how photon statistics can be steered between one- and two-photon processes towards an increased, bunched two-photon emission probability up to 50 K with the perspective for efficient photon pair generation in the UV spectral range.

Callsen, G.; Carmele, A.; Hönig, G.; Kindel, C.; Brunnmeier, J.; Wagner, M. R.; Stock, E.; Reparaz, J. S.; Schliwa, A.; Reitzenstein, S.; Knorr, A.; Hoffmann, A.; Kako, S.; Arakawa, Y.

2013-06-01

30

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

31

Photon statistics of light fields based on single-photon-counting modules  

SciTech Connect

Single-photon-counting modules (SPCM's), with their high quantum efficiency, have been widely used to investigate effectively the photon statistics of various light sources, such as the single-photon state and emission light from controlled molecules, atoms, and quantum dots. However, such SPCM's cannot distinguish the arrivals of one photon and two (or more than two) photons at a moment, which makes measurement correction in real experiments. We analyze the effect of SPCM's on photon statistics based on the Hanbury-Brown-Twiss configuration when the total efficiency and background are considered, and it shows that the measured second-order degree of coherence and Mandel Q factor for different quantum states, including single-photon states and squeezed vacuum states, are corrected in different forms. A way of determining the squeezing of a squeezed vacuum state based on single-photon detection is presented.

Li, G.; Zhang, T.C.; Li, Y.; Wang, J.M. [State Key Laboratory of Quantum Optics and Quantum Optics Devices and Institute of Opto-Electronics, Shanxi University, Taiyuan, 030006 (China)

2005-02-01

32

Photon statistics of atomic fluorescence after {pi}-pulse excitation  

SciTech Connect

The photon statistics of atomic fluorescence after {pi}-pulse excitation is investigated in a system in which the input and output ports are connected to an atom. Since spontaneous decay during input pulse excitation occurs, the output pulse generally contains a multiphoton component with a certain probability. We quantitatively evaluate the probability of the output pulse containing multiple photons and determine the conditions for ideal single-photon generation.

Yoshimi, Kazuyoshi [College of Liberal Arts and Sciences, Tokyo Medical and Dental University, Ichikawa, Chiba 272-0827 (Japan); Koshino, Kazuki [College of Liberal Arts and Sciences, Tokyo Medical and Dental University, Ichikawa, Chiba 272-0827 (Japan); PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan)

2010-09-15

33

Self consistent, absolute calibration technique for photon number resolving detectors.  

PubMed

Well characterized photon number resolving detectors are a requirement for many applications ranging from quantum information and quantum metrology to the foundations of quantum mechanics. This prompts the necessity for reliable calibration techniques at the single photon level. In this paper we propose an innovative absolute calibration technique for photon number resolving detectors, using a pulsed heralded photon source based on parametric down conversion. The technique, being absolute, does not require reference standards and is independent upon the performances of the heralding detector. The method provides the results of quantum efficiency for the heralded detector as a function of detected photon numbers. Furthermore, we prove its validity by performing the calibration of a Transition Edge Sensor based detector, a real photon number resolving detector that has recently demonstrated its effectiveness in various quantum information protocols. PMID:22109203

Avella, A; Brida, G; Degiovanni, I P; Genovese, M; Gramegna, M; Lolli, L; Monticone, E; Portesi, C; Rajteri, M; Rastello, M L; Taralli, E; Traina, P; White, M

2011-11-01

34

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

35

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

36

Photon-number-resolved heralded-photon source for improved quantum key distribution  

SciTech Connect

We have suppressed multiphoton probability of a heralded-photon source, which is vital for quantum key distribution with a higher secure key generation rate. It is accomplished by utilizing a practical photon-number-resolving detector for triggering resulting in an important step for improved practical quantum key distribution. Heralded-photon source and a practical photon-number-resolving detector capable of real-time processed multiphoton rejection are stably operable at room temperature and enable us to generate a secure key at a distance as long as an ideal single photon source is used.

Horikiri, Tomoyuki [Department of Physics, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan); Institute of Laser Science and Department of Applied Physics and Chemistry, University of Telecommunications, Chofu-ga-oka 1-5-1, Chofu, Tokyo 182-8585 (Japan); Takeno, Yuishi [Department of Physics, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan); Yabushita, Atsushi [Department of Electrophysics, Faculty of Science, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu, Taiwan 300 (China); Kobayashi, Takayoshi [ICORP, JST, 4-1-8 Honcho, Kawaguchi, Saitama (Japan); Institute of Laser Science and Department of Applied Physics and Chemistry, University of Telecommunications, Chofu-ga-oka 1-5-1, Chofu, Tokyo 182-8585 (Japan); Department of Electrophysics, Faculty of Science, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu, Taiwan 300 (China); Institute of Laser Engineering, Osaka University, Yamadagaoka 2-6, Suita, Osaka 565-0871 (Japan)

2007-07-15

37

Some remarks on photons statistics in the LS-counter.  

PubMed

The available experimental data relating to processes in the liquid scintillation (LS) detector that lead to fluorescence have been analysed and the evaluated number of photons created are given. The evaluated global distribution of photons emitted from the LS-vial in the case of low-energy emitters is presented. The global distribution of photons is well fitted by the Polya distribution. PMID:18367402

Broda, R

2008-02-13

38

Photon-number squeezing in circuit quantum electrodynamics.  

PubMed

A superconducting single-electron transistor (SSET) coupled to an anharmonic oscillator, e.g., a Josephson junction-L-C circuit, can drive the latter to a nonequilibrium photon-number distribution. By biasing the SSET at the Josephson quasiparticle cycle, cooling of the oscillator as well as a laserlike enhancement of the photon number can be achieved. Here, we show that the cutoff in the quasiparticle tunneling rate due to the superconducting gap, in combination with the anharmonicity of the oscillator, may create strongly squeezed photon-number distributions. For low dissipation in the oscillator, nearly pure Fock states can be produced. PMID:18851559

Marthaler, M; Schön, Gerd; Shnirman, Alexander

2008-09-29

39

Is the number of photons conserved in an expanding universe?  

Microsoft Academic Search

A Friedman-like scenario is described in which due to the direct coupling of electromagnetic fields to spacetime curvature-the total number of photons comprised in the Universe at a given epoch changes as the Universe expands. The photon number distribution function, according to this scenario, acquires an explicit dependence on a non-vanishing chemical potential term which accounts for the occurrence of

M. Novello; L. A. R. Oliveira; J. M. Salim

1990-01-01

40

Statistical properties and decoherence in a thermal channel of photon-excited squeezed coherent states  

NASA Astrophysics Data System (ADS)

In this paper, photon-excited squeezed coherent states (PESCS) are studied theoretically by adding a photon to the squeezed coherent states repeatedly. By taking advantage of the normally ordered form of the density operator for PESCS, the analytical expressions of the normalization constant, Mandel Q-parameter, photon-number distribution, quadrature squeezing and Wigner function are derived and discussed in detail, and from these the sub-Poissonian photon statistics, photon-number oscillations, negative value of quadrature squeezing, and partial negativity and non-Gaussian distribution of a Wigner function are demonstrated, respectively. These criteria well exhibit the highly nonclassical properties and non-Gaussianity of PESCS. In addition, by deriving the normally ordered form of the density operator and Wigner function for PESCS in a thermal channel, the decoherence process of PESCS is analyzed both analytically and numerically.

Wang, Zhen; Meng, Xiang-guo; Fan, Hong-yi

2013-04-01

41

Is the number of photons conserved in an expanding universe  

NASA Astrophysics Data System (ADS)

A Friedman - like scenario in which, due to gravitational interaction, the total number of photons existing in the Universe changes as the Universe expands, is described. The photon number distribution function, in thermal equilibrium, exhibits an explicit dependence on a non-vanishing chemical potential term. This non-null value for the chemical potential of the photon is due to the presence of tidal effects, arising from the direct coupling of the photons - which, in a gravitational field, should not be treated as idealized point-like objects - to the curvature of space-time. As a result, the ratio n(gamma)/nB between the numbers of photons and baryons in the Universe is shown to be not a constant, but rather a function of cosmic time, vanishing when the singularity of the standard FRW model is reached. In consequence, some of the supposed fundamental problems of standard Cosmology (e.g., the explanation of the constancy of the ration n(gamma)/nB and thus of the origin of the total amount of entropy observed today are but apparent ones in the present scenario, and may be ipso facto solved.

Novello, M.; Oliveira, L. A. R.; Salim, J. M.

1988-02-01

42

Photon Statistics for Single-Molecule Nonlinear Spectroscopy  

NASA Astrophysics Data System (ADS)

We develop the theory of nonlinear spectroscopy for a single molecule undergoing stochastic dynamics and interacting with a sequence of two laser pulses. We find general expressions for the photon counting statistics and the exact solution to the problem for the Kubo-Anderson process. In the limit of impulsive pulses the information on the photon statistics is contained in the molecule’s dipole correlation function. The selective limit, the semiclassical approximation, and the fast modulation limit exhibit rich general behaviors of this new type of spectroscopy. We show how the design of external fields leads to insights on ultrafast dynamics of individual molecules that are different from those found for an ensemble.

Shikerman, F.; Barkai, E.

2007-11-01

43

Decoy state quantum key distribution with a photon number resolved heralded single photon source  

NASA Astrophysics Data System (ADS)

Recently a long distance and high key rate quantum key distribution (QKD) has become possible by the idea of the decoy state method. We show that a longer distance QKD is possible by utilizing a heralded single photon source (utilizing spontaneous parametric down-conversion) as a source instead of a weak coherent pulse (WCP) as proposed in the original decoy state method. Moreover, the key rate is improved by utilizing a presently available photon number resolving detector as a trigger detector of the heralded single photon source and it is shown to approach the key rate of the WCP.

Horikiri, Tomoyuki; Kobayashi, Takayoshi

2006-03-01

44

Experimental generation of optical "Schrödinger cats" from photon number states  

NASA Astrophysics Data System (ADS)

A "Schrödinger cat" state of free-propagating light can be defined as a quantum superposition of well separated coherent states. 1, 2 We demonstrated, theoretically and experimentally, a protocol which allows to generate arbitrarily large squeezed Schrödinger cat states, using a homodyne detection and photon number states as resources. We implemented this protocol experimentally with light pulses containing two photons, producing a squeezed Schrödinger cat state with a negative Wigner function. This state clearly presents several quantum phase-space interference fringes between the "dead" and "alive" components, and it is large enough to become useful for experimental tests of quantum theory and quantum information processing.

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

2007-09-01

45

Entangled photon electron states and the number-phase minimum uncertainty states of the photon field  

Microsoft Academic Search

The exact analytic solutions of the energy eigenvalue equation of the system consisting of a free electron and one mode of the quantized radiation field are used for studying the physical meaning of a class of number-phase minimum uncertainty states. The states of the mode which minimize the uncertainty product of the photon number and the Suskind and Glogower (1964

S. Varró

2008-01-01

46

Direct Measurement of the Photon Statistics of a Triggered Single Photon Source  

NASA Astrophysics Data System (ADS)

We studied intensity fluctuations of a single photon source relying on the pulsed excitation of the fluorescence of a single molecule at room temperature. We directly measured the Mandel parameter Q(T) over 4orders of magnitude of observation time scale T by recording every photocount. On time scale of a few excitation periods, sub-Poissonian statistics is clearly observed and the probablility of two-photons events is 10times smaller than Poissonian pulses. On longer times, blinking in the fluorescence, due to the molecular triplet state, produces an excess of noise.

Treussart, F.; Alléaume, R.; Le Floc'h, V.; Xiao, L. T.; Courty, J.-M.; Roch, J.-F.

2002-08-01

47

Direct measurement of the photon statistics of a triggered single photon source.  

PubMed

We studied intensity fluctuations of a single photon source relying on the pulsed excitation of the fluorescence of a single molecule at room temperature. We directly measured the Mandel parameter Q(T) over 4 orders of magnitude of observation time scale T by recording every photocount. On time scale of a few excitation periods, sub-Poissonian statistics is clearly observed and the probablility of two-photons events is 10 times smaller than Poissonian pulses. On longer times, blinking in the fluorescence, due to the molecular triplet state, produces an excess of noise. PMID:12190402

Treussart, F; Alléaume, R; Le Floc'h, V; Xiao, L T; Courty, J-M; Roch, J-F

2002-08-13

48

Theory of photon statistics and optical coherence in a multiple-scattering random-laser medium  

NASA Astrophysics Data System (ADS)

We derive the photon-number probability distribution and the resulting degree of second-order optical coherence for light emission from a uniformly distributed active species within a multiple-light-scattering medium. This is obtained from a master equation describing the probability distribution for photons in the vicinity of position r, traveling with a wave vector k, related, in turn, to a coarse-grained average of the optical Wigner coherence function. Using a simple model for isotropic, spatially uncorrelated scatterers, this reduces to a generalization of the master equation of a conventional laser in which the medium behaves like a random collection of low-quality factor cavities that are coupled by photon diffusion between a given cavity and its neighbors. Laserlike coherence, on average, is obtained in the random laser above a specific pumping threshold. Photon-number statistics above and below the lasing threshold are computed by first assuming that the atomic response to the local electromagnetic fields is nearly instantaneous. Corrections to this simple model, arising from nonadiabatic atomic dynamics, are then estimated. The dependence of the photon statistics on scatterer density, gain concentration, and position within a sample reveal that, on average, increase of the scattering strength (decrease of the photon transport mean free path) in the medium leads to a sharper peak in the local photon-number distribution, characteristic of increased local coherence in the optical field. We also evaluate the coherence of the output field at points outside the random-laser medium. This is a weighted average of radiation emitted at different positions in the sample, exhibiting varying degrees of coherence due to variations in the local pumping intensity.

Florescu, Lucia; John, Sajeev

2004-04-01

49

Theory of photon statistics and optical coherence in a multiple-scattering random-laser medium.  

PubMed

We derive the photon-number probability distribution and the resulting degree of second-order optical coherence for light emission from a uniformly distributed active species within a multiple-light-scattering medium. This is obtained from a master equation describing the probability distribution for photons in the vicinity of position r, traveling with a wave vector k, related, in turn, to a coarse-grained average of the optical Wigner coherence function. Using a simple model for isotropic, spatially uncorrelated scatterers, this reduces to a generalization of the master equation of a conventional laser in which the medium behaves like a random collection of low-quality factor cavities that are coupled by photon diffusion between a given cavity and its neighbors. Laserlike coherence, on average, is obtained in the random laser above a specific pumping threshold. Photon-number statistics above and below the lasing threshold are computed by first assuming that the atomic response to the local electromagnetic fields is nearly instantaneous. Corrections to this simple model, arising from nonadiabatic atomic dynamics, are then estimated. The dependence of the photon statistics on scatterer density, gain concentration, and position within a sample reveal that, on average, increase of the scattering strength (decrease of the photon transport mean free path) in the medium leads to a sharper peak in the local photon-number distribution, characteristic of increased local coherence in the optical field. We also evaluate the coherence of the output field at points outside the random-laser medium. This is a weighted average of radiation emitted at different positions in the sample, exhibiting varying degrees of coherence due to variations in the local pumping intensity. PMID:15169114

Florescu, Lucia; John, Sajeev

2004-04-14

50

A fast random number generator with good statistical properties  

Microsoft Academic Search

Recently,P. A. Lewis, A. S. Goodman, andJ. M. Miller carried out extensive statistical tests on a random number generator of congruential type [3]. They showed that this generator has good statistical properties. Based on a careful analysis of the number theoretical properties of a class of generators, of which the above is a member, we have significantly increased its speed.

Fred G. Gustavson; Werner Liniger

1970-01-01

51

Statistical analysis of dark noise in photon imaging system  

NASA Astrophysics Data System (ADS)

A photon imaging system (PIS), which consists of object lens, micro-channel plate (MCP), photomultiplier tube, relay lens, CCD camera and image acquisition system is recently constructed. The dark noise of the whole imaging system has been studied by statistical analysis method. The hypothesis tests method is used to analyze statistical parameters of dark noise. In this test, the Chi-square goodness-of-fit test method is employed to determine which distribution the acquired image information is fit for. Subsequently, the section estimation is used to confirm threshold for spatial denoising process. In order to overcome the effects of the non-uniformity for PIS, we propose a new method to analyze above processes. In this method the image acquired by PIS was divided into many segments, their statistical characters have been studied respectively and the statistical parameters of the noise for the different segments are analyzed based on above method. For the aim of analyzing above acquired statistical parameters and obtaining the relationship in terms of the different operating conditions of the system, several experiments have been implemented and experiment results also be presented.

Zhao, Lei; Yu, Xin; Chen, Yi-nan

2008-03-01

52

Enhancement of Photon Number Reflected by the Relativistic Flying Mirror  

NASA Astrophysics Data System (ADS)

Laser light reflection by a relativistically moving electron density modulation (flying mirror) in a wake wave generated in a plasma by a high intensity laser pulse is investigated experimentally. A counterpropagating laser pulse is reflected and upshifted in frequency with a multiplication factor of 37-66, corresponding to the extreme ultraviolet wavelength. The demonstrated flying mirror reflectivity (from 3×10-6 to 2×10-5, and from 1.3×10-4 to 0.6×10-3, for the photon number and pulse energy, respectively) is close to the theoretical estimate for the parameters of the experiment.

Kando, M.; Pirozhkov, A. S.; Kawase, K.; Esirkepov, T. Zh.; Fukuda, Y.; Kiriyama, H.; Okada, H.; Daito, I.; Kameshima, T.; Hayashi, Y.; Kotaki, H.; Mori, M.; Koga, J. K.; Daido, H.; Faenov, A. Ya.; Pikuz, T.; Ma, J.; Chen, L.-M.; Ragozin, E. N.; Kawachi, T.; Kato, Y.; Tajima, T.; Bulanov, S. V.

2009-12-01

53

Enhancement of Photon Number Reflected by the Relativistic Flying Mirror  

SciTech Connect

Laser light reflection by a relativistically moving electron density modulation (flying mirror) in a wake wave generated in a plasma by a high intensity laser pulse is investigated experimentally. A counterpropagating laser pulse is reflected and upshifted in frequency with a multiplication factor of 37-66, corresponding to the extreme ultraviolet wavelength. The demonstrated flying mirror reflectivity (from 3x10{sup -6} to 2x10{sup -5}, and from 1.3x10{sup -4} to 0.6x10{sup -3}, for the photon number and pulse energy, respectively) is close to the theoretical estimate for the parameters of the experiment.

Kando, M.; Pirozhkov, A. S.; Kawase, K.; Esirkepov, T. Zh.; Fukuda, Y.; Kiriyama, H.; Okada, H.; Daito, I.; Kameshima, T.; Hayashi, Y.; Kotaki, H.; Mori, M.; Koga, J. K.; Daido, H.; Faenov, A. Ya.; Pikuz, T.; Ma, J.; Chen, L.-M.; Kawachi, T.; Kato, Y. [Advanced Photon Research Center, JAEA, 8-1-7 Umemidai, Kizugawa, Kyoto 619-0215 (Japan)

2009-12-04

54

Gentile statistics with a large maximum occupation number  

NASA Astrophysics Data System (ADS)

In Gentile statistics the maximum occupation number can take on unrestricted integers: 1statistics will reduce to Bose-Einstein statistics when n equals the total number of particles in the system N. In this paper, we will show that this statement is valid only when the fugacity z<1 nevertheless, if z>1 the Bose-Einstein case is not recovered from Gentile statistics as n goes to N. Attention is also concentrated on the contribution of the ground state which was ignored in related literature. The thermodynamic behavior of a ?-dimensional Gentile ideal gas of particle of dispersion E=ps/2m, where ? and s are arbitrary, is analyzed in detail. Moreover, we provide an alternative derivation of the partition function for Gentile statistics.

Dai, Wu-Sheng; Xie, Mi

2004-02-01

55

Lacunary statistical convergence of sequences of fuzzy numbers  

Microsoft Academic Search

The sequence X = {Xk} of fuzzy numbers is statistically convergent to the fuzzy number X0 provided that for each ? ? 0limln{the number ofk?n:d(Xk,X0)??}=0.In this paper we study a related concept of convergence in which the set {k: k?n} is replaced by {k: kr?1 ? k ? kr} for some lacunary sequence {kr}. Also we introduce the concept of

Fatih Nuray

1998-01-01

56

Double galaxy redshifts and the statistics of small numbers  

NASA Astrophysics Data System (ADS)

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

1989-09-01

57

Single molecule analysis of DNA synthesis using non-classical photon statistics  

NASA Astrophysics Data System (ADS)

The fidelity of DNA replication is important for maintaining cell function and survival. DNA polymerases play a crucial role in the processes of replication and repair. Using non-classical photon emission from fluorescently labeled incorporated nucleotides, we have developed a procedure for monitoring the action of polymerases on single molecules of DNA. We previously showed fluorescence photon antibunching spectroscopy allows for the quantifying of the number of fluorescent emitters present on a single DNA molecule. Images of the synthesized DNA were collected using scanning confocal microscopy, and the second-order correlation function, g2(t), was measured for each individual DNA molecule, with nanosecond resolution. Analysis of this function revealed the number of specific nucleotides selectively labeled with a fluorescent dye. We present the statistics showing the level of polymerase activity. We will also show the usefulness of this method for studying how different DNA polymerases interact and cope with different types of DNA damage.

Fore, S.; Yeh, Y.; Huser, T.; Balhorn, R.; Cosman, M.; Laurence, T.

2004-03-01

58

Generation of optical `Schrödinger cats' from photon number states  

NASA Astrophysics Data System (ADS)

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.

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

2007-08-01

59

Statistical tests of the IBM PC pseudorandom number generator.  

PubMed

The widespread use of IBM personal computers in biomedical research and medical practice is evidenced by a variety of journal articles. Many of the application programs are written in the BASIC language, they model a stochastic process, and they depend on the Microsoft random number generator. Unfortunately, the Microsoft generator has exhibited a number of flaws including, for some seeds, a lack of uniformity of generated sequences of numbers, and serial correlation within such sequences. This paper provides evidence of these problems for several seeds, and provides suggestions for acceptable seeds which ensure that the generated sequences of numbers pass two fundamental statistical tests for randomness. PMID:2582745

Gleason, J M

1989-09-01

60

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

61

Particle number counting statistics in ideal Bose gases  

Microsoft Academic Search

We discuss the exact particle number counting statistics of degenerate ideal Bose gases in the microcanonical, canonical, and grand-canonical ensemble, respectively, for various trapping potentials. We then invoke the Maxwell's Demon ensemble [Navez et el., Phys. Rev. Lett. (1997)] and show that for large total number of particles the root-mean-square fluctuation of the condensate occupation scales n0 \\/ [T=Tc] r

Christoph Weiss; Martin Wilkens

1997-01-01

62

Submillimeter Number Counts from Statistical Analysis of BLAST Maps  

Microsoft Academic Search

We describe the application of a statistical method to estimate submillimeter galaxy number counts from confusion-limited observations by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST). Our method is based on a maximum likelihood fit to the pixel histogram, sometimes called \\

Guillaume Patanchon; Peter A. R. Ade; James J. Bock; Edward L. Chapin; Mark J. Devlin; Simon R. Dicker; Matthew Griffin; Joshua O. Gundersen; Mark Halpern; Peter C. Hargrave; David H. Hughes; Jeff Klein; Gaelen Marsden; Philip Mauskopf; Lorenzo Moncelsi; Calvin B. Netterfield; Luca Olmi; Enzo Pascale; Marie Rex; Douglas Scott; Christopher Semisch; Nicholas Thomas; Matthew D. P. Truch; Carole Tucker; Gregory S. Tucker; Marco P. Viero; Donald V. Wiebe

2009-01-01

63

Quantum communication with photon-number entangled states and realistic photodetection  

NASA Astrophysics Data System (ADS)

We address the effects of realistic photodetection, with nonunit quantum efficiency and background noise (dark counts), on the performances of quantum communication schemes based on photon-number entangled states (PNES). We consider channels based on Gaussian twin-beam states (TWB) and non-Gaussian two-mode coherent states (TMC) and evaluate the channel capacity by optimizing the bit discrimination threshold. We found that TWB-based channels are more robust against noise than TMC-based ones and that this result is almost independent on the statistics of dark counts.

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

2010-03-01

64

Photon-Number Distribution and Wigner Function of Generalized Squeezed Thermal State  

NASA Astrophysics Data System (ADS)

In this paper, we present the density operator of the generalized squeezed thermal state (GSTS) and obtain its normal ordering form by virtue of the technique of integration within an ordered product of operators and the Weyl ordering invariance under similarity transformations. Some significant quantum statistical properties of the GSTS are investigated, such as the photon-number distribution (PND) and the Wigner function (WF). It is found that the PND of the GSTS is a Legendre polynomial, and its squeezed vacuum oscillations imply the nonclassicality, as well as the GSTS whose WF has no negative region is indeed a special type of nonclassical state.

Zhou, Jun; Song, Jun; Yuan, Hao; Zhang, Bo; Xie, Chuan-Mei; Fan, Hong-Yi

2012-09-01

65

Photon statistics of amplified spontaneous emission in a dense wavelength-division multiplexing regime  

NASA Astrophysics Data System (ADS)

The photon statistics of amplified spontaneous emission in the few-modes regime and in single mode, conditions that are typical of dense wavelength-division multiplexing transmission, have been experimentally proved by direct detection. The dependence of the degeneracy factor for the Bose-Einstein distribution on the degree of second-order coherence of light is stated. The theoretical dependence of the number of amplified spontaneous emission modes on the ratio between the optical channel and the detector bandwidths has also been confirmed by experiments, thus quantifying the loss of validity of asymptotic approximations when they are extended to the few-modes regime.

Pietralunga, Silvia M.; Martelli, Paolo; Martinelli, Mario

2003-02-01

66

Photon statistics of amplified spontaneous emission in a dense wavelength-division multiplexing regime.  

PubMed

The photon statistics of amplified spontaneous emission in the few-modes regime and in single mode, conditions that are typical of dense wavelength-division multiplexing transmission, have been experimentally proved by direct detection. The dependence of the degeneracy factor for the Bose-Einstein distribution on the degree of second-order coherence of light is stated. The theoretical dependence of the number of amplified spontaneous emission modes on the ratio between the optical channel and the detector bandwidths has also been confirmed by experiments, thus quantifying the loss of validity of asymptotic approximations when they are extended to the few-modes regime. PMID:12656315

Pietralunga, Silvia M; Martelli, Paolo; Martinelli, Mario

2003-02-01

67

Time-dependent photon number discrimination of InGaAs/InP avalanche photodiode single-photon detector.  

PubMed

We investigated the photon-number-resolving (PNR) performance of the InGaAs/InP avalanche photodiode (APD) as a function of the electric gate width and the photon arrival time. The optimal electric gate width was around 1 ns for PNR measurements in our experiment, which provided a PNR capability up to three photons per pulse when the detection efficiency was ~20%. And the dependence of the PNR performance on the arrival time of the photons showed that the photon number could be better resolved if the photons arrived on the rising edge of the electric gate than on the falling edge. In addition, we found that with the increase of the electric gate width, PNR performance got worse. The observation would be helpful for improving the PNR performance of the InGaAs/InP APD in the gated mode. PMID:21221161

Jian, Yi; Wu, E; Chen, Xiuliang; Wu, Guang; Zeng, Heping

2011-01-01

68

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

69

Statistical issues in the analysis of DNA Copy Number Variations  

PubMed Central

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.

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

2009-01-01

70

Statistical properties of a generalized photon-modulated thermal state  

Microsoft Academic Search

In this paper, we introduce a new kind of quantum state, generalized photon-modulated thermal states (GPMTS), which are obtained by repeatedly acting the superposed operation (a coherent superposition of photon subtraction and addition) on the thermal state. It is found that the normalization factor of GPMTS is a Legendre polynomial. Moreover, we present the analytical expressions of several quasi-probability distributions

Xue-Xiang Xu; Hong-Chun Yuan; Li-Yun Hu; Hong-Yi Fan

2011-01-01

71

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

72

Entanglement quantification from incomplete measurements: applications using photon-number-resolving weak homodyne detectors  

NASA Astrophysics Data System (ADS)

The certificate of success for a number of important quantum information processing protocols, such as entanglement distillation, is based on the difference in the entanglement content of the system quantum states before and after the protocol. In such cases, effective bounds need to be placed on the entanglement of non-local states consistent with statistics obtained from local measurements. In this paper, we study numerically the ability of a hybrid homodyne detector that combines phase sensitivity and photon-number resolution to set accurate bounds on the entanglement content of two-mode quadrature squeezed states without the need for full state tomography. We show that it is possible to set tight lower bounds on the entanglement of a family of two-mode degaussified states using only a few measurements. This presents a significant improvement over the resource requirements for the experimental demonstration of continuous-variable entanglement distillation, which traditionally relies on full quantum state tomography.

Puentes, Graciana; Datta, Animesh; Feito, Alvaro; Eisert, Jens; Plenio, Martin B.; Walmsley, Ian A.

2010-03-01

73

Statistical distributions of earthquake numbers: consequence of branching process  

NASA Astrophysics Data System (ADS)

We discuss various statistical distributions of earthquake numbers. Previously, we derived several discrete distributions to describe earthquake numbers for the branching model of earthquake occurrence: these distributions are the Poisson, geometric, logarithmic and the negative binomial (NBD). The theoretical model is the `birth and immigration' population process. The first three distributions above can be considered special cases of the NBD. In particular, a point branching process along the magnitude (or log seismic moment) axis with independent events (immigrants) explains the magnitude/moment-frequency relation and the NBD of earthquake counts in large time/space windows, as well as the dependence of the NBD parameters on the magnitude threshold (magnitude of an earthquake catalogue completeness). We discuss applying these distributions, especially the NBD, to approximate event numbers in earthquake catalogues. There are many different representations of the NBD. Most can be traced either to the Pascal distribution or to the mixture of the Poisson distribution with the gamma law. We discuss advantages and drawbacks of both representations for statistical analysis of earthquake catalogues. We also consider applying the NBD to earthquake forecasts and describe the limits of the application for the given equations. In contrast to the one-parameter Poisson distribution so widely used to describe earthquake occurrence, the NBD has two parameters. The second parameter can be used to characterize clustering or overdispersion of a process. We determine the parameter values and their uncertainties for several local and global catalogues, and their subdivisions in various time intervals, magnitude thresholds, spatial windows, and tectonic categories. The theoretical model of how the clustering parameter depends on the corner (maximum) magnitude can be used to predict future earthquake number distribution in regions where very large earthquakes have not yet occurred.

Kagan, Yan Y.

2010-03-01

74

Quantum Statistics of One-Photon Interaction of Light With Matter  

Microsoft Academic Search

Quantum statistics of one-photon interaction of light with matter is investigated. It is found that in general the density operator changes. For a chaotic field, however, the density operator changes only in a trivial way.

Naresh Chandra; Hari Prakash

1969-01-01

75

Biexciton quantum yield of single semiconductor nanocrystals from photon statistics  

PubMed Central

Biexciton properties strongly affect the usability of a light emitter in quantum photon sources and lasers but are difficult to measure for single fluorophores at room temperature due to luminescence intermittency and bleaching at the high excitation fluences usually required. Here, we observe the biexciton (BX) to exciton (X) to ground photoluminescence cascade of single colloidal semiconductor nanocrystals (NCs) under weak excitation in a g(2) photon correlation measurement and show that the normalized amplitude of the cascade feature is equal to the ratio of the BX to X fluorescence quantum yields. This imposes a limit on the attainable depth of photon antibunching and provides a robust means to study single emitter biexciton physics. In NC samples, we show that the BX quantum yield is considerably inhomogeneous, consistent with the defect sensitivity expected of the Auger nonradiative recombination mechanism. The method can be extended to study X,BX spectral and polarization correlations.

Nair, Gautham; Zhao, Jing; Bawendi, Moungi G

2012-01-01

76

High-efficiency quantum-nondemolition single-photon-number-resolving detector  

NASA Astrophysics Data System (ADS)

We discuss an approach to the problem of creating a photon-number-resolving detector using the giant Kerr nonlinearities available in electromagnetically induced transparency. Our scheme can implement a photon-number quantum-nondemolition measurement with high efficiency (˜99%) using fewer than 1600 atoms embedded in a dielectric waveguide.

Munro, W. J.; Nemoto, Kae; Beausoleil, R. G.; Spiller, T. P.

2005-03-01

77

Formation of ultrashort pulses with sub-Poissonian photon statistics  

SciTech Connect

A simple method for the production of ultrashort light pulses (USPs) with suppressed photon fluctuations is considered, which is based on self-phase modulation (SPM) of a USP in a nonlinear medium, say, an optical fibre and subsequent transmission of a pulse through a dispersive optical element. (this issue is dedicated to the memory of s a akhmanov)

Popescu, F; Chirkin, Anatolii S [Department of Physics, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

1999-07-31

78

Effects of propagation in air on photon statistics  

SciTech Connect

Calculations of photon counting distributions and fade probabilities are compared with measured data obtained using very weak laser pulses propagated over 10-km horizontal paths. Good agreement is obtained between theory and experiment using various simplifying assumptions and values of the refractive-index structure constant C{sup 2}{sub n} lying within an expected range.

Milonni, Peter W.

2003-01-01

79

Linear optical quantum computation with imperfect entangled photon-pair sources and inefficient non-photon-number-resolving detectors  

SciTech Connect

We propose a scheme for efficient cluster state quantum computation by using imperfect polarization-entangled photon-pair sources, linear optical elements, and inefficient non-photon-number-resolving detectors. The efficiency threshold for loss tolerance in our scheme requires the product of source and detector efficiencies should be >1/2, the best known figure. This figure applies to uncorrelated loss. We further find that the loss threshold is unaffected by correlated loss in the photon pair source. Our approach sheds new light on efficient linear optical quantum computation with imperfect experimental conditions.

Gong Yanxiao [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, 210093 (China); Key Laboratory of Quantum Information, University of Science and Technology of China, CAS, Hefei, 230026 (China); Zou Xubo; Guo Guangcan [Key Laboratory of Quantum Information, University of Science and Technology of China, CAS, Hefei, 230026 (China); Ralph, Timothy C. [Centre for Quantum Computer Technology and Physics Department, University of Queensland, Queensland 4072, Brisbane (Australia); Zhu Shining [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, 210093 (China)

2010-05-15

80

Experience and grammatical agreement: statistical learning shapes number agreement production.  

PubMed

A robust result in research on the production of grammatical agreement is that speakers are more likely to produce an erroneous verb with phrases such as the key to the cabinets, with a singular noun followed by a plural one, than with phrases such as the keys to the cabinet, where a plural noun is followed by a singular. These asymmetries are thought to reflect core language production processes. Previous accounts have attributed error patterns to a syntactic number feature present on plurals but not singulars. An alternative approach is presented in which a process similar to structural priming contributes to the error asymmetry via speakers' past experiences with related agreement constructions. A corpus analysis and two agreement production studies test this account. The results suggest that agreement production is shaped by statistical learning from past language experience. Implications for accounts of agreement are discussed. PMID:19942213

Haskell, Todd R; Thornton, Robert; Macdonald, Maryellen C

2009-11-25

81

The Numbers Game: The Top 10 Sources for Statistics.  

ERIC Educational Resources Information Center

Lists and describes the 10 best sources for answering statistical questions that are available for free or at a low cost on the World Wide Web. Statistics search tips, government publishers, almanacs, and newspapers are discussed. (LRW)

Berinstein, Paula

1998-01-01

82

Statistics for Geography Teachers: Topics in Geography, Number 2.  

ERIC Educational Resources Information Center

|This publication is designed to provide geography teachers with useful statistical information. It presents tables, maps, graphs, diagrams, and explanations of statistical data in 24 areas. The areas in which statistics are given are conversions, measurement, astronomy, time, daylight, twilight, latitude and longitude as distance, the…

National Council for Geographic Education.

83

Photon statistics of a dye laser far below threshold  

SciTech Connect

The relative mean square fluctuations <(..delta..I)/sup 2/>//sup 2/ of the intensity I of a single-mode dye laser have been measured by a photon counting technique, in the region from about threshold to intensities 1000 times below threshold. The results show a steady increase of <(..delta..I)/sup 2/>//sup 2/ from less than 1 to about 150 as is reduced, followed by a rapid drop to zero. This behavior appears to be described fairly well by an equation of motion containing both additive spontaneous emission fluctuations and multiplicative pumping fluctuations.

Lett, P.; Short, R.; Mandel, L.

1984-01-30

84

Interaction of low-energy photons with biological materials and the effective atomic number  

Microsoft Academic Search

The effective atomic numbers for total photon interaction in bone, muscle, liver, spleen, fat, and water are determined and found to decrease up to 50% as the energy increases from 10 to 200 keV. Muscle, spleen, liver, and water are found to behave in an approximately similar manner in this energy region, as far as photon interaction is concerned.

B. V. Thirumala Rao; M. L. Raju; K. L. Narasimham; K. Parthasaradhi; B. M. Rao

1985-01-01

85

Investigation of photon statistics and correlations of a dye laser  

SciTech Connect

The probability distribution p(n) for the detection of n photons emitted by a single-mode dye laser in a short time at various excitations is measured, together with the distribution of time intervals between pairs of detected photons. The first measurement yields the probability density P(I) and the moments of the light intensity I, and the second one the two-time intensity-correlation function. Measurements are also performed at three different wavelengths. P(I) is found to have a two-component structure, and the relative intensity fluctuations <(..delta..I)/sup 2/>//sup 2/ grow, apparently without limit, as the excitation tends to zero, so that no thermal state is reached. A possible explanation in terms of pumping fluctuations is discussed. The correlation function has the form of a sum of three exponential functions, and the amplitudes and decay constants of the three components are derived. The effective decay-time constant exhibits a thirteenth-power-law dependence on frequency of the laser light.

Kaminishi, K.; Roy, R.; Short, R.; Mandel, L.

1981-07-01

86

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

87

Single molecule photon emission statistics for non-Markovian blinking models  

NASA Astrophysics Data System (ADS)

The statistics of photon emission from a single molecule under continuous wave excitation are considered. In particular, we study stochastic model systems where photon emission rates evolve in time with non-Markovian dynamics. Our calculations are based on the recently introduced generalized optical Bloch equation (GBE) formalism, but with numerical complications beyond those seen in previous Markovian stochastic models. A spectral representation is introduced to facilitate the numerical solution of the GBE equations for these more challenging cases.

Zheng, Yujun; Brown, Frank L. H.

2004-08-01

88

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

89

Photon-number-discriminating detection using a quantum-dot, optically gated, field-effect transistor  

Microsoft Academic Search

Detectors with the capability to directly measure the photon number of a pulse of light enable linear optics quantum computing, affect the security of quantum communications, and can be used to characterize and herald non-classical states of light. Here, we demonstrate the photon-number-resolving capabilities of a quantum-dot, optically gated, field-effect transistor that uses quantum dots as optically addressable floating gates

M. A. Rowe; M. B. Greene; D. Rosenberg; T. E. Harvey; M. Y. Su; R. H. Hadfield; S. W. Nam; R. P. Mirin; E. J. Gansen

2007-01-01

90

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

91

Measurement of the atom number distribution in an optical tweezer using single-photon counting  

NASA Astrophysics Data System (ADS)

We demonstrate in this paper a method to reconstruct the atom number distribution of a cloud containing a few tens of cold atoms. The atoms are first loaded from a magneto-optical trap into a microscopic optical dipole trap and then released in a resonant light probe where they undergo a Brownian motion and scatter photons. We count the number of photon events detected on an image intensifier. Using the response of our detection system to a single atom as a calibration, we extract the atom number distribution when the trap is loaded with more than one atom. The atom number distribution is found to be compatible with a Poisson distribution.

Fuhrmanek, A.; Sortais, Y. R. P.; Grangier, P.; Browaeys, A.

2010-08-01

92

Statistical method for resolving the photon-photoelectron-counting inversion problem  

SciTech Connect

A statistical inversion method is proposed for the photon-photoelectron-counting statistics in quantum key distribution experiment. With the statistical viewpoint, this problem is equivalent to the parameter estimation for an infinite binomial mixture model. The coarse-graining idea and Bayesian methods are applied to deal with this ill-posed problem, which is a good simple example to show the successful application of the statistical methods to the inverse problem. Numerical results show the applicability of the proposed strategy. The coarse-graining idea for the infinite mixture models should be general to be used in the future.

Wu Jinlong [LMAM and School of Mathematical Sciences, Peking University, Beijing 100871 (China); Li Tiejun, E-mail: tieli@pku.edu.c [LMAM and School of Mathematical Sciences, Peking University, Beijing 100871 (China); Peng, Xiang, E-mail: xiangpeng@pku.edu.c [CREAM Group, State Key Laboratory of Advanced Optical Communication Systems and Networks (Peking University) and Institute of Quantum Electronics, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871 (China); Guo Hong, E-mail: hongguo@pku.edu.c [CREAM Group, State Key Laboratory of Advanced Optical Communication Systems and Networks (Peking University) and Institute of Quantum Electronics, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871 (China)

2011-02-01

93

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

94

Canadian Statistical Review. Volume 53, Number 7, July 1978.  

ERIC Educational Resources Information Center

Information on Canadian social and economic trends is presented in this statistical review. Advance information on national income and expenditure accounts for the first quarter of 1978 is provided. Characteristics of full-time university teachers from 1956-57 to 1977-78 are detailed in tables that recount such developments as the nearly six-fold…

von Zur-Muehlen, Max

1978-01-01

95

Canadian Statistical Review. Volume 53, Number 7, July 1978.  

ERIC Educational Resources Information Center

|Information on Canadian social and economic trends is presented in this statistical review. Advance information on national income and expenditure accounts for the first quarter of 1978 is provided. Characteristics of full-time university teachers from 1956-57 to 1977-78 are detailed in tables that recount such developments as the nearly six-fold…

von Zur-Muehlen, Max

1978-01-01

96

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.

97

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

98

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

99

Set partition statistics and q-Fibonacci numbers  

Microsoft Academic Search

We consider the set partition statistics ls and r b introduced by Wachs and White and investigate their distribution over set partitions that avoid certain patterns. In particular, we consider those set partitions avoiding the pattern 13=2, n.13=2\\/, and those avoiding both 13=2 and 123, n.13=2; 123\\/. We show that the distribution over n.13=2\\/ enumerates certain integer partitions, and the

Adam M. Goyt; Bruce E. Sagan

2009-01-01

100

Photon time-interval statistics applied to the analysis of laser heterodyne signal with photon counter  

NASA Astrophysics Data System (ADS)

In this paper, we report a mathematical derivation of probability density function (PDF) of time-interval between two successive photoelectrons of the laser heterodyne signal, and give a confirmation of the theoretical result by both numerical simulation and an experiment. The PDF curve of the beat signal displays a series of fluctuations, the period and amplitude of which are respectively determined by the beat frequency and the mixing efficiency. The beat frequency is derived from the frequency of fluctuations accordingly when the PDF curve is measured. This frequency measurement method still works while the traditional Fast Fourier Transform (FFT) algorithm hardly derives the correct peak value of the beat frequency in the condition that we detect 80 MHz beat signal with 8 Mcps (counts per-second) photons count rate, and this indicates an advantage of the PDF method.

Liu, Lisheng; Zhang, Heyong; Guo, Jin; Zhao, Shuai; Wang, Tingfeng

2012-08-01

101

Statistical strength of experiments to reject local realism with photon pairs and inefficient detectors  

SciTech Connect

Because of the fundamental importance of Bell's theorem, a loophole-free demonstration of a violation of local realism (LR) is highly desirable. Here, we study violations of LR involving photon pairs. We quantify the experimental evidence against LR by using measures of statistical strength related to the Kullback-Leibler (KL) divergence, as suggested by van Dam et al.[W. van Dam, R. D. Gill, and P. D. Grunwald, IEEE Trans. Inf. Theory. 51, 2812 (2005)]. Specifically, we analyze a test of LR with entangled states created from two independent polarized photons passing through a polarizing beam splitter. We numerically study the detection efficiency required to achieve a specified statistical strength for the rejection of LR depending on whether photon counters or detectors are used. Based on our results, we find that a test of LR free of the detection loophole requires photon counters with efficiencies of at least 89.71%, or photon detectors with efficiencies of at least 91.11%. For comparison, we also perform this analysis with ideal unbalanced Bell states, which are known to allow rejection of LR with detector efficiencies above 2/3.

Zhang Yanbao [Department of Physics, University of Colorado at Boulder, Colorado, 80309 (United States); Mathematical and Computational Sciences Division, National Institute of Standards and Technology, Boulder, Colorado, 80305 (United States); Knill, Emanuel; Glancy, Scott [Mathematical and Computational Sciences Division, National Institute of Standards and Technology, Boulder, Colorado, 80305 (United States)

2010-03-15

102

Characterization of Strong Light-Matter Coupling in Semiconductor Quantum-Dot Microcavities via Photon-Statistics Spectroscopy  

Microsoft Academic Search

It is shown that spectrally resolved photon-statistics measurements of the resonance fluorescence from realistic semiconductor quantum-dot systems allow for high contrast identification of the two-photon strong-coupling states. Using a microscopic theory, the second-rung resonance of Jaynes-Cummings ladder is analyzed and optimum excitation conditions are determined. The computed photon-statistics spectrum displays gigantic, experimentally robust resonances at the energetic positions of the

L. Schneebeli; M. Kira; S. W. Koch

2008-01-01

103

Theoretical modeling of single-molecule fluorescence with complicated photon statistics  

NASA Astrophysics Data System (ADS)

The use of techniques for analyzing the fluorescence photon statistics of a single molecule for modeling single-emitter dynamics is demonstrated. The photon distribution function measured in the fluorescence of a single tetra-tert-butylterrylene molecule embedded in polyisobutylene is used to devise a theoretical model for single emitters with complicated fluorescence photon statistics. Our analysis was carried out with the theoretical approach developed by Osad'ko and co-workers [J. Chem. Phys.JCPSA60021-960610.1063/1.3055287 130, 064904 (2009); J. Phys. Chem. C10.1021/jp1014093 114, 10349 (2010)] for photon distribution functions. Although the experimental data were obtained at cryogenic temperature where narrow zero-phonon lines are present, the method is based on a purely statistical approach and does not require spectrally resolved data. It can also be applied to the analysis of broad fluorescence bands as measured at room temperature. Therefore, the method has prospects for revealing the quantum dynamics of single biological objects and other single quantum emitters in ambient conditions.

Osad'ko, I. S.; Naumov, A. V.; Eremchev, I. Yu.; Vainer, Yu. G.; Kador, L.

2012-11-01

104

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

105

Statistical Tests of Some Widely Used and Recently Proposed Uniform Random Number Generators.  

National Technical Information Service (NTIS)

Several widely used uniform random number generators have been extensively subjected to three commonly used statistical tests of uniformity and randomness. The object was (1) to examine the power of these statistical tests to discriminate between good and...

G. P. Learmonth P. A. W. Lewis

1973-01-01

106

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

107

Photon-number and angular momentum asymptotics of the atom-field Hamiltonian  

Microsoft Academic Search

Asymptotic solutions to the Hamiltonian have been developed for photon numbers and angular momenta that describe an atomic assembly interacting with a single-mode quantized electromagnetic field through dipole coupling. They have been used in the formulation of a multiphoton description of the Autler-Townes effect.

Viorica N. Gheorghe; C. B. Collins

1981-01-01

108

Boosting up quantum key distribution by learning statistics of practical single-photon sources  

NASA Astrophysics Data System (ADS)

We propose a simple quantum-key-distribution (QKD) scheme for practical single-photon sources (SPSs), which works even with a moderate suppression of the second-order correlation g(2) of the source. The scheme utilizes a passive preparation of a decoy state by monitoring a fraction of the signal via an additional beam splitter and a detector at the sender's side to monitor photon-number splitting attacks. We show that the achievable distance increases with the precision with which the sub-Poissonian tendency is confirmed in higher photon-number distribution of the source, rather than with actual suppression of the multiphoton emission events. We present an example of the secure key generation rate in the case of a poor SPS with g(2)=0.19, in which no secure key is produced with the conventional QKD scheme, and show that learning the photon-number distribution up to several numbers is sufficient for achieving almost the same distance as that of an ideal SPS.

Adachi, Yoritoshi; Yamamoto, Takashi; Koashi, Masato; Imoto, Nobuyuki

2009-11-01

109

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

110

National Center for Educational Statistics Bulletin Number 8: Advance Statistics for Management.  

ERIC Educational Resources Information Center

This bulletin, produced by the National Center for Educational Statistics, releases information collected by the School Staffing Survey, Spring 1970. The data base consisted of approximately 1,200 public elementary and secondary schools. Data presented include: Environmental Health courses, Pupils Enrolled in Environmental Health Courses,…

National Center for Educational Statistics (DHEW/OE), Washington, DC.

111

Generating conditional atomic entanglement by measuring photon number in a single output channel  

SciTech Connect

The polarization analysis of quantized probe light transmitted through an atomic ensemble has been used to prepare entangled collective atomic states. In a 'balanced' detection configuration, where the difference signal from two detection ports is analyzed, the continuous monitoring of a component of the Stokes field vector provides a means for conditional projective measurements on the atomic system. Here, we make use of classical driving fields, in the pulsed regime, and of an 'unbalanced' detection setup (single detector) where the effective photon number of scattered photons is the detected observable. Conditional atomic spin squeezed states and superpositions of such squeezed states can be prepared in this manner.

Genes, C.; Berman, P. R. [Michigan Center for Theoretical Physics, FOCUS Center, and Physics Department, University of Michigan, Ann Arbor, Michigan 48109-1040 (United States)

2006-01-15

112

Direct measurement of heralded single-photon statistics from a parametric down-conversion source  

SciTech Connect

We present a full triple-coincidence analysis of photon-pair states generated by spontaneous parametric down-conversion. By increasing the coherence time of the source with the help of an intracavity setup, our measurements are not spoiled by detection time jitter. Signal-idler, but also thermal signal-signal, correlations are clearly resolved in this regime. Via introduction of an artificial coincidence window, we discuss in detail the transition to the previously studied cases where typically no single-arm correlation is observed. We investigate the heralded antibunching characteristics to show that in our system further studies of continuously generated photon states, possibly higher-photon-number entangled states, can be performed with respect to their (non)applicability in quantum information tasks.

Hoeckel, David; Koch, Lars; Benson, Oliver [Nano Optics Group, Institute of Physics, Humboldt-Universitaet zu Berlin, Newtonstrasse 15, 12489 Berlin (Germany)

2011-01-15

113

Effective atomic numbers and mass attenuation coefficients of some thermoluminescent dosimetric compounds for total photon interaction  

SciTech Connect

Effective atomic numbers for total gamma-ray interaction with some selected thermoluminescent dosimetric compounds such as barium acetate, barium sulfate, calcium carbonate, calcium sulfate, calcium sulfate dihydrate, cadmium sulfate (anhydrous), cadmium sulfate, strontium sulfate, and lithium fluoride have been calculated in the 1-keV to 20-MeV energy region. Experimental mass attenuation coefficients and effective atomic numbers for these compounds at selected photon energies of 26.3, 33.2, 59.54, and 661.6 keV have been obtained from good geometry transmission measurements and compared with theoretical values. The effect of absorption edge on effective atomic numbers and its variation with energy, and nonvalidity of the Bragg`s mixture rule at incident photon energies closer to the absorption edges of constituent elements of compounds are discussed.

Shivaramu; Amutha, R.; Ramprasath, V. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India). Safety Research and Health Physics Group

1999-05-01

114

Photon number squeezing of spectrally filtered sub-picosecond optical solitons  

NASA Astrophysics Data System (ADS)

Photon number squeezing of spectrally filtered optical solitons has been observed in the sub-picosecond regime, where the Raman effect changes the internal quantum structure of each pulse. 160 fs pulses were propagated down a 10 m optical fibre of anomalous group velocity dispersion. At energies below the soliton energy subsequent spectral filtering with an optical band-pass squeezed the directly detected photocurrent fluctuations to 3.2 ± 0.1 dB (52%) below the shot-noise limit. This implies 4.5 dB (65%) of soliton photon number squeezing, if detection losses are taken into account. Using a spectral edge filter the spectral components of the pulses are shown to contribute asymmetrically to the squeezing due to stimulated Raman scattering.

Spälter, S.; Burk, M.; Strößner, U.; Böhm, M.; Sizmann, A.; Leuchs, G.

1997-05-01

115

Discrimination of binary coherent states using a homodyne detector and a photon number resolving detector  

SciTech Connect

We investigate quantum measurement strategies capable of discriminating two coherent states probabilistically with significantly smaller error probabilities than can be obtained using nonprobabilistic state discrimination. We apply a postselection strategy to the measurement data of a homodyne detector as well as a photon number resolving detector in order to lower the error probability. We compare the two different receivers with an optimal intermediate measurement scheme where the error rate is minimized for a fixed rate of inconclusive results. The photon number resolving (PNR) receiver is experimentally demonstrated and compared to an experimental realization of a homodyne receiver with postselection. In the comparison, it becomes clear that the performance of the PNR receiver surpasses the performance of the homodyne receiver, which we prove to be optimal within any Gaussian operations and conditional dynamics.

Wittmann, Christoffer; Sych, Denis; Leuchs, Gerd [Max Planck Institute for the Science of Light, Guenther-Scharowsky-Strasse 1, Bau 24, 91058 Erlangen (Germany); Institut fuer Optik, Information und Photonik, University of Erlangen-Nuremberg, Staudtstrasse 7/B2, 91058 Erlangen (Germany); Andersen, Ulrik L. [Max Planck Institute for the Science of Light, Guenther-Scharowsky-Strasse 1, Bau 24, 91058 Erlangen (Germany); Department of Physics, Technical University of Denmark, Building 309, 2800 Kongens, Lyngby (Denmark); Takeoka, Masahiro [National Institute of Information and Communications Technology (NICT), 4-2-1 Nukui-kitamachi, Koganei, Tokyo 184-8795 (Japan)

2010-06-15

116

Quantum state engineering, purification, and number-resolved photon detection with high-finesse optical cavities  

SciTech Connect

We propose and analyze a multifunctional setup consisting of high-finesse optical cavities, beam splitters, and phase shifters. The basic scheme projects arbitrary photonic two-mode input states onto the subspace spanned by the product of Fock states |n>|n> with n=0,1,2,.... This protocol does not only provide the possibility to conditionally generate highly entangled photon number states as resource for quantum information protocols but also allows one to test and hence purify this type of quantum states in a communication scenario, which is of great practical importance. The scheme is especially attractive as a generalization to many modes allows for distribution and purification of entanglement in networks. In an alternative working mode, the setup allows for quantum nondemolition number resolved photodetection in the optical domain.

Nielsen, Anne E. B. [Lundbeck Foundation Theoretical Center for Quantum System Research, Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Muschik, Christine A.; Giedke, Geza; Vollbrecht, K. G. H. [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse, D-85748 Garching (Germany)

2010-04-15

117

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

118

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

119

Dynamics of dispersive photon-number QND measurements in a micromaser  

SciTech Connect

A numerical analysis of dispersive quantum nondemolition measurement of the photon number of a microwave cavity field is presented. Simulations show that a key property of the dispersive atom-field interaction used in Ramsey interferometry is the extremely high sensitivity of the dynamics of atomic and field states to basic parameters of the system. When a monokinetic atomic beam is sent through a microwave cavity, a qualitative change in the field state can be caused by an uncontrollably small deviation of parameters (such as atom path length through the cavity, atom velocity, cavity mode frequency detuning, or atom-field coupling constants). The resulting cavity field can be either in a Fock state or in a super-Poissonian state (characterized by a large photon-number variance). When the atoms have a random velocity spread, the field is squeezed to a Fock state for arbitrary values of the system's parameters. However, this makes detection of Ramsey fringes impossible, because the probability of detecting an atom in the upper or lower electronic state becomes a random quantity almost uniformly distributed over the interval between zero and unity, irrespective of the cavity photon number.

Kozlovskii, A. V. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)], E-mail: kozlovsk@sci.lebedev.ru

2007-04-15

120

Passive scheme with a photon-number-resolving detector for monitoring the untrusted source in a plug-and-play quantum-key-distribution system  

NASA Astrophysics Data System (ADS)

A passive scheme with a beam splitter and a photon-number-resolving (PNR) detector is proposed to verify the photon statistics of an untrusted source in a plug-and-play quantum-key-distribution system by applying a three-intensity decoy-state protocol. The practical issues due to statistical fluctuation and detection noise are analyzed. The simulation results show that the scheme can work efficiently when the total number of optical pulses sent from Alice to Bob is above 108, and the dark count rate of the PNR detector is below 0.5 counts/pulse, which is realizable with current techniques. Furthermore, we propose a practical realization of the PNR detector with a variable optical attenuator combined with a threshold detector.

Xu, Bingjie; Peng, Xiang; Guo, Hong

2010-10-01

121

Spatial Resolution Enhancement in Quantum Imaging beyond the Diffraction Limit Using Entangled Photon-Number State  

Microsoft Academic Search

In this paper we study the resolution of images illuminated by sources composed of $N+1$ photons in which one non-degenerate photon is entangled with $N$ degenerate photons. The $N$ degenerate photons illuminate an object and are collected by an $N$ photon detector. The signal from the $N$ photon detector is measured in coincidence with the non-degenerate photon giving rise to

Jianming Wen; Morton H. Rubin; Yanhua Shih

2008-01-01

122

Joint statistics of photon path length and cloud optical depth: Case studies  

NASA Astrophysics Data System (ADS)

We show the joint statistics of photon path length and cloud optical depth for cloudy sky cases observed at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site between September and December 1997. The photon path lengths are retrieved from moderate resolution oxygen A-band observations taken by a rotating shadow band spectroradiometer (RSS). For high optical depth cloud cases, two different populations in the scattergram of the path length versus cloud optical depth are apparent. One population is a result of single-layer cloud cases that exhibit a small variation of path length enhancement over a large optical depth range, together with a strong correlation between the radiation field and the cloud liquid water path, while the second population is attributed to multiple-layer cloud cases with large variability of enhanced photon path lengths. When the optical depth is less than 5, the population of cases appears to bifurcate as the solar air mass increases, with the lower branch exhibiting pressure-weighted path lengths shorter than the direct beam path lengths at these larger solar zenith angles. Using information from a millimeter-wave cloud radar, together with lidar and balloon-borne sonde data to further analyze these cases demonstrates that this bifurcation is caused by the altitude of the scattering; thin clouds aloft produce the lower branch and low-level aerosols produce the upper branch.

Min, Qilong; Harrison, Lee C.; Clothiaux, Eugene E.

2001-04-01

123

On the spectrum of field quadratures for a finite number of photons  

NASA Astrophysics Data System (ADS)

The spectrum and eigenstates of any field quadrature operator restricted to a finite number N of photons are studied, in terms of the Hermite polynomials. By (naturally) defining approximate eigenstates, which represent highly localized wavefunctions with up to N photons, one can arrive at an appropriate notion of limit for the spectrum of the quadrature as N goes to infinity, in the sense that the limit coincides with the spectrum of the infinite-dimensional quadrature operator. In particular, this notion allows the spectra of truncated phase operators to tend to the complete unit circle, as one would expect. A regular structure for the zeros of the Christoffel-Darboux kernel is also shown.

Pisanty, E.; Nahmad-Achar, E.

2012-10-01

124

Effect of statistical fluctuation in Monte Carlo based photon beam dose calculation on gamma index evaluation  

NASA Astrophysics Data System (ADS)

The ?-index test has been commonly adopted to quantify the degree of agreement between a reference dose distribution and an evaluation dose distribution. Monte Carlo (MC) simulation has been widely used for the radiotherapy dose calculation for both clinical and research purposes. The goal of this work is to investigate both theoretically and experimentally the impact of the MC statistical fluctuation on the ?-index test when the fluctuation exists in the reference, the evaluation, or both dose distributions. To the first order approximation, we theoretically demonstrated in a simplified model that the statistical fluctuation tends to overestimate ?-index values when existing in the reference dose distribution and underestimate ?-index values when existing in the evaluation dose distribution given the original ?-index is relatively large for the statistical fluctuation. Our numerical experiments using realistic clinical photon radiation therapy cases have shown that (1) when performing a ?-index test between an MC reference dose and a non-MC evaluation dose, the average ?-index is overestimated and the gamma passing rate decreases with the increase of the statistical noise level in the reference dose; (2) when performing a ?-index test between a non-MC reference dose and an MC evaluation dose, the average ?-index is underestimated when they are within the clinically relevant range and the gamma passing rate increases with the increase of the statistical noise level in the evaluation dose; (3) when performing a ?-index test between an MC reference dose and an MC evaluation dose, the gamma passing rate is overestimated due to the statistical noise in the evaluation dose and underestimated due to the statistical noise in the reference dose. We conclude that the ?-index test should be used with caution when comparing dose distributions computed with MC simulation.

Jiang Graves, Yan; Jia, Xun; Jiang, Steve B.

2013-03-01

125

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

126

Ultralow-noise readout circuit with an avalanche photodiode: toward a photon-number-resolving detector.  

PubMed

The charge-integration readout circuit was fabricated to achieve an ultralow-noise preamplifier for photoelectrons generated in an avalanche photodiode with linear mode operation at 77 K. To reduce the various kinds of noise, the capacitive transimpedance amplifier was used and consisted of low-capacitance circuit elements that were cooled with liquid nitrogen. As a result, the readout noise is equal to 3.0 electrons averaged for a period of 40 ms. We discuss the requirements for avalanche photodiodes to achieve photon-number-resolving detectors below this noise level. PMID:17304297

Tsujino, Kenji; Akiba, Makoto; Sasaki, Masahide

2007-03-01

127

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

128

How to handle gender and number agreement in statistical language models?  

Microsoft Academic Search

The agreement in gender and number is a critical problem in sta- tistical language modeling. One of the main difficulties in speech recognition of French language is the presence of misrecognized words due to the bad agreement (in gender and number) between words. Statistical language models do not treat this phenomena di- rectly. This paper focuses on how to handle

Caroline Lavecchia; Kamel Smaïli; Jean-Paul Haton

2006-01-01

129

Relation between photon statistics and pumping fluctuations in a dye laser  

SciTech Connect

Measurements of the photon-number fluctuations in a single-mode dye jet laser are compared with solutions of the equations of motion with colored pumping and white spontaneous-emission noise. A search of parameter space for best agreement between theory and experiment shows that the experimental results cannot be well modeled by a theory with white pumping noise, although the correlation time is small, but can be modeled with colored noise. This emphasizes the importance of not treating the pumping fluctuations as delta correlated even for time-independent quantities.

Kim, T.S.; Gage, E.C.; Mandel, L.

1988-08-01

130

Signal-to-noise ratio of quantum imaging using entangled photon-number state  

Microsoft Academic Search

Quantum Imaging involving a source with N+1 photons has been of interest in the recent years. N of these photons are present in the arm where the object is placed and are entangled with 1 photon in the other arm. The image is recorded in coincidence. We present here some ideas on how to generate such photons in the lab

Sai Vinjanampathy; Jeff Adams; Barbara Capron; Claudio Parazzoli; Jonathan Dowling

2010-01-01

131

Statistical theory of multiple scattering of waves applied to three-dimensional layered photonic crystals  

NASA Astrophysics Data System (ADS)

On the basis of the statistical theory of multiple scattering of waves, we offer a numerical approach to calculate coherent transmission and reflection for the three-dimensional (3-D) photonic crystals that consist of partially disordered dielectric spheres. With the proposed scheme, which we call the transfer-matrix (TM) method with quasi-crystalline approximation (QCA), we consider a quasi-regular 3-D assembly of particles as a stack of close-packed monolayers with a short-range ordering. Single-scattering characteristics are determined by Mie theory. Lateral electrodynamic coupling between the particles of a monolayer is treated in the QCA. Multibeam interference between monolayers is described in a manner analogous to the TM technique. We apply the TM-QCA calculation technique to study two revealed effects: (1) short-wavelength attenuation due to particles of finite sizes and (2) nonmonotonic dependence of the pseudogap depth on the particle size, refractive-index contrast, and intermonolayer distances.

Ponyavina, Alina; Kachan, Svetlana; Sil'Vanovich, Nikolaj

2004-10-01

132

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

NASA Astrophysics Data System (ADS)

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.

Šanda, František

2009-10-01

133

Theory of photon-number squeezing in a heterojunction LED by the nonlinear backward pump process  

NASA Astrophysics Data System (ADS)

We present a theoretical framework for sub-Poissonian-photon-state generation based on a microscopic backward-pump (BP) process in a semiconductor heterojunction light-emitting diode (LED). The model, which takes into account the BP and nonradiative recombination processes as well as the dynamical response of the external circuit, is applicable to practical LED's. It is shown that the nonlinear dependence of the BP rate on the carrier number in the active region brings about the photon-number squeezing below the full-shot-noise level, without recourse to a high-impedance constant-current source. We also point out that the bandwidth of the squeezing by the nonlinear BP process is wider than that limited by the recombination lifetime. In addition, we discuss the origin of the nonlinearity of the BP rate based on a microscopic model for the injected carriers in the active region. The nonlinearity is suggested to be due to the rises of the electron temperature and of energetic position of the quasi-Fermi level, with increasing pump current.

Sumitomo, Hiroyuki; Yamanishi, Masamichi; Kadoya, Yutaka

2002-04-01

134

Sub-Poissonian photon statistics and higher-order squeezing behavior of Bernoulli states in the linear amplifier  

NASA Astrophysics Data System (ADS)

A parametric study was performed of the sub-Poissonian photon statistics and higher-order squeezing characteristics of Bernoulli states undergoing a linear amplification process. The necessary and sufficient conditions on the amplifier gain under which the output light exhibits sub-Poissonian photon statistics or squeezing were compared with exact numerical results, and good agreement was obtained. On the other hand, it was shown that Bernoulli states exhibit higher-order squeezing for some parameter ranges. The degree of higher-order squeezing decreases, and its duration becomes shorter, as the phase of the Bernoulli state increases.

Garcia-Fernandez, P.; Bermejo, F. J.

1987-10-01

135

Large-photon-number extraction from individual atoms trapped in an optical lattice  

SciTech Connect

The atom-by-atom characterization of quantum gases requires the development of novel measurement techniques. One particularly promising new technique demonstrated in recent experiments uses strong fluorescent laser scattering from neutral atoms confined in a short-period optical lattice to measure the positions of individual atoms in the sample. A crucial condition for the measurements is that atomic hopping between lattice sites must be strongly suppressed despite substantial photon recoil heating. This paper models three-dimensional polarization gradient cooling of atoms trapped within a far-detuned optical lattice. The atomic dynamics are simulated using a hybrid Monte Carlo and master-equation analysis in order to predict the frequency of processes which give rise to degradation or loss of the fluorescent signal during measurements. It is shown, consistently with the experimental results, that there exists a wide parameter range in which the lifetime of strongly fluorescing isolated lattice-trapped atoms is limited by background gas collisions rather than radiative processes. In these cases the total number of scattered photons can be as large as 10{sup 8} per atom. The performance of the technique is related to relevant experimental parameters.

Shotter, M. D. [Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom) and National Institute of Standards and Technology, 100 Bureau Drive, Stop 8423, Gaithersburg, Maryland 20899-8423 (United States)

2011-03-15

136

Atmospheric particle number size distribution in central Europe: Statistical relations to air masses and meteorology  

Microsoft Academic Search

Atmospheric particle number size distributions determined over 1.5 years at a central European site were statistically analyzed in terms of their relation to time of day, season, meteorology, and synoptic-scale air masses. All size distributions were decomposed into lognormal particle modes corresponding to the accumulation, Aitken, aged nucleation, and nucleation modes. The concentration of nucleation mode particles (30 nm) lacked

Wolfram Birmili; Alfred Wiedensohler; Jost Heintzenberg; Katrin Lehmann

2001-01-01

137

Temperature-Independent Casimir-Polder Forces Despite Large Thermal Photon Numbers  

SciTech Connect

We demonstrate that Casimir-Polder potentials can be entirely independent of temperature even when allowing for the relevant thermal photon numbers to become large. This statement holds for potentials that are due to low-energy transitions of a molecule placed near a plane metal surface whose plasma frequency is much larger than any atomic resonance frequencies. For a molecule in an energy eigenstate, the temperature independence is a consequence of strong cancellations between nonresonant potential components and those due to evanescent waves. For a molecule with a single dominant transition in a thermal state, upward and downward transitions combine to form a temperature-independent potential. The results are contrasted with the case of an atom whose potential exhibits a regime of linear temperature dependence. Contact with the Casimir force between a weakly dielectric and a metallic plate is made.

Ellingsen, Simen A. [Department of Energy and Process Engineering, Norwegian University of Science and Technology, N-7491 Trondheim (Norway); Buhmann, Stefan Yoshi; Scheel, Stefan [Quantum Optics and Laser Science, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom)

2010-06-04

138

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

139

Photon statistics and squeezing of a free-electron laser for an initial Bose-Einstein distribution and for an initial nearly pure state  

Microsoft Academic Search

We investigate numerically the photon statistics and squeezing properties of the free-electron laser. In one model we assume the initial distribution of photons to be thermal (Bose-Einstein distribution). Our results for this model indicate no photon antibunching. We obtain similar results for another model, where we have started from an initial distribution which is nearly a pure state (the ..cap

Suranjana Rai; Jagdish Rai; S. Chopra

1987-01-01

140

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

141

Dynamics and Nonclassical Photon Statistics in the Interaction of Two-Level Spin Systems with a Two-Mode Cavity Field:. a Generalized Jaynes-Cummings Model  

NASA Astrophysics Data System (ADS)

The interaction of a two-level XY n-spin system with a two-mode cavity field is investigated through a generalized Jaynes-Cummings model in the rotating wave approximation. The spontaneous decay of a spin level was treated by considering the interaction of the two-level spin system with the modes of the universe in the vacuum state. The different cases of interest, characterized in terms of a detuning parameter for each mode, which emerge from the nonvanishing of certain commutation relations between interaction picture Hamiltonians associated with each mode, were analytically implemented and numerically discussed for various values of the initial mean photon number and spin-photon coupling constants. Photon distribution, time evolution of the spin population inversion, as well as the statistical properties of the field leading to the possible production of nonclassical states, such as antibunched light and violations of the Cauchy-Schwartz inequality are examined for an excited initial state. It was assumed that the two modes are initially in coherent states and have the same photon distribution. The case of zero detuning of both modes was treated in terms of a linearization of the expansion of the time evolution operator, while in other three cases, the computations were conducted via second- and third-order Dyson perturbation expansion of the time evolution operator matrix elements for the excited and ground states respectively.

Grinberg, Horacio

142

Statistical Evoked Potential Detection with Number of Degrees of Freedom Estimated from EEG Autocorrelation Function  

Microsoft Academic Search

\\u000a Statistical Objective Response Detection (ORD) Techniques applied to Evoked Potentials usually depend on the effective Number\\u000a of Degrees of Freedom (NDOF) of spontaneous EEG. This work proposes a method for estimating the NDOF of the EPD (Evoked Potential Detector) probability distribution under the null hypothesis of no response, based on the EEG autocorrelation function (ACF). Its\\u000a performance was assessed by

Maurício Cagy; A. Fernando C. Infantosi; A. M. F. L. Miranda Sá; David M. Simpson

143

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 (>10dB) 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 -2.6dB. PMID:24150352

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

2013-10-21

144

Time-Evolution of Photon-Number Distribution and Density Operator of Squeezed Thermal State in the Thermal Environment  

NASA Astrophysics Data System (ADS)

By virtue of the thermal entangled state representation, we analytically study time-dependent evolution of photon-number distribution and density operator of squeezed thermal state (STS) in the thermal environment. It is found that the initial density operator of STS still keeps squeezing and thermal within the thermal environment. At long times, such a state decays to thermal, a Gaussian classical state, as a result of decoherence. Moreover, the oscillations of photon-number distribution slowly disappear with increasing t, but the change of oscillations is completely different from that of STS in amplitude dissipative channel.

Xu, Ye-Jun; Meng, Xiang-Guo

2013-11-01

145

Which is the most suitable number of photon beam portals in coplanar radiation therapy?  

SciTech Connect

Computer-controlled milling machines for compensator manufacture, dynamic multileaf collimators, and narrow scanned electron or bremsstrahlung photon beams have opened up new possibilities to shape nonuniform fluence profiles and have thus, paved the road for truly three dimensional (3D) dose delivery. The present paper investigates the number of beam portals required to optimize coplanar radiation therapy using uniform and nonuniform dose delivery. Nonuniform dose delivery allows a considerable improvement in the treatment outcome compared to uniform dose delivery. The results also show a close relationship between the dose distribution parameters and the probability of achieving complication-free tumor control. To achieve optimal expectation value of the treatment outcome, within an accuracy of a few percent as measured by the probability of achieving complication-free tumor control, it is generally sufficient to use three nonuniform beam portals. A very large number of coplanar beams may only raise the probability of achieving complication-free tumor control by 1 to 2%. However, good treatment outcome with three beam portals requires that the directions of incidence of the coplanar nonuniform beams are optimally selected. If, on the other hand, the treatment is performed using uniform beams, it is not possible, even with an infinite number of fields, to obtain as high a level of complication-free tumor control as with a few nonuniform beams. From an optimization point of view, it is sufficient to reach a relative standard deviation of the mean dose to the target volume of around 3%. Improved dose homogeneity beyond this level will, in general, not significantly improve the complication-free tumor control. 20 refs., 5 figs., 2 tabs.

Soederstroem, S.; Brahme, A. [Univ. of Stockholm (Sweden)

1995-08-30

146

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

147

Single molecule analysis of DNA synthesis using non-classical photon statistics  

Microsoft Academic Search

The fidelity of DNA replication is important for maintaining cell function and survival. DNA polymerases play a crucial role in the processes of replication and repair. Using non-classical photon emission from fluorescently labeled incorporated nucleotides, we have developed a procedure for monitoring the action of polymerases on single molecules of DNA. We previously showed fluorescence photon antibunching spectroscopy allows for

S. Fore; Y. Yeh; T. Huser; R. Balhorn; M. Cosman; T. Laurence

2004-01-01

148

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

149

The Person-Number Systems of Sweden, Norway, Denmark, and Israel. Vital and Health Statistics. Data Evaluation and Methods Research, Series 2, Number 84.  

ERIC Educational Resources Information Center

|The booklet presents a report on the operation and use of person numbering (PN) systems for vital and health statistics in Israel and Scandinavia. A PN system involves assigning a different number to each individual within a given society and using that number for commercial, governmental, and military identification. The purpose of the report is…

National Center for Health Statistics (DHEW/PHS), Hyattsville, MD.

150

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

NASA Astrophysics Data System (ADS)

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.

1992-08-01

151

A statistical model estimating the number of African-American physicians in the United States.  

PubMed Central

Using mark-recaptured methodology and network sampling procedures, a statistical model was developed to estimate the number of African-American physicians in the United States. A sample (stratified by geographic region, medical specialty and an age surrogate) was selected from the National Medical Association's Masterfile of Black Physicians (NMAMBP). Respondents were asked to list the names of five black physicians who resided or practiced in their immediate geographic area. Data also were collected about citizenry as well as other demographic and professional information. The NMAMBP was used mathematically as a "marked" group that could then be "recaptured," allowing mark-recapture methodology to be used as the nucleus of the statistical estimation procedure. The results revealed that in 1991, the total number of US African-American physicians (black US citizens) was estimated to be 16,282 with a conservative standard error of 764 and an approximate 95% confidence interval, yielding a range of 14,754 to 17,810 physicians. This estimate is from 17% to about 32% lower than the 21,538 black doctors reported by the 1990 Bureau of the Census and has important implications for attempts to reform the health-care system and policies designed to produce more African-American physicians.

King, G.; Bendel, R.

1995-01-01

152

Mapping Tumor-Suppressor Genes with Multipoint Statistics from Copy-Number-Variation Data  

PubMed Central

Array-based comparative genomic hybridization (arrayCGH) is a microarray-based comparative genomic hybridization technique that has been used to compare tumor genomes with normal genomes, thus providing rapid genomic assays of tumor genomes in terms of copy-number variations of those chromosomal segments that have been gained or lost. When properly interpreted, these assays are likely to shed important light on genes and mechanisms involved in the initiation and progression of cancer. Specifically, chromosomal segments, deleted in one or both copies of the diploid genomes of a group of patients with cancer, point to locations of tumor-suppressor genes (TSGs) implicated in the cancer. In this study, we focused on automatic methods for reliable detection of such genes and their locations, and we devised an efficient statistical algorithm to map TSGs, using a novel multipoint statistical score function. The proposed algorithm estimates the location of TSGs by analyzing segmental deletions (hemi- or homozygous) in the genomes of patients with cancer and the spatial relation of the deleted segments to any specific genomic interval. The algorithm assigns, to an interval of consecutive probes, a multipoint score that parsimoniously captures the underlying biology. It also computes a P value for every putative TSG by using concepts from the theory of scan statistics. Furthermore, it can identify smaller sets of predictive probes that can be used as biomarkers for diagnosis and therapeutics. We validated our method using different simulated artificial data sets and one real data set, and we report encouraging results. We discuss how, with suitable modifications to the underlying statistical model, this algorithm can be applied generally to a wider class of problems (e.g., detection of oncogenes).

Ionita, Iuliana; Daruwala, Raoul-Sam; Mishra, Bud

2006-01-01

153

Vital and Health Statistics, Series 15, Number 3. Summary Statistics from the National Survey of Early Childhood Health, 2000.  

National Technical Information Service (NTIS)

This report presents statistics from the 2000 National Survey of Early Childhood Health (NSECH) on selected measures for children 4-35 months of age. The topics covered include usual source of care, parental perceptions of pediatric care, interactions wit...

2002-01-01

154

Photon statistics and squeezing of a free-electron laser for an initial Bose-Einstein distribution and for an initial nearly pure state  

SciTech Connect

We investigate numerically the photon statistics and squeezing properties of the free-electron laser. In one model we assume the initial distribution of photons to be thermal (Bose-Einstein distribution). Our results for this model indicate no photon antibunching. We obtain similar results for another model, where we have started from an initial distribution which is nearly a pure state (the ..cap alpha..-..beta.. model). However, both these models exhibit squeezing.

Rai, S.; Rai, J.; Chopra, S.

1987-04-01

155

Discovery and statistical genotyping of copy-number variation from whole-exome sequencing depth.  

PubMed

Sequencing of gene-coding regions (the exome) is increasingly used for studying human disease, for which copy-number variants (CNVs) are a critical genetic component. However, detecting copy number from exome sequencing is challenging because of the noncontiguous nature of the captured exons. This is compounded by the complex relationship between read depth and copy number; this results from biases in targeted genomic hybridization, sequence factors such as GC content, and batching of samples during collection and sequencing. We present a statistical tool (exome hidden Markov model [XHMM]) that uses principal-component analysis (PCA) to normalize exome read depth and a hidden Markov model (HMM) to discover exon-resolution CNV and genotype variation across samples. We evaluate performance on 90 schizophrenia trios and 1,017 case-control samples. XHMM detects a median of two rare (<1%) CNVs per individual (one deletion and one duplication) and has 79% sensitivity to similarly rare CNVs overlapping three or more exons discovered with microarrays. With sensitivity similar to state-of-the-art methods, XHMM achieves higher specificity by assigning quality metrics to the CNV calls to filter out bad ones, as well as to statistically genotype the discovered CNV in all individuals, yielding a trio call set with Mendelian-inheritance properties highly consistent with expectation. We also show that XHMM breakpoint quality scores enable researchers to explicitly search for novel classes of structural variation. For example, we apply XHMM to extract those CNVs that are highly likely to disrupt (delete or duplicate) only a portion of a gene. PMID:23040492

Fromer, Menachem; Moran, Jennifer L; Chambert, Kimberly; Banks, Eric; Bergen, Sarah E; Ruderfer, Douglas M; Handsaker, Robert E; McCarroll, Steven A; O'Donovan, Michael C; Owen, Michael J; Kirov, George; Sullivan, Patrick F; Hultman, Christina M; Sklar, Pamela; Purcell, Shaun M

2012-10-01

156

Small Business Management Series Number 22. Practical Business Use of Government Statistics.  

National Technical Information Service (NTIS)

The booklet illustrates some practical uses of Government statistics, provides a general overview of what can be done with Government statistics, and describes important sources and references. The topics discussed are: The Statistical Abstract of the Uni...

T. T. Semon

1975-01-01

157

Statistics of Income (SOI) Bulletin: Summer 2008. Volume 28, Number 1.  

National Technical Information Service (NTIS)

The Statistics of Income (SOI) Bulletin is issued quarterly, in February, May, August, and November, by the Statistics of Income Division of the Internal Revenue Service. The report provides the earliest published annual financial statistics obtained from...

2008-01-01

158

Statistics of Income (SOI) Bulletin: Volume 30, Number 1, Fall 2010.  

National Technical Information Service (NTIS)

The Statistics of Income (SOI) Bulletin is issued quarterly by the Statistics of Income Division of the Internal Revenue Service. The report provides the earliest published annual fi nancial statistics obtained from the various types of tax and informatio...

2010-01-01

159

Statistical methods for designing and assessing the effectiveness of community-based interventions with small numbers.  

PubMed

Community-based interventions are, by their nature, tailored to the particular needs of the members and stakeholders of the community. In the area of safety promotion, the multifaceted aspects of violence and unintentional injuries necessitate complex intertwining of strategies and approaches. The evaluation of the effectiveness of any 'intervention' programme, either as a whole or of its discrete components, is thus challenging. In addition, standard experimental research designs involving controlled comparisons and the use of randomisation are often not practical. The evaluation is complicated further when the numbers of events in the community that constitute outcomes to be measured, before and after the interventions, are small. This manuscript reviews some of the statistical considerations that impact the evaluation of the effectiveness of such intervention approaches, and proposes a meta-regression methodology to address this complex issue. The application of the proposed methodology to the 'Safe Community' Model is provided as an example. PMID:22800444

Bangdiwala, Shrikant I; Villaveces, Andrés; Garrettson, Mariana; Ringwalt, Chris

2012-07-17

160

The effect of beam energy and number of fields on photon-based IMRT for deep-seated targets  

Microsoft Academic Search

Purpose: To examine the influence of energy and number of beams on nontarget dose when using intensity-modulated radiation therapy (IMRT) to treat deep-seated targets.Methods and Materials: Ten patients with prostate cancer (36–226 cc) treated locally to 75.6 Gy were studied. IMRT plans were created for 6-, 10-, and 18-MV photons using 4, 6, 9, and 11 coplanar nonopposed fields. Plans,

Andrea Pirzkall; Mark P Carol; Barby Pickett; Ping Xia; Mack Roach; Lynn J Verhey

2002-01-01

161

Coherence holography and photon-correlation holography: marriage between holography and statistical optics  

NASA Astrophysics Data System (ADS)

We review two techniques of unconventional holography, coherence holography and photon-correlation holography, which we recently proposed and experimentally demonstrated. We will emphasize the importance of noticing mathematical analogies in optics and physical phenomena, which give insights into the methodology for developing new techniques.

Takeda, Mitsuo; Wang, Wei; Naik, Dinesh N.

2011-09-01

162

SPECIAL ISSUE DEVOTED TO MULTIPLE RADIATION SCATTERING IN RANDOM MEDIA: Time-domain diffuse optical tomography using analytic statistical characteristics of photon trajectories  

NASA Astrophysics Data System (ADS)

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.

Konovalov, Aleksandr B.; Vlasov, V. V.; Kalintsev, A. G.; Kravtsenyuk, Olga V.; Lyubimov, Vladimir V.

2006-11-01

163

Quantum state engineering with entangled squeezed states and photon number detector  

Microsoft Academic Search

The photon subtraction operation is an effective method to enhance an entanglement of the two-mode squeezed vacuum state. We show that it can be well approximated to the two-mode squeezed state with an enhanced squeezing although it is basically a mixed and non-Gaussian state. Such property can be directly observed by the current technology. We also study the continuous variable

Akira Kitagawa; Katsuji Yamamoto; Koji Nagata; Masahiro Takeoka; Masahide Sasaki

2005-01-01

164

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

165

Effect of flow velocity on the photon statistics of a cw dye laser  

SciTech Connect

The effect of changing the velocity of dye flow on the behavior of a cw dye laser in investigated by photon counting measurements. The results strongly suggest that changing the velocity over the range 10--13 m/sec merely changes the pump parameter, but leaves the other laser characteristics essentially unaltered. The average light intensity is found to be a linear function of flow velocity.

Short, R.; Roy, R.; Mandel, L.

1980-12-01

166

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

167

Photon-photon collisions  

SciTech Connect

Studies of photon-photon collisions are reviewed with particular emphasis on new results reported to this conference. These include results on light meson spectroscopy and deep inelastic e..gamma.. scattering. Considerable work has now been accumulated on resonance production by ..gamma gamma.. collisions. Preliminary high statistics studies of the photon structure function F/sub 2//sup ..gamma../(x,Q/sup 2/) are given and comments are made on the problems that remain to be solved.

Burke, D.L.

1982-10-01

168

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.

169

Correlation between the number of quantum-statistical modes of the exciting field and the number of lines in the resonance fluorescence spectrum  

SciTech Connect

The quasi-energy wave functions of a two-level atom in an electromagnetic field, the state of which represents a superposition of coherent states, were found. The fluorescence spectrum of an atom excited by such a field was investigated. It was shown that a spectral fluorescence mode corresponds to each mode of the quantum-statistical distribution of the field incident on the atom. This means that the number of statistical modes of the incident field may be recorded as the number of data bits of the information carried by the light pulse. (laser applications and other topics in quantum electronics)

Kryzhanovskii, Boris V; Sokolov, G B [Institute of Optical Neural Technologies, Russian Academy of Sciences, Moscow (Russian Federation)

2000-03-31

170

Vital and Health Statistics. Advance Data from Vital and Health Statistics: Numbers 51-60. Series 16: Compilations of Advance Data from Vital and Health Statistics, No. 6.  

National Technical Information Service (NTIS)

Data in the report from health and demographic surveys present statistics by age and other variables on ambulatory medical care; changes in cigarette smoking practices; fats, cholesterol, and sodium intake in the diet; reproductive impairments among curre...

1991-01-01

171

Effects of Lewis number on conditional fluid velocity statistics in low Damköhler number turbulent premixed combustion: A direct numerical simulation analysis  

NASA Astrophysics Data System (ADS)

The effects of global Lewis number Le on the statistics of fluid velocity components conditional in unburned reactants and fully burned products in the context of Reynolds Averaged Navier Stokes simulations have been analysed using a Direct Numerical Simulations (DNS) database of statistically planar turbulent premixed flames with a low Damköhler number and Lewis number ranging from 0.34 to 1.2. The conditional velocity statistics extracted from DNS data have been analysed with respect to the well-known Bray-Moss-Libby (BML) expressions which were derived based on bi-modal probability density function of reaction progress variable for high Damköhler number flames. It has been shown that the Lewis number substantially affects the mean velocity and the velocity fluctuation correlation conditional in products, with the effect being particularly pronounced for low Le. As far as the mean velocity and the velocity fluctuation correlation conditional in reactants are concerned, the BML expressions agree reasonably well with the DNS data reported in the present work. Based on a priori analysis of present and previously reported DNS data, the BML expressions have been empirically modified here in order to account for Lewis number effects, and the non-bimodal distribution of reaction progress variable. Moreover, it has been demonstrated for the first time that surface averaged velocity components and Reynolds stresses conditional in unburned reactants can be modelled without invoking expressions involving the Lewis number, as these surface averaged conditional quantities remain approximately equal to their conditionally averaged counterparts in the unburned mixture.

Chakraborty, Nilanjan; Lipatnikov, Andrei N.

2013-04-01

172

Statistical characterization of multi-conductor cables using large numbers of measurements.  

SciTech Connect

Understanding and characterizing the electrical properties of multi-conductor shielded and unshielded cables is an important endeavor for many diverse applications, including airlines, land based communications, nuclear weapons, and any piece of hardware containing multi-conductor cabling. Determining the per unit length capacitance and inductance based on the geometry of the conductors, number of conductors, and characteristics of the shield can prove quite difficult. Relating the inductance and capacitance to shielding effectiveness can be even more difficult. An exceedingly large number of measurements were taken to characterize eight multi-conductor cables, of which four were 3-conductor cables and four were 18-conductor cables. Each set of four cables contained a shielded cable and an unshielded cable with the inner conductors twisted together and a shielded cable and an unshielded cable with the inner conductors not twisted together (or straight). Male LJT connectors were attached on either end of the cable and each cable had a finished length of 22.5 inches. The measurements performed were self and mutual inductance, self and mutual capacitance, and effective height. For the 18 conductor case there ended up being an 18 by 18 element matrix for inductance (with the self inductance terms lying on the diagonal) and an 18 by 18 matrix for capacitance. The effective height of each cable was measured over a frequency range from 220 MHz to 18 GHz in a Mode-Stirred Chamber. The effective height of each conductor of each cable was measured individually and all shorted together, producing 19 frequency responses for each 18 conductor cable. Shielding effectiveness was calculated using the effective heights from the shielded and unshielded cables. The results of these measurements and the statistical analysis of the data will be presented. There will also be a brief presentation of comparison with numerical models.

Higgins, Matthew B.

2005-01-01

173

Statistical tests for a correlation between decadal variation in June precipitation in China and sunspot number  

NASA Astrophysics Data System (ADS)

Six different statistical methods (i.e., correlation, difference, prominent period, variance contribution, scale-averaged spectrum, and cross spectrum) are used to test for regional differences in the relationship between the 11 year sunspot cycle and June precipitation in China during the 20th century. In the Huaihe River basin (HRB) of central China, located at the marginal region of the East Asian summer monsoon (EASM), there exists a reliable positive-correlation relationship between the 11 year sunspot cycle and June precipitation; whereas, possible negative and very weak positive correlations in the south of the middle-lower Yangtze River Region and the HeTao Basin (HTB), located in the interior of the EASM and the westerlies, respectively. The reasons for these regional differences are investigated, revealing that the marginal region of EASM may be more sensitive to solar forcing than is its interior, which results in the HRB becoming the most susceptible (strongest correlation) region. That is to say, in June during the high sunspot number (SSN) years, the influence of the EASM is significantly greater and more to the north than that in June during the low SSN years, causing the HRB to be mainly influenced by the EASM (westerlies) in June during the high (low) SSN years. The northward expansion of the June EASM probably resulted from enhancement of the low-level southwesterly monsoon flow over the northern tropical Indian Ocean, combined with an expansion of the western Pacific subtropical high at times of high SSN.

Wang, Jing-Song; Zhao, Liang

2012-12-01

174

Photon statistics in blinking fluorescence of single PPV-PPyV molecule  

NASA Astrophysics Data System (ADS)

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 won, 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.

Fedyanin, V. V.; Osad'Ko, I. S.

2011-09-01

175

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

176

Effect on number albedo values for 662 keV photons from radiation shielding materials stratified with lead  

NASA Astrophysics Data System (ADS)

Albedo measurements for backscattered gamma rays from semi-infinite scatterers have suitable applications in the design of gamma ray shields particularly in nuclear reactor and accelerator shields and in many other nuclear installations. The insertion of lead slabs into stratified combination with other shielding materials has been found to increase the shielding property appreciably. The stratified slabs of alternating heterogeneous layers have been found in this investigation to have a virtual homogeneous property with a definite effective atomic number. The purpose of the present investigation is to find out the extent to which the shielding property increases in binary configuration with lead and to investigate into the dependence of the saturation thickness of the shielding media on the effective atomic number of each configuration. The indigeneously designed Uniform Sensitivity Photon Counter used in this investigation has an edge over all previous methods of experimental measurements that it is independent of response correction. The number albedo values as well as angular distribution of backscattered photons for iron, aluminium and concrete stratified with lead slabs at 662 keV energy have been reported here.

Bhattacharjee, A.; Sinha, A. K.

1988-07-01

177

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

178

Case Study Applications of Statistics in Institutional Research. Resources in Institutional Research, Number Ten.  

ERIC Educational Resources Information Center

|This monograph covers the theory, application, and interpretation of both descriptive and inferential statistical techniques in institutional research. Each chapter opens with a hypothetical case study, which is used to illustrate the application of one or more statistical procedures to typical research questions. Chapter 2 covers the comparison…

Coughlin, Mary Ann; Pagano, Marian

179

The choice of the number of bins for the M statistic  

Microsoft Academic Search

Methods to monitor spatial patterns of disease in populations are of interest in public health practice. The M statistic uses interpoint distances between cases to detect abnormalities in the spatial patterns of diseases. This statistic compares the observed distribution of interpoint distances with that which is expected when no unusual spatial patterns exist. We show the relationship of M to

Laura Forsberg White; Marco Bonetti; Marcello Pagano

2009-01-01

180

Statistical properties of a two-photon cavity mode in the presence of degenerate parametric amplifier  

SciTech Connect

A Hamiltonian model that includes two-photon interaction with a two-level atom and a degenerate parametric amplifier is considered. By invoking a canonical transformation an exact solution of the wave function in the Schroedinger picture is obtained. The result presented in this context is employed to discuss the purity, the entropy squeezing, and the variance squeezing, in addition to the normal squeezing. It has been shown that the existence of the second harmonic generation leads to reduction in the squeezing amount for all quadrature variances and we found that as the value of the coupling parameter {lambda}{sub 2} increases the squeezing phenomenon gets more apparent. Further we have also considered the Q-function as an example of the quasi-probability distribution.

Abdalla, M. Sebawe [Mathematics Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia)], E-mail: m.sebaweh@physics.org; Khalil, E.M. [Mathematics Department, Faculty of Science, Al-Azhar University, Nasr City 11884, Cairo (Egypt)], E-mail: eiedkhalil@yahoo.com; Obada, A.S.-F. [Mathematics Department, Faculty of Science, Al-Azhar University, Nasr City 11884, Cairo (Egypt)], E-mail: asobada@yahoo.com

2007-11-15

181

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

182

Journal of Transportation and Statistics, Volume 2, Number 2, December 1999.  

National Technical Information Service (NTIS)

Contents: Letter from the Director of the Bureau of Transportation Statistics; Papers in This Issue - The Structure of Public Transit Costs in the Presence of Multiple Serial Correlation; On the Measurement and Valuation of Travel Time Variability Due to ...

1999-01-01

183

The number of photon counting measurements, the visibility and the intensity  

Microsoft Academic Search

Summary  We calculate, under certain ideal conditions, the number of counting measurements,n\\u000a c, necessary to guarantee a measurement of the visibility of an interference pattern within a specified precision ?, with a\\u000a specified probabilityP\\u000a 0, in a single experimental run. Also we find that if the light intensity for an ideal laser is decreased (or increased), then\\u000a the expected number of

V. Buonomano

1985-01-01

184

Advance Data from Vital and Health Statistics: Numbers 241-250.  

National Technical Information Service (NTIS)

Data in the report from health and demographic surveys present statistics by age and other variables on health of the foreign-born population; firearm and motor vehicle injury mortality; AIDS knowledge and attitudes; nursing homes and board and care homes...

1995-01-01

185

An exact statistical method for comparing topographic maps, with any number of subjects and electrodes  

Microsoft Academic Search

Summary Statistical methods for testing differences between neural images (e.g., PET, MRI or EEG maps) are problematic because they require (1) an untenable assumption of data sphericity and (2) a high subject to electrode ratio. We propose and demonstrate an exact and distribution-free method of significance testing which avoids the sphericity assumption and may be computed for any combination of

Walt Karniski; R. Clifford Blair; Arthur David Snider

1994-01-01

186

Who Pays for the Medical Care of People with Disabilities? Disability Statistics Abstract, Number 13.  

ERIC Educational Resources Information Center

|This statistical abstract presents data on the sources of payment for medical care for people with disabilities in different age groups. All estimates come from the National Medical Expenditures Survey, a nationally representative survey of the civilian non-institutionalized population of the U.S. conducted in 1987. Six categories of payment…

Trupin, Laura; Rice, Dorothy P.; Max, Wendy

187

Database and Online Statistics for 1979: Number of Databases Shows Dramatic Increase.  

ERIC Educational Resources Information Center

|Provides statistical summaries of database development and growth for 1979, based on the "Database of Databases" file at the University of Illinois Information Retrieval Research Laboratory. Bibliographic, bibliographic-related, and natural language databases are analyzed in four subject categories: scientific/technical, humanities, mixed, and…

Williams, Martha E.

1980-01-01

188

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

189

Superradiance, Berry phase, photon phase diffusion, and number squeezed state in the U(1) Dicke (Tavis-Cummings) model  

SciTech Connect

Recently, strong-coupling regimes of superconducting qubits or quantum dots inside a microwave circuit cavity and BEC atoms inside an optical cavity were achieved experimentally. The strong-coupling regimes in these systems were described by the Dicke model. Here, we solve the Dicke model by a 1/N expansion. In the normal state, we find a {radical}(N) behavior of the collective Rabi splitting. In the superradiant phase, we identify an important Berry phase term that has dramatic effects on both the ground state and the excitation spectra of the strongly interacting system. The single photon excitation spectrum has a low-energy quantum phase diffusion mode in imaginary time with a large spectral weight and also a high-energy optical mode with a low spectral weight. The photons are in a number squeezed state that may have wide applications in high sensitive measurements and quantum-information processing. Comparisons with exact diagonalization studies are made. Possible experimental schemes to realize the superradiant phase are briefly discussed.

Ye Jinwu [Beijing Key Laboratory for Terahertz Spectroscopy and Imaging, Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Department of Physics, Capital Normal University, Beijing 100048 (China); Department of Physics and Astronomy, Mississippi State University, Mississippi State, Mississippi 39762 (United States); Zhang Cunlin [Beijing Key Laboratory for Terahertz Spectroscopy and Imaging, Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Department of Physics, Capital Normal University, Beijing 100048 (China)

2011-08-15

190

Problems of Channel Correlation and Statistical Bias in Photon-Correlation Spectroscopy  

Microsoft Academic Search

Correlation between channels of the normalized photocount-rate correlation function g(2)(?) becomes significant at high count rates and leads to a number of data-analysis problems. We derive an expression for channel correlation that is valid for a detector area of arbitrary extent and compare the theoretical predictions with measured values. A data-analysis procedure is demonstrated that employs the theoretical expression for

Richard C. Haskell; Gary L. Pisciotta

1985-01-01

191

Intended and Unintended Births in the United States: 1982-2010. National Health Statistics Reports Number 55.  

National Technical Information Service (NTIS)

This report provides some basic statistics on the extent to which women in the United States are able, or unable, to have the number of births they want, when they want them. In this report, this measure is called the standard measure of unintended pregna...

J. Jones J. C. Abma W. D. Mosher

2012-01-01

192

Locally Determining the Number of Neighbors in the k-Nearest Neighbor Rule Based on Statistical Confidence  

Microsoft Academic Search

The k-nearest neighbor rule is one of the most attractive pattern classification algorithms. In practice, the value of k is usually determined by the cross-validation method. In this work, we propose a new method that locally determines the number of nearest neighbors based on the concept of statistical confidence. We define the confidence associated with decisions that are made by

Jigang Wang; Predrag Neskovic; Leon N. Cooper

2005-01-01

193

Statistical Tests of the Apple IIe Random Number Generator Yield Suggestions from Generator Seeding.  

ERIC Educational Resources Information Center

|Discusses flaws in the Apple IIe Applesoft random number generator, RND, and reports results of frequency and serial correlation tests of the generator. Suggestions of seeds that yield sequences of numbers which pass fundamental screening tests for randomness are presented. (Author/LRW)|

Gleason, John M.

1988-01-01

194

Phat photons and phat lasers  

NASA Astrophysics Data System (ADS)

The initial theoretical finding that eventually led to laser development was Einstein's prediction, based upon statistical considerations, that the energy of quanta of light be given by Planck's constant times the frequency of the light. A new theoretical development based upon Weyl's gauge field theory predicts that photon energies are quantized with the energy given by N2h?. Such quantization of photon energy changes the character of the photon from the Einstein photon that does not have a quantum number. Photon energy that includes a quantum number means that for a given energy the frequency may have more than one value. Conversely, photons of a given frequency may be found that have more energy than the Einstein photon. Further, the phat photons, all at a given frequency will have energy proportional to the number of phat photons and N2. For these phat photons the electric field strength, which causes breakdown in optical fibers or air, depends linearly on N. Thus, more energy may be transmitted using phat photons of higher quantum numbers than increasing the number of photons of lesser quantum numbers while still keeping the electric field below the breakdown level. Further, while the stimulated and spontaneous emission probabilities are proportional to 1/N2 the Rayleigh scattering cross section diminishes by 1/N8. This reduction in the scattering cross section means that a laser emitting phat photons with N<1 will lose less energy traveling through the Earth's atmosphere than lasers using N=1. This reduction in energy losses through the atmosphere means increased efficiency for Earth based beamed applications. This presentation discusses the fundamental theory, emission probabilities, and cross section calculations.

Williams, Pharis E.

2013-10-01

195

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

196

Getting the numbers right: statistical mischief and racial profiling in heart failure research.  

PubMed

The claim that blacks die from heart failure at a rate twice that of whites is informing efforts to develop and market the drug BiDil, which is currently undergoing clinical trials to be approved by the FDA as the first drug ever specified to treat African Americans--and only African Americans--for heart failure. The drug and its companion statistic have since come to play prominent roles in debates about so-called "racial profiling" in medicine and the legitimacy of using social categories of race in biomedical research. Nonetheless, this statistic is wrong. The most current data available place the black:white mortality ratio for heart failure at approximately 1.1:1. The article tells the story of attempts to get to the source of the supposed 2:1 mortality ratio and explores some of the implications of the acceptance of these erroneous data, both for the allocation of resources to combat disease and for our broader understanding of the nature and meaning of race. PMID:14593217

Kahn, Jonathan

2003-01-01

197

First measurement of scintillation photon arrival statistics using a high-granularity solid-state photosensor enabling time-stamping of up to 20,480 single photons  

Microsoft Academic Search

We propose a novel experimental method using a single-photon avalanche diode and time-to-digital convertor (SPAD-TDC) array that, for the first time, enables simultaneous measurement of the spatial and time dependence of the arrival of optical photons in a scintillation pulse with high resolution (tunable between 55 and 100 ps in time, 50 µm in space). By registering all available timing

J. R. Meijlink; C. Veerappan; S. Seifert; D. Stoppa; R. K. Henderson; E. Charbon; D. R. Schaart

2011-01-01

198

Statistical lower bounds on protein copy number from fluorescence expression images  

Microsoft Academic Search

Motivation: Fluorescence imaging has become commonplace for quantitatively measuring mRNA or protein expression in cells and tissues. However, such expression data is usually relative—absolute concentrations or molecular copy numbers are typically not known. While this is satisfactory for many applications, for certain kinds of quantitative network modeling and analysis of expression noise, absolute measures of expression are necessary. Results: We

Lee Zamparo; Theodore J. Perkins

2009-01-01

199

The Political Economy of Numbers: On the Application of Benford's Law to International Macroeconomic Statistics  

Microsoft Academic Search

In this paper we present a technique for assessing data quality based on conformity with Benford's Law, which states that the first digits of numbers generated from natural phenomena do not occur with equal frequency. If data do not conform to the Benford distribution, then questions arise about the process that generated it. Because neutral transformations should preserve conformity to

John V. C. Nye; Charles C. Moul

2007-01-01

200

Quantum number conservation in the statistical bootstrap of fireball decay spectra  

Microsoft Academic Search

Quantum number conservation is considered within the stastistical ; bootstrap model by generalizing the bootstrap equation for the generating ; functional of fireball decay spectra. Explicit solutions are given for the level ; density and the generating functional in the case of additive quantum nunnbers as ; well as isospin conservation. Asymptotic expressions for the level density, the ; inclusive

E. M. Ilgenfritz; J. Kripfganz

1973-01-01

201

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

202

Intramolecular Distances and Dynamics from the Combined Photon Statistics of Single-Molecule FRET and Photoinduced Electron Transfer.  

PubMed

Single-molecule Förster resonance energy transfer (FRET) and photoinduced electron transfer (PET) have developed into versatile and complementary methods for probing distances and dynamics in biomolecules. Here we show that the two methods can be combined in one molecule to obtain both accurate distance information and the kinetics of intramolecular contact formation. In a first step, we show that the fluorescent dyes Alexa 488 and Alexa 594, which are frequently used as a donor and acceptor for single-molecule FRET, are also suitable as PET probes with tryptophan as a fluorescence quencher. We then performed combined FRET/PET experiments with FRET donor- and acceptor-labeled polyproline peptides. The placement of a tryptophan residue into the polyglycylserine tail incorporated in the peptides allowed us to measure both FRET efficiencies and the nanosecond dynamics of contact formation between one of the fluorescent dyes and the quencher. Variation of the linker length between the polyproline and the Alexa dyes and in the position of the tryptophan residue demonstrates the sensitivity of this approach. Modeling of the combined photon statistics underlying the combined FRET and PET process enables the accurate analysis of both the resulting transfer efficiency histograms and the nanosecond fluorescence correlation functions. This approach opens up new possibilities for investigating single biomolecules with high spatial and temporal resolution. PMID:23718771

Haenni, Dominik; Zosel, Franziska; Reymond, Luc; Nettels, Daniel; Schuler, Benjamin

2013-05-29

203

Super-Poissonian Statistics of Photon Emission from Single CdSe-CdS Core-Shell Nanocrystals Coupled to Metal Nanostructures  

NASA Astrophysics Data System (ADS)

We demonstrate that photon antibunching observed for individual nanocrystal quantum dots (NQDs) can be transformed into photon bunching characterized by super-Poissonian statistics when they are coupled to metal nanostructures (MNs). This observation indicates that, while the quantum yield of a biexciton (Q2X) is lower than that of a single exciton (Q1X) in freestanding NQDs, Q2X becomes greater than Q1X in NQDs coupled to MNs. This unique phenomenon is attributed to metal-induced quenching with a rate that scales more slowly with exciton multiplicity than the radiative decay rate and dominates over other nonradiative decay channels for both single excitons and biexcitons.

Park, Young-Shin; Ghosh, Yagnaseni; Chen, Yongfen; Piryatinski, Andrei; Xu, Ping; Mack, Nathan H.; Wang, Hsing-Lin; Klimov, Victor I.; Hollingsworth, Jennifer. A.; Htoon, Han

2013-03-01

204

Analysis of a photon number resolving detector based on fluorescence readout of an ion Coulomb crystal quantum memory inside an optical cavity  

NASA Astrophysics Data System (ADS)

The ability to detect single photons with a high efficiency is a crucial requirement for various quantum information applications. By combining the storage process of a quantum memory for photons with fluorescence-based quantum state measurement, it is, in principle, possible to achieve high-efficiency photon counting in large ensembles of atoms. The large number of atoms can, however, pose significant problems in terms of noise stemming from imperfect initial state preparation and off-resonant fluorescence. We identify and analyse a concrete implementation of a photon number resolving detector based on an ion Coulomb crystal inside a moderately high-finesse optical cavity. The cavity enhancement leads to an effective optical depth of 15 for a finesse of 3000 with only about 1500 ions interacting with the light field. We show that these values allow for essentially noiseless detection with an efficiency larger than 93%. Moderate experimental parameters allow for repetition rates of about 3 kHz, limited by the time needed for fluorescence collection and re-cooling of the ions between trials. Our analysis may lead to the first implementation of a photon number resolving detector in atomic ensembles.

Clausen, Christoph; Sangouard, Nicolas; Drewsen, Michael

2013-02-01

205

Statistical and functional representations of the pattern of auroral energy flux, number flux, and conductivity  

SciTech Connect

Global patterns of the integral energy flux and average energy of precipitating auroral electrons are used to determine the global pattern of the electron-produced, height-integrated Hall and Pedersen conductivities. The conductivities were determined in spatial bins in magnetic local time (MLT)-corrected geomagnetic latitude (CGL) coordinates for all MLTs and for CGLs greater than 50 deg and for seven levels of activity as measured by Kp. On the nightside the two conductivities increase with increasing Kp. The largest conductivities are found near midnight, where the peak value of the Pedersen (Hall) conductivity varies from 3.09 (4.05) mhos to 12.5 (25.9) mhos as Kp varies from 0 > or = 6-. At noon and on much of morning side of the oval the Pedersen and Hall conductivities increase for Kp up to 2 and then decrease for higher Kp. The highest ratios of the Hall to Pedersen conductivity are on the morning side of the oval and at noon. The peak conductivities on the dayside are significant compared to the conductivities produced by solar radiation at all seasons of the year. The global maps of the integral energy flux, integral number flux, and height-integrated Hall and Pedersen conductivities at each level of Kp were fit using both spherical harmonic and Epstein functions. The Epstein functions were found to reproduce better the original maps. At Kp = 2 the distribution of differences between the Epstein function fit and the original data is roughly symmetric about zero with a full width at half maximum of 16 (20)% for the Pedersen (Hall) conductivity and 32(40)% for the integral energy (number) flux. The distribution of difference broadens with increasing and decreasing activity.

Hardy, D.A.; Gussenhoven, M.S.; Raistrick, R.

1987-11-01

206

Uses and misuses of statistics: the case of strontium ranelate and the number needed to treat.  

PubMed

In the last 15 years, several pharmacological agents for the prevention of fractures have been developed and commercialized. Most of them showed to be effective in reducing fracture risk. The enhanced availability of drugs to prevent fractures has generated a fierce competition among pharmaceutical companies to conquer a share of the potential market, often with claims of superiority of a drug over another without direct comparisons. The definitive way to compare different treatments would require randomized head to head trials. These trials are expensive, need large samples and are unlikely to be ever performed. Therefore, it has become a common practice to compare pharmacological agents through observational studies on administrative databases or by the indirect comparison of the results of individual randomised-controlled trials (RCT) and their meta-analyses. These studies may produce evidence of clinical value, complementary to that given by RCT. However, without a proper and complete analysis, they may result in a biased picture of effectiveness and be completely misleading. In this article, we critically disclose how such competition may produce biased and misleading picture of evidence, by reviewing the significance of the number needed to treat, absolute risk reduction and relative risk reduction in relation to vertebral fractures prevention with available drugs. PMID:22080647

Pedrazzoni, M; Giusti, A; Pioli, G

2011-09-01

207

Statistical and functional representations of the pattern of auroral energy flux, number flux, and conductivity  

SciTech Connect

The Hardy et al. (1985) global patterns of the the integral energy flux and average energy of precipitating auroral electrons are used to determine the global pattern of electron-produced, height-integrated Hall and Pedersen conductivities. THe conductivities were determined in spatial bins in magnetic local time (MLT)-corrected geomagnetic latitude (CGL) coordinates for all MLTs and for CGLs greater than 50/sup 0/ and for sevel levels of activity as measured by Kp. The conductivities vary smoothly with latitude and MLT typically having a single peak in latitude within the auroral oval at any MLT. On the nightside the two conductivities increase with increasing Kp. The largest conductivities are found near midnight, where the peak value of the Pederson (Hall) conductivity varies from 3.09 (4.05) mhos to 12.5 (25.9) mhos as Kp varies from 0 to greater than or equal to6-. The peak conductivity decreases with MLT away from midnight with the lowest peak values found postnoon. At noon and on much of the morning side of the oval the Pedersen and Hall conductivities increase for Kp up to 2 and then decrease for higher Kp. The highest ratios of the Hall to Petersen conductivity are on the morning side of the oval and at noon. The peak conductivities on the dayside are significant compared to the conductivities produced by solar radiation at all seasons of the year. The global maps of the integral energy flux, integral number flux, and height-integrated Hall and Pedersen conductivities at each level of Kp were fit using both spherical harmonic and Epstein functions. The Epstein functions were found to reproduce better the original maps.

Hardy, D.A.; Gussenhoven, M.S.; Raistrick, R.; McNeil, W.J.

1987-11-01

208

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

209

Four-Digits or No-Digit Social Security Numbers-Impact on the National Agricultural Statistics Service Record Linkage Maintenance Processes.  

National Technical Information Service (NTIS)

The National Agricultural Statistics Service (NASS) relies on Social Security Numbers (SSNs) and Employer Identification Numbers (EINs) as important matching variables for use in record linkage processing and other list maintenance activities that are con...

B. Iwig D. A. Agreu K. Daniel S. Hoge

2009-01-01

210

Effective atomic numbers for photon energy absorption of essential amino acids in the energy range 1 keV to 20 MeV  

Microsoft Academic Search

Effective atomic numbers for photon energy-absorption (ZPEAeff) of essential amino acids histidine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine have been calculated by a direct method in the energy region of 1keV to 20MeV. The ZPEAeff values have been found to change with energy and composition of the amino acids. The variations of mass energy-absorption coefficient, effective atomic number

S. R. Manohara; S. M. Hanagodimath

2007-01-01

211

Vital and Health Statistics Series 10, Number 250: Summary Health Statistics for U.S. Children: National Health Interview Survey, 2010.  

National Technical Information Service (NTIS)

This report presents both age-adjusted and unadjusted statistics from the 2010 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 ...

2011-01-01

212

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

213

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

214

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

215

Vital and Health Statistics, Series 10, Number 238. Summary Health Statistics for the U.S. Population: National Health Interview Survey, 2007.  

National Technical Information Service (NTIS)

This report presents both age-adjusted and unadjusted health statistics from the 2007 National Health Interview Survey (NHIS) for the civilian noninstitutionalized population of the United States, classified by sex, age, race, Hispanic or Latino origin an...

2008-01-01

216

Vital and Health Statistics, Series 10, Number 243. Summary Health Statistics for the U.S. Population: National Health Interview Survey, 2008.  

National Technical Information Service (NTIS)

This report presents both age-adjusted and unadjusted health statistics from the 2008 National Health Interview Survey (NHIS) for the civilian noninstitutionalized population of the United States, classified by sex, age, race, Hispanic or Latino origin an...

2009-01-01

217

Vital and Health Statistics, Series 10, Number 236. Summary Health Statistics for U.S. Population: National Health Interview Survey, 2006. Data from the National Health Interview Survey.  

National Technical Information Service (NTIS)

This report presents both age-adjusted and unadjusted health statistics from the 2006 National Health Interview Survey (NHIS) for the civilian noninstitutionalized population of the United States, classified by sex, age, race, Hispanic or Latino origin an...

2007-01-01

218

Vital and Health Statistics, Series 10, Number 217. Summary Health Statistics for the U.S. Population: National Health Interview Survey, 2001.  

National Technical Information Service (NTIS)

This report presents health statistics from the 2001 National Health Interview Survey for the civilian noninstitutionalized population of the United States, classified by age, sex, race and Hispanic or Latino origin, family income, poverty status, educati...

2003-01-01

219

Nonclassicality in Raman scattering: Quantum entanglement, squeezing of vacuum fluctuations, sub-shot noise and joint photon-phonon number and integrated-intensity distributions  

NASA Astrophysics Data System (ADS)

Nonclassical properties of the modes in the stimulated, spontaneous and partially spontaneous Raman processes are studied using a completely quantum description of Raman process. Both coherent scattering and chaotic scattering are studied. Nonclassicality in Raman process is observed by means of intermodal entanglement, single mode and intermodal squeezing of vacuum fluctuations, sub-shot noise and wave variances. Joint photon-phonon number and integrated-intensity distributions are then used to illustrate the observed nonclassicalities. Conditional and difference number distributions are provided to illustrate the nonclassical character. The mutual relation between the obtained nonclassicalities and their variations with various parameters are also reported.

Pathak, Anirban; Kr?epelka, Jaromir; Pe?ina, Jan

2013-11-01

220

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

221

A statistical physics perspective on the evolution of ion distributions across low Mach number quasi-perpendicular collisionless shocks  

NASA Astrophysics Data System (ADS)

The heating of directly transmitted ions at low Mach number, perpendicular and quasi-perpendicular shocks has been the subject of previous statistical physics studies. In this paper, we use a Hamiltonian formulation of the ion kinetics for a quasi-perpendicular shock model to derive the general solution to Liouville's equation as a function of six invariants, finding forms of these invariants in terms of the upstream parameters. The ion distribution is expressed as a function of one of these invariants, subject to a Maxwellian upstream boundary condition, and the evolution of the distribution through and downstream of the shock is studied. The momentum-space volume within surfaces of constant probability (related to the temperature) is shown to be inversely proportional to an average value of the canonical momentum associated with motion in the direction normal to the shock plane, generalizing a previous result to three-dimensional phase space. We also study the evolution of the distribution properties numerically, in particular noting that the “twisting” of these surfaces in phase space is the result of the unequal guiding center motion of different parts of the distribution (which is not the case for a fully perpendicular shock). This property provides insight into the damping of oscillations in the mean momentum and the temperature for a quasi-perpendicular model (as the distribution is spread about the central value through gyration) and the observed T$\\perp$ > T$\\parallel$ anisotropy.

Newman, P. R.; Ellacott, S. W.; Wilkinson, W. P.

2011-09-01

222

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

223

Infant Mortality Statistics from the 1998 Period Linked Birth/Infant Death Data Set. National Vital Statistics Reports, Volume 48, Number 12, July 20, 2000.  

National Technical Information Service (NTIS)

The report presents 1998 period infant mortality statistics from the linked birth/infant death data set (linked file) by a variety of maternal and infant characteristics. This report presents infant mortality data by race and Hispanic origin of the mother...

T. J. Matthews S. C. Curtin M. F. MacDorman

2000-01-01

224

True photocounting statistics of multiple on-off detectors  

NASA Astrophysics Data System (ADS)

We derive a closed photocounting formula, including noise counts and a finite quantum efficiency, for photon-number-resolving detectors based on on-off detectors. It applies to detection schemes such as array detectors and multiplexing setups. The result renders it possible to compare the corresponding measured counting statistics with the true photon number statistics of arbitrary quantum states. The photocounting formula is applied to the discrimination of photon numbers of Fock states, squeezed states, and odd coherent states. It is illustrated for coherent states that our formula is indispensable for the correct interpretation of quantum effects observed with such devices.

Sperling, J.; Vogel, W.; Agarwal, G. S.

2012-02-01

225

Spectral overlap in direct measurements of displaced single-photon states  

NASA Astrophysics Data System (ADS)

Many sophisticated quantum states of light display non-classical, characteristic oscillations in their photon statistics altering with respect to the applied displacement. In order to detect these oscillations the mode matching between the studied state and the displacement field plays a crucial role. Only recently the developments in the photon counting techniques have allowed the direct measurements of the photon-number distributions of quantum states. We investigate the properties of displaced single photons by applying time-multiplexed detection of photon statistics and quantify the value of the mode overlap.

Laiho, K.; Avenhaus, M.; Cassemiro, K. N.; Silberhorn, C.

2011-10-01

226

Vital and Health Statistics, Series 1, Number 40. Design and Operation of the National Survey of Early Childhhod Health, 2000.  

National Technical Information Service (NTIS)

This report presents the development, plan, and operation of the National Survey of Early Childhood Health, a module of the State and Local Area Integrated Telephone Survey, conducted by the National Center for Health Statistics, Centers for Disease Contr...

2002-01-01

227

Advance Data from Vital and Health Statistics: Number 302. Office Visits to Orthopedic Surgeons, United States, 1995-96.  

National Technical Information Service (NTIS)

This report describes the utilization of ambulatory medical care services as provided by nonfederally employed, office-based orthopedic surgeons during the period 1995-96. Statistics are presented on selected physician, patient, and visit characteristics....

S. M. Shappert

1999-01-01

228

The effective atomic number revisited in the light of modern photon-interaction cross-section databases.  

PubMed

The effective atomic number, Z(eff), has been calculated for fatty acids and cysteine. It is shown that Z(eff) is a useful parameter for low-Z materials at any energy above 1 keV. Absorption edges of medium-Z elements may complicate the energy dependence of Z(eff) below 10 keV. The notion of Z(eff) is perhaps most useful at energies where Compton scattering is dominating, and where Z(eff) is equal to the mean atomic number, Z, over a wide energy range around 1 MeV. PMID:19828324

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

2009-09-22

229

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.

230

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.

231

Skin Conditions of Youths 12-17, United States. Vital and Health Statistics; Series 11, Number 157.  

ERIC Educational Resources Information Center

|This report of the National Center for Health Statistics presents national estimates of the prevalence of facial acne and other skin lesions among noninstitutionalized youths aged 12-17 years by age, race, sex, geographic region, population size of place of residence, family income, education of parent, overall health, indications of stress,…

Roberts, Jean; Ludford, Jacqueline

232

Water equivalence study of some phantoms based on effective photon energy, effective atomic numbers and electron densities for clinical MV X-ray and Co-60 ?-ray beams  

NASA Astrophysics Data System (ADS)

A previously proposed procedure has been applied to some water equivalent phantoms namely PMMA, Polystyrene, Solid Water (WT1), RW3 and ABS for the first time to compute effective photon energy (Eeff), effective atomic numbers (Zeff) and electron densities (neeff) for different MV X-ray beams and Co-60 gamma beam which are heterogeneous in energy. For the purpose of the present investigation, effective atomic cross-sections of the given materials have been determined first to obtain effective photon energies which were further used for calculation of Zeff and neeff. Similar procedure was adopted for Co-60 ?-rays to check the validity of the present method. Results were found to be quite satisfactory. When it comes to the water equivalence, the Eeff results showed that the RW3 and ABS phantoms are more effective for 6 MV beam whereas RW3 and Polystyrene are more effective for 15 MV and Co-60 beams, respectively. The ABS and WT1 phantoms have better water equivalences than the others according to the Zeff and neeff results, respectively.

Kurudirek, Murat

2013-02-01

233

Continuous-Variable Teleportation of Single-Photon States and AN Accidental Cloning of a Photonic Qubit in Two-Channel Teleportation  

NASA Astrophysics Data System (ADS)

The properties of continuous-variable teleportation of single-photon states are investigated. The output state is different from the input state due to the non-maximal entanglement in the EPR beams. The photon statistics of the teleportation output are determined and the correlation between the field information ? obtained in the teleportation process and the change in photon number is discussed. The results of the output photon statistics are applied to the transmission of a qubit encoded in the polarization of a single photon. The information encoded in the polarization of a single photon can be transferred to a remote location by two-channel continuous variable quantum teleportation. However, the finite entanglement used in the teleportation causes random changes in photon number. If more than one photon appears in the output, the continuous variable teleportation accidentally produces clones of the original input photon. In this paper, it derives the polarization statistics of the N-photon output components and shows that they can be decomposed into an optimal cloning term and completely unpolarized noise. It is found that the accidental cloning of the input photon is nearly optimal at experimentally feasible squeezing levels, indicating that the loss of polarization information is partially compensated by the availability of clones.

Ide, Toshiki

2009-06-01

234

Statistical estimation of the number of streams in the appalachian plateau with fish communities affected by acidic conditions  

SciTech Connect

The objectives of this project are: (1) to use the data collected in the Western Maryland Stream Survey (WMSS) to estimate the number and proportion of stream reaches in the Appalachian Plateau stratum with particular water quality conditions; and (2) to use the data collected in the WMSS to estimate the number and proportion of stream reaches in the Appalachian Plateau stratum that have fish communities affected by adverse water quality (i.e., low pH) or that are unsuitable to support salmonid or cyprinid populations. Population estimation procedures based on a stratified random sample of stream reaches originally sampled in the Maryland Synoptic Stream Chemistry Survey were also provided.

Janicki, A.; Wilson, H.

1994-12-01

235

Statistical Evidence for a Mid-Period Change in Daily Sunspot Group Counts From August 2011 Through August 2012, and the Effect on Daily Relative Sunspot Numbers  

NASA Astrophysics Data System (ADS)

(Abstract only) A combination of statistical counts modeling methods, time series analysis, and t-tests were applied to daily sunspot group counts data obtained from the American Association of Variable Star Observers (AAVSO) Solar Section. The data span the period from August 2011 through August 2012. The analysis investigates whether a statistically significant difference in daily sunspot group counts occurs between the first and second halves of this period. We show that a significant statistical difference exists between the two halves, and this difference also exists in the sunspot number. Also, the rate of change between daily sunspot group counts is shown to be stable between the two periods. These results indicate that between the two periods, the sunspot group count averages and the corresponding sunspot numbers differ, and suggests the sunspot group counts submitted by AAVSO contributors are consistent between the two periods. The change between these time periods may give insight into an apparent bi-modal clustering of sunspots and sunspot groups during this twenty-forth cycle maximum.

Howe, R.

2013-06-01

236

Photon position measure  

SciTech Connect

The positive operator valued measure (POVM) for a photon counting array detector is derived and found to equal photon flux density integrated over pixel area and measurement time. Since photon flux density equals number density multiplied by the speed of light, this justifies theoretically the observation that a photon counting array provides a coarse-grained measurement of photon position. The POVM obtained here can be written as a set of projectors onto a basis of localized states, consistent with the description of photon position in a recent quantum imaging proposal [Tsang, Phys. Rev. Lett. 102, 253601 (2009)]. The wave function that describes a photon counting experiment is the projection of the photon state vector onto this localized basis. Collapse is to the electromagnetic vacuum and not to a localized state, thus violating the textbook rules of quantum mechanics but compatible with the theory of generalized observables and the nonlocalizability of an incoming photon.

Hawton, Margaret [Department of Physics, Lakehead University, Thunder Bay, Ontario, P7B 5E1 (Canada)

2010-07-15

237

Bose-Einstein condensation of photons  

NASA Astrophysics Data System (ADS)

In recent work, we have observed Bose-Einstein condensation (BEC) of a two-dimensional photon gas in an optical microcavity [1]. Here, the transversal motional degrees of freedom of the photons are thermally coupled to the cavity environment by multiple absorption-fluorescence cycles in a dye medium, with the latter serving both as a heat bath and a particle reservoir. The photon energies in this system are found to follow a Bose-Einstein distribution at room temperature. Upon reaching a critical total photon number, a condensation into the transversal ground state of the resonator sets in, while the population of the transversally excited modes roughly saturates. The critical photon number is experimentally verified to agree well with theoretical predictions. Owing to particle exchange between the photon gas and the dye molecules, grandcanonical experimental conditions can approximately be realized in this system. Under these conditions, two markedly different condensate regimes are theoretically expected [2]. On the one hand, this includes a condensate with Poissonian photon number statistics, being the analog to present atomic Bose condensates. Additionally, we predict a second regime with anomalously large condensate fluctuations accompanied by a Bose-Einstein-like photon number distribution that is not observed in present atomic BEC experiments. The crossover between these two regimes, corresponding to the emergence of second-order coherence, depends on the size of the molecular reservoir (e.g. the dye concentration) and is expected to occur at a temperature below the BEC phase transition. In my talk, I will give an update on our experimental work.[4pt] [1] J. Klaers, J. Schmitt, F. Vewinger, and M. Weitz, Nature 468, 545 (2010)[0pt] [2] J. Klaers, J. Schmitt, T. Damm, F. Vewinger, and M. Weitz, Phys. Rev. Lett. 108, 160403 (2012)

Klaers, Jan

2013-03-01

238

Cosmological Photons  

NASA Astrophysics Data System (ADS)

Assumed: photon has electric dipole moment P (Ref. 1) normal to its spin, rotating at photon frequency f, radiating classically. Then: hdf/dt = cdf/dx = -[4(?^3)/3] (?/hc) [(f^2P)^2]; c: standard light speed; x: photon distance from source; ?: vacuum magnetic permeability; h: Planck's constant. Earlier shown (Ref. 2) from Hubble's data: (P'^2)(f'^3) = 8.8E(-39) S.I.; f': photon emission frequency; P': P at emission. Observations of type Ia supernovae and the present study (Refs. 3,4): there must be a relation between P and f; simplest is P^2 = Q(f^n). Q: fitting constant; n: any real number. Comparison of normalized luminosity distances and theoretical coordinate distances gives n = -1.53, with standard deviation 0.013. Speculation: finite graviton half-life T limits general relativistic relations to a sphere of radius cT/2; the universe is infinite and nonexpanding. 1. N. Fortson, P Sandars and S. Barr, Physics Today 56, 33 (June 2003). 2. R. B. Driscoll, Physics Essays (in press). 3. A. G. Riess et al., Astrophysics Journal 687, 665 (2004). 4. R. B. Driscoll, Physics Essays (under review).

Driscoll, Robert

2005-04-01

239

Statistical Criteria for Selecting the Optimal Number of Untreated Subjects Matched to Each Treated Subject When Using Many-to-One Matching on the Propensity Score  

PubMed Central

Propensity-score matching is increasingly being used to estimate the effects of treatments using observational data. In many-to-one (M:1) matching on the propensity score, M untreated subjects are matched to each treated subject using the propensity score. The authors used Monte Carlo simulations to examine the effect of the choice of M on the statistical performance of matched estimators. They considered matching 1–5 untreated subjects to each treated subject using both nearest-neighbor matching and caliper matching in 96 different scenarios. Increasing the number of untreated subjects matched to each treated subject tended to increase the bias in the estimated treatment effect; conversely, increasing the number of untreated subjects matched to each treated subject decreased the sampling variability of the estimated treatment effect. Using nearest-neighbor matching, the mean squared error of the estimated treatment effect was minimized in 67.7% of the scenarios when 1:1 matching was used. Using nearest-neighbor matching or caliper matching, the mean squared error was minimized in approximately 84% of the scenarios when, at most, 2 untreated subjects were matched to each treated subject. The authors recommend that, in most settings, researchers match either 1 or 2 untreated subjects to each treated subject when using propensity-score matching.

Austin, Peter C.

2010-01-01

240

Wide-band suppression of photon-number fluctuations in a high-speed light-emitting diode driven by a constant-current source  

Microsoft Academic Search

We demonstrate experimental results on the generation of sub-Poissonian photon fluxes emanating from an AlGaAs light-emitting diode, which manifest a wide-band (0-100 MHz) noise suppression below the standard quantum limit level despite low current density (~38 A\\/cm2) operation at room temperature. The experimental noise power spectrum is well fitted in terms of the theoretical curve estimated with the quantum mechanical

M. Kobayashi; M. Kohno; Y. Kadoya; M. Yamanishi; J. Abe; T. Hirano

1998-01-01

241

Wide-band suppression of photon-number fluctuations in a high-speed light-emitting diode driven by a constant-current source  

NASA Astrophysics Data System (ADS)

We demonstrate experimental results on the generation of sub-Poissonian photon fluxes emanating from an AlGaAs light-emitting diode, which manifest a wide-band (0-100 MHz) noise suppression below the standard quantum limit level despite low current density (~38 A/cm2) operation at room temperature. The experimental noise power spectrum is well fitted in terms of the theoretical curve estimated with the quantum mechanical Langevin equations.

Kobayashi, M.; Kohno, M.; Kadoya, Y.; Yamanishi, M.; Abe, J.; Hirano, T.

1998-01-01

242

Photon scattering from strongly driven atomic ensembles  

SciTech Connect

The second-order correlation function for light emitted from a strongly and near-resonantly driven dilute cloud of atoms is discussed. Because of the strong driving, the fluorescence spectrum separates into distinct peaks, for which the spectral properties can be defined individually. It is shown that the second-order correlations for various combinations of photons from different spectral lines exhibit bunching together with super-Poissonian or sub-Poissonian photon statistics, tunable by the choice of the detector positions. Additionally, a Cauchy-Schwarz inequality is violated for photons emitted from particular spectral bands. The emitted light intensity is proportional to the square of the number of particles, and thus can potentially be intense. Three different averaging procedures to model ensemble disorder are compared.

Jin Luling [Max-Planck Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Department of Physics, Northwest University, Xi'an 710069, Shaanxi (China); Evers, Joerg; Macovei, Mihai [Max-Planck Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)

2011-10-15

243

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

244

Photon Calorimeter  

DOEpatents

A photon calorimeter (20, 40) is provided that comprises a laminar substrate (10, 22, 42) that is uniform in density and homogeneous in atomic composition. A plasma-sprayed coating (28, 48, 52), 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 (30, 50, 54) are positioned within the plasma-sprayed coatings. The calorimeter is rugged, inexpensive, and equilibrates in temperature very rapidly.

Chow, Tze-Show (Hayward, CA)

1989-01-01

245

Synthetic Estimation of State Health Characteristics Based on the Health Interview Survey. Vital and Health Statistics. Series 2. Data Evaluation and Methods Research. Number 75.  

ERIC Educational Resources Information Center

|Synthetic estimation is a statistical technique that estimates small-area statistics by combining national estimates of the relevant characteristics with estimates of other known characteristics of the small geographic area. The advantages of the synthetic estimation approach to local estimation are its intuitive appeal, its simplicity, and its…

Levy, Paul S.; French, Dwight K.

246

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

247

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

248

Quantum dots in photonic crystals: from single photon sources to single photon nonlinear optics  

NASA Astrophysics Data System (ADS)

A quantum dot strongly coupled to a photonic crystal resonator is used to investigate cavity quantum electro- dynamics phenomena in solid state physics. Nonlinear optical phenomena such as photon blockade and photon induced tunneling are observed in this system. The nonlinearity of this system is sensitive to intra-cavity photon numbers close to unity, and it has been used to demonstrate conditional phase shifts of 28° at a single photon level and a second order auto-correlation of g2(0) = 0.9 in the photon blockade regime.

Majumdar, Arka; Faraon, Andrei; Englund, Dirk; Fushman, Ilya; Vu?kovi?, Jelena

2009-02-01

249

Photon-added detection  

SciTech Connect

The production of conditional quantum states and quantum operations based on the result of measurement is now seen as a key tool in quantum information and metrology. We propose a different type of photon number detector. It functions nondeterministically, but when successful, it has high fidelity. The detector, which makes use of an n-photon auxiliary Fock state and high efficiency homodyne detection, allows a tunable trade-off between fidelity and probability. By sacrificing probability of operation, an excellent approximation to a photon-number detector is achieved.

Branczyk, A.M.; Gilchrist, Alexei; Ralph, T.C. [Centre for Quantum Computer Technology and Department of Physics, University of Queensland, Queensland 4072 (Australia); Osborne, Tobias J. [Centre for Quantum Computer Technology and Department of Physics, University of Queensland, Queensland 4072 (Australia); Department of Mathematics, University of Bristol (United Kingdom)

2003-10-01

250

Vital and Health Statistics, Series 10, Number 224. Summary Health Statistics for the U.S. Population: National Health Interview Survey, 2003. Data from the National Health Interview Survey.  

National Technical Information Service (NTIS)

This report presents both age-adjusted and unadjusted health statistics from the 2003 National Health Interview Survey (NHIS) for the civilian noninstitutionalized population of the United States, classified by age, sex, race and Hispanic or Latino origin...

2005-01-01

251

Vital and Health Statistics, Series 10, Number 214. Summary Health Statistics for the U.S. Population: National Health Interview Survey, 2000. Data from the National Health Interview Survey.  

National Technical Information Service (NTIS)

This report presents health statistics from the 2000 National Health Interview Survey for the civilian noninstitutionalized population of the United States, classified by age, sex, race and Hispanic or Latino origin, family income, poverty status, educati...

C. A. Schoenbom P. F. Adams J. S. Schiller

2003-01-01

252

Avalanche photodiode detection statistics for direct detection laser radar  

NASA Astrophysics Data System (ADS)

The detection statistics of avalanche photodiode detectors when used in laser radar systems are examined. In the laser radar systems considered here, a diffuse hard target is illuminated by a transmitted laser beam and the photons subtended by the receiving aperture and focused onto the detector obey negative-binomial statistics. The specific negative-binomial distribution is determined by the coherence length of the laser and the angular subtense of the target. These received photons are converted into photoelectrons and amplified by the avalanche photodiode which is an imperfect device. Dark current, amplifier, and background-produced noise electrons must be exceeded by the avalanche photodiode output electron pulse for a detection to occur. The required mean number of signal photons from a given negative-binomial target as a function of probability of detection and probability of false alarm is calculated. For perfect photon counters, the probability of detection at high discrete false alarm probabilities is also calculated. It is shown that for probabilities of detection of 0.9, three to five times more laser power may be required than for the generally assumed Poisson signal photons case. At probabilities of detection of 0.3, corresponding to multipulse waveforms, the statistics are independent of the target photon distribution.

Youmans, Douglas G.

1992-06-01

253

Photon Localization in Resonant Media  

NASA Astrophysics Data System (ADS)

Unlike electrons that can be trapped by the Coulomb interaction at atomic sites, photons are not bound by individual particles. They may, however, be strongly scattered at Mie resonances, with the scattering cross section considerably exceeding the geometric cross section. We utilize Mie resonances to localize microwave radiation in low-density quasi-one dimensional samples of randomly positioned dielectric spheres. We explore factors that facilitate photon localization and probe the properties of localized waves. Sharp dips in the ensemble average of transmission and peaks in the average photon transit time are found near the first five Mie resonances. A decisive statistical test of photon localization, based on measurements of the variance of the intensity normalized by its ensemble average value, shows, however, that localization occurs only in a narrow window above the first Mie resonance. Measurements of this localization parameter are compared to measurements of the dimensionless conductance and of the Thouless number in samples with and without absorption. The Thouless number, which is the ratio of the width to the spacing of quasi-modes of a random medium, is obtained from measurements of the field correlation function with frequency shift and of the spacing between resonances in a sealed cavity. In samples with negligible absorption, these parameters coincide. The localization parameters reach a minimum within the window of localization as a result of collective scattering. In the presence of absorption, only the variance of intensity remains a reliable guide to localization. When the sample is cooled to 77 K to reduce absorption, narrow Lorentzian transmission peaks are observed as a result of resonant tunneling through long-lived localized modes. The enhancement of intensity in long-lived modes as the localization threshold is approached is related to sharp line lasing in random amplifying media. In collaboration with Andrey Chabanov.

Genack, Azriel

2002-03-01

254

Photon position measure  

NASA Astrophysics Data System (ADS)

The positive operator valued measure (POVM) for a photon counting array detector is derived and found to equal photon flux density integrated over pixel area and measurement time. Since photon flux density equals number density multiplied by the speed of light, this justifies theoretically the observation that a photon counting array provides a coarse-grained measurement of photon position. The POVM obtained here can be written as a set of projectors onto a basis of localized states, consistent with the description of photon position in a recent quantum imaging proposal [Tsang, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.102.253601 102, 253601 (2009)]. The wave function that describes a photon counting experiment is the projection of the photon state vector onto this localized basis. Collapse is to the electromagnetic vacuum and not to a localized state, thus violating the textbook rules of quantum mechanics but compatible with the theory of generalized observables and the nonlocalizability of an incoming photon.

Hawton, Margaret

2010-07-01

255

Number Watch  

NSDL National Science Digital Library

John Brignell, Professor Emeritus from the Department of Electronics & Computer Science at the University of Southampton, is the author of this informal website "devoted to the monitoring of the misleading numbers that rain down on us via the media." Brignell says he aims to "nail" a few of the "Single Issue Fanatics (SIFs), politicians, bureaucrats, quasi-scientists (junk, pseudo- or just bad)," who use misleading numbers to write catchy articles or who try to keep numbers away from public notice. Since April 2000, he has been posting a "number of the month" as well as a "number for the year," which offer his commentary on media usage of misleading numbers and explanations for why the numbers are misleading. He also posts book reviews and an extensive list of online resources on statistics and statistics education. The FAQ section includes answers to some interesting questions, such as "Is there such a thing as average global temperature?" and some more basic questions such as "What is the Normal Distribution and what is so normal about it?" The Bits and Pieces section includes a variety of short articles on statistics and his definitions for some terms he uses on the website. Visitors are also invited to join the discussion forum (complete with a few advertisements) and view comments by others who want to discuss "wrong numbers in science, politics and the media." A few comments sent to Brignell and his responses are also posted online. This site is also reviewed in the February 11, 2005_NSDL MET Report_.

256

Retention. Report Number One. A Preliminary Report Concerning Descriptive Statistics of those Social and Psychological Attitudes and Background Characteristics Associated with Retention.  

National Technical Information Service (NTIS)

This report examines retention. It provides a socioeconomic profile of the reservists in Naval Reserve Readiness Command Region SEVEN, and a statistical description of their attitudes, opinions and beliefs about the Naval Reserve. After an extensive revie...

M. L. Boykin H. L. Merritt

1979-01-01

257

Vital and Health Statistics, Series 2, Number 146. Estimating Healthy Life Expectancies Using Longitudinal Survey Data: Methods and Techniques in Population Health Measures. Data Evaluation and Methods Research.  

National Technical Information Service (NTIS)

Summary measures of population health are statistics that combine mortality and morbidity to represent overall population health in a single index. Such measures include healthy life expectancy, also called disability-free life expectancy and active life ...

J. H. Madans M. T. Molla

2008-01-01

258

Retrospective analysis of hospital episode statistics, involuntary admissions under the Mental Health Act 1983, and number of psychiatric beds in England 1996-2006  

Microsoft Academic Search

Objective To analyse the number of voluntary and involuntary (detentions under the Mental Health Act 1983) admissions for mental disorders between 1996 and 2006 in England.Design Retrospective analysis.Setting England.Main outcome measures Number of voluntary and involuntary admissions for mental disorders in England’s health service, number of involuntary admissions to private beds, and number of NHS beds for patients with mental

Patrick Keown; Gavin Mercer; Jan Scott

2008-01-01

259

Direct Photons at RHIC  

SciTech Connect

Direct photons are ideal tools to investigate kinematical and thermodynamical conditions of heavy ion collisions since they are emitted from all stages of the collision and once produced they leave the interaction region without further modification by the medium. The PHENIX experiment at RHIC has measured direct photon production in p+p and Au+Au collisions at 200 GeV over a wide transverse momentum (p{sub T}) range. The p+p measurements allow a fundamental test of QCD, and serve as a baseline when we try to disentangle more complex mechanisms producing high p{sub T} direct photons in Au+Au. As for thermal photons in Au+Au we overcome the difficulties due to the large background from hadronic decays by measuring 'almost real' virtual photons which appear as low invariant mass e{sup +}e{sup -} pairs: a significant excess of direct photons is measured above the above next-to-leading order perturbative quantum chromodynamics calculations. Additional insights on the origin of direct photons can be gained with the study of the azimuthal anisotropy which benefits from the increased statistics and reaction plane resolution achieved in RHIC Year-7 data.

Gabor,D.

2008-07-29

260

Auxiliary Entanglement in Photon Pairs for Multi-Photon Entanglement  

SciTech Connect

A growing number of experiments make use of multiple pairs of photons generated in the process of spontaneous parametric down-conversion. We show that entanglement in unwanted degrees of freedom can adversely affect the results of these experiments. We also discuss techniques to reduce or eliminate spectral and spatial entanglement, and we present results from two-photon polarization-entangled source with almost no entanglement in these degrees of freedom. Finally, we present two methods for the generation of four-photon polarization- entangled states. In one of these methods, four-photon can be generated without the need for intermediate two-photon entanglement.

Grice, Warren P [ORNL; Bennink, Ryan S [ORNL; Evans, Philip G [ORNL; Humble, Travis S [ORNL; Schaake, Jason [ORNL

2012-01-01

261

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.

262

Profiles from the Health Statistics Center. Series 7: Community Health Profiles; Number 1: Rhode Island Community Health Profiles, 1976 Edition. Volume 2: Census Tracts.  

National Technical Information Service (NTIS)

Health profiles are presented for each of Rhode Island's 185 census tracts. The profiles in this volume were derived from the following data sets: 1970 census data, 1970-1974 vital statistics natality and mortality data, 1970-1974 communicable disease dat...

1976-01-01

263

Advance Data Number 281. Negative Mood and Urban versus Rural Residence: Using Proximity to Metropolitan Statistical Areas as an Alternative Measure of Residence.  

National Technical Information Service (NTIS)

The purpose of this report is to describe the distribution of reported negative mood by place of residence focusing on proximity to metropolitan statistical areas (MSA'a) as an alternative to the tradiational urban versus rural residence variable using th...

B. S. Jonas R. W. Wilson

1997-01-01

264

National Vital Statistics Reports, Volume 47, Number 22, July 29, 1999. Births and Deaths: Preliminary Data for July 1997-June 1998.  

National Technical Information Service (NTIS)

This report presents preliminary data on births and deaths in the United States from the National Center for Health Statistics (NCHS) for the 12 months ending June 1998. U.S. data on births are shown by age, race, and Hispanic origin of mother. Natality d...

B. L. Smith J. A. Martin S. J. Ventura

1999-01-01

265

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

266

Statistics Indonesia  

NSDL National Science Digital Library

Started in 1997, the Badan Pusat Statistik (BPS-Statistics Indonesia) is a non-departmental Indonesian government institution directly responsible to the Indonesian president. As the law that created this valuable institution stipulates, the BPS is intended to provide data to the government and the public, along cooperating with other international statistical institutions. Visitors looking for statistics on any number of topics will not be disappointed, as the areas covered include agriculture, consumer price indices, employment, energy, foreign trade, mining, population, public finance, tourism, and social welfare. Additionally, there are monthly macro-economic statistical reports for the years from 1998 to 2001 that can be downloaded and viewed as well. The site is rounded out by a collection of some 21 papers from the past four years that analyze various economic data from the country, such as earning data and manufacturing production.

267

Vital Statistics  

Microsoft Academic Search

This article questions the idea that quantitative methods, in particular the analysis of social statistics, is at odds with critical approaches to geography. It argues that numbers-based research is vital to highlight social injustice and oppression and that quantitative research can meet the requirements of critical geography to be reflexive, politically conscious, and activist. The article highlights two issues of

Mark Ellis

2009-01-01

268

Nanopillars photonic crystal waveguides  

Microsoft Academic Search

We present a novel type of a waveguide, which consists of several rows of periodically placed dielectric cylinders. In such a nanopillars photonic crystal waveguide, light confinement is due to the total internal reflection, while guided modes dispersion is strongly affected by waveguide periodicity. Nanopillars waveguide is multimode, where a number of modes is equal to the number of rows

Dmitry N. Chigrin; Andrei V. Lavrinenko; Clivia M. Sotomayor Torres

2004-01-01

269

Accidental cloning of a single-photon qubit in two-channel continuous-variable quantum teleportation  

NASA Astrophysics Data System (ADS)

The information encoded in the polarization of a single photon can be transferred to a remote location by two-channel continuous-variable quantum teleportation. However, the finite entanglement used in the teleportation causes random changes in photon number. If more than one photon appears in the output, the continuous-variable teleportation accidentally produces clones of the original input photon. In this paper, we derive the polarization statistics of the N -photon output components and show that they can be decomposed into an optimal cloning term and completely unpolarized noise. We find that the accidental cloning of the input photon is nearly optimal at experimentally feasible squeezing levels, indicating that the loss of polarization information is partially compensated by the availability of clones.

Ide, Toshiki; Hofmann, Holger F.

2007-06-01

270

Single-photon sources  

NASA Astrophysics Data System (ADS)

The article surveys the state of the art in the design, development and application of devices for deterministically generating single photons on demand. Both the defined function and requisite form of such ‘single-photon’ sources are explained in detail. Their attributes and characteristics, in particular the photon-counting statistics of the light that they generate, are presented in conjunction with the experimental apparatus (most notably the Hanbury-Brown and Twiss interferometer) for measuring them. Promising applications of single-photon sources within quantum key distribution, quantum information processing, as well as metrology and fundamental tests of quantum mechanics, are described. The utility and relative advantages of single-photon sources vis-á-vis more conventional sources of light are explained in terms of application-specific requirements and the respective abilities of different sources to fulfil them. The article collects, classifies and sorts the most significant work towards realizing practical single-photon sources to date. Though emanating from a diverse set of technological disciplines, with different research and application objectives in mind, the relative advantages and drawbacks of each approach are assessed, to give the reader a broad yet coherent and critical review of a rapidly developing research front.

Oxborrow, Mark; Sinclair, Alastair G.

2005-05-01

271

A direct determination of the number of light neutrino families from e+e--->??? 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 Z0 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). Supported by the German Bundesministerium für Forschung und Technologie.

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

272

PHOTON2: A web-based professional development model for photonics technology education  

Microsoft Academic Search

In this paper, we present a web-based teacher professional development model for photonics technology education funded by the National Science Foundation Advanced Technology Education (ATE) program. In response to the rapidly growing demand for skilled photonics technicians, the PHOTON2 project will increase the number of high school teachers and community college faculty across the US proficient in teaching photonics technology

Nicholas M. Massa; Barbara A. Washburn; Marijke Kehrhahn; Judith F. Donnelly; Fenna D. Hanes

2004-01-01

274

Electrotransformation of bacteria by plasmid DNAs: statistical evaluation of a model quantitatively describing the relationship between the number of electrotransformants and DNA concentration  

Microsoft Academic Search

A simple mathematical model for the relationship between the number of transformed cells (nt) and the concentration of transforming DNA (c) was derived on the basis of theoretical consideration on the mechanism of electroporation. The model assumes the adsorption of DNA molecules on the cell surface and penetration of the molecules through the cell wall. The validity and the limits

Bohuslav Rittich; Alena Španová

1996-01-01

275

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

276

An experimental single photon emission computed tomograph method for dynamic 2D fluid flow analysis  

Microsoft Academic Search

We propose a transportable Single Photon Emission Computed Tomograph (SPECT) device dedicated to the reconstruction of a radioactive tracer distribution in a process. The experimental device is realized with 36 collimated sodium iodide detectors mounted around a bi-dimensional cylindrical box which simulates a mixing reactor vessel. The reconstruction is based on a statistical algorithm applied to a small number of

S. Legoupil; G. Pascal; D. Chambellan; D. Bloyet

1997-01-01

277

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

278

Entangled Photon Fluorescence with Organic Conjugated Dendrimers  

NASA Astrophysics Data System (ADS)

The use of entangled photons for spectroscopy is a novel technique with several potential applications in entangled two-photon excited fluorescence microscopy, quantum imaging and remote sensing. Classical TPA depends quadratically on the input photon flux, whereas, non-classical entangled two-photon absorption (ETPA) has a linear dependence on input flux rate. The total TPA rate measured using an entangled photon source is given by the summation of the ETPA rate and the random TPA rate. This work focuses on the entangled two-photon absorption cross-section and the entangled two-photon fluorescence efficiency of a G1 Dendrimer. From these results, it is shown that the entangled two-photon excited fluorescence of the G1 Dendrimer has a linear dependence at low input photon fluxes. This result has great impact on spectroscopy where the need for small numbers of photons is great, such as microscopy and sensing.

Upton, Leslie; Goodson, Theodore

2012-02-01

279

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

280

fJ/bit photonic platform based on photonic crystals  

NASA Astrophysics Data System (ADS)

Recently, photonic crystals have enabled a variety of ultrasmall photonic devices with extremely small energy consumption of ~fJ/bit level, suggesting that we can integrate a vast number of nanophotonic devices in a single chip. This technology may give us a way to introduce high-speed integrated nanophotonics in an information chip, which will be crucial in future ICT.

Notomi, Masaya

2011-09-01

281

Dow Corning photonics: the silicon advantage in automotive photonics  

Microsoft Academic Search

The Automotive Market offers several opportunities for Dow Corning to leverage the power of silicon-based materials. Dow Corning Photonics Solutions has a number of developments that may be attractive for the emergent photonics needs in automobiles, building on 40 years of experience as a leading Automotive supplier with a strong foundation of expertise and an extensive product offering- from encapsulents

Terry V. Clapp; Rene Paquet; Ann Norris; Babette Pettersen

2005-01-01

282

Folding Photons  

SciTech Connect

Scientists have shown that wrinkles and folds can be used to maximize the absorption of low-energy photons by efficiently redirecting them into a thin absorbing film. This inexpensive technique for structuring photonic substrates could be used to increase the efficiency of many organic photovoltaic cells.

Gregg, B. A.; van de Lagemaat, J.

2012-05-01

283

Chalcogenide photonics  

Microsoft Academic Search

The unique and striking material properties of chalcogenide glasses have been studied for decades, providing applications in the electronics industry, imaging and more recently in photonics. This Review summarizes progress in photonic devices that exploit the unique optical properties of chalcogenide glasses for a range of important applications, focusing on recent examples in mid-infrared sensing, integrated optics and ultrahigh-bandwidth signal

Benjamin J. Eggleton; Barry Luther-Davies; Kathleen Richardson

2011-01-01

284

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

285

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

286

Photon wave mechanics and position eigenvectors  

Microsoft Academic Search

One and two photon wave functions are derived by projecting the quantum state vector onto simultaneous eigenvectors of the number operator and a recently constructed photon position operator [Phys. Rev. A 59, 954 (1999)] that couples spin and orbital angular momentum. While only the Landau-Peierls wave function defines a positive definite photon density, a similarity transformation to a biorthogonal field-potential

Hawton

2007-01-01

287

Quantification of fluorescent samples by photon-antibunching  

NASA Astrophysics Data System (ADS)

Typical problems in molecular biology, like oligomerization of proteins, appear on non-resolvable length scales. Therefore a method which allows counting numbers of fluorescent emitters beyond this barrier can help to unveil these questions. One approach engaging this task makes use of the photon antibunching (PAB) effect. Most fluorophores are single photon emitters. Therefore upon a narrow excitation pulse they might only run through one excitation cycle and emit one photon at a time. This behavior is known as PAB. By analyzing coincident events of photon detections (Coincidence Analysis, CCA ) over many excitation cycles the number of fluorophores residing in the confocal volume can be estimated. Simulations have shown that up to 40 fluorophores can be distinguished with a reasonable error. In follow-up experiments five fluorophores could be distinguished by CCA. In this work the method is applied to a whole sample set and statistical variance and robustness are determined. CCA is critical to several parameters like photo stability, background noise, label efficiency and photopysical properties of the dye, like brightness and blinking. Therefore a reasonable scheme for analysis is introduced and setup parameters are optimized. To proof the superiority of CCA, it has been applied to estimate the number of dyes for a well-defined probe and the results have been compared with bleach step analysis (BS analysis), a method based on the ability to observe single bleach-steps.

Kurz, Anton; Schwering, Michael; Herten, Dirk-Peter

2012-02-01

288

Statistical Properties of the Squeezing-enhanced Coherent State  

NASA Astrophysics Data System (ADS)

In this paper, we introduce theoretically a new kind of squeezing-enhanced coherent state (SECS) which is generated by operating a new-type squeezing operator on a coherent state. Based on the normally ordered form of density operator of SECS, we study its statistical properties by the quadrature squeezing, the photon-number distribution, second-order correlation function, and the Wigner function. Comparing with the usual squeezed coherent state (SCS), all results indicate that SECS indeed has stronger squeezing and shows some new statistical properties.

Li, Heng-Mei; Yan, Peng-Fei; Xu, Xue-Fen

2012-12-01

289

Photon acceleration from rest  

SciTech Connect

In this paper we present a new mechanism for generating coherent radiation from a laser-ionized gas-filled capacitor array. The scheme directly converts a static electric field of wave number {ital k}{sub 0} into coherent radiation pulses. The physical mechanism is analogous to photon acceleration in plasma waves, and in this sense, photons are accelerated from zero frequency (zero energy) to a frequency {omega}{sup 2}{sub {ital p}}/2{ital k}{sub 0}{ital c}. The frequency (energy) of the photons is controlled by the gas pressure and/or capacitor spacing and has broad tunability over several orders of magnitude. We calculate the output frequency and power and compare theoretical predictions to 2D PIC simulations. {copyright} 1995 {ital American Institute of Physics}.

Katsouleas, T.; Lai, C.H. [Department of Electrical Engineering-Electrophysics, University of Southern California Los Angeles, California 90089 (United States); Dawson, J.M.; Mori, W.B. [UCLA Department of Electrical Engineering, Los Angeles, California 90024 (United States)

1995-06-01

290

Nonlinear silicon photonics  

NASA Astrophysics Data System (ADS)

An intriguing optical property of silicon is that it exhibits a large third-order optical nonlinearity, with orders-ofmagnitude larger than that of silica glass in the telecommunication band. This allows efficient nonlinear optical interaction at relatively low power levels in a small footprint. Indeed, we have witnessed a stunning progress in harnessing the Raman and Kerr effects in silicon as the mechanisms for enabling chip-scale optical amplification, lasing, and wavelength conversion - functions that until recently were perceived to be beyond the reach of silicon. With all the continuous efforts developing novel techniques, nonlinear silicon photonics is expected to be able to reach even beyond the prior achievements. Instead of providing a comprehensive overview of this field, this manuscript highlights a number of new branches of nonlinear silicon photonics, which have not been fully recognized in the past. In particular, they are two-photon photovoltaic effect, mid-wave infrared (MWIR) silicon photonics, broadband Raman effects, inverse Raman scattering, and periodically-poled silicon (PePSi). These novel effects and techniques could create a new paradigm for silicon photonics and extend its utility beyond the traditionally anticipated applications.

Tsia, Kevin K.; Jalali, Bahram

2010-04-01

291

Single-photon filtering by a cavity quantum electrodynamics system  

SciTech Connect

The nonlinear dynamics of a classical photon pulse in a cavity-QED system is investigated theoretically. It is shown that this system can work as a single-photon filter, which drastically suppresses the multiple-photon probability of the output. The output photon statistics is sensitive to the input pulse length. A suitable choice of pulse length produces a photon pulse with the single-photon probability of 0.32, while the multiple-photon probability is suppressed to 0.01.

Koshino, Kazuki [College of Liberal Arts and Sciences, Tokyo Medical and Dental University, 2-8-30 Konodai, Ichikawa 272-0827 (Japan) and PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama 332-0012 (Japan)

2008-02-15

292

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

293

International Statistical Institute - Glossary of Statistical Terms  

NSDL National Science Digital Library

This site shows the International Statistical Institutes alphabetical list of technical terms showing the translation in a number of languages. The page covers a myriad of different terms and our translated into many languages such as: English, French, German, Dutch, Italian, Spanish, Catalan, Portuguese, Romanian, Danish, Norwegian, Swedish, Greek and many more. This is a nice reference site for anyone interested in statistics.

2009-12-08

294

Photonic module: An on-demand resource for photonic entanglement  

SciTech Connect

Photonic entanglement has a wide range of applications in quantum computation and communication. Here we introduce a device: the photonic module, which allows for the rapid, deterministic preparation of a large class of entangled photon states. The module is an application independent, ''plug and play'' device, with sufficient flexibility to prepare entanglement for all major quantum computation and communication applications in a completely deterministic fashion without number-discriminated photon detection. We present two alternative constructions for the module, one using free-space components and one in a photonic band-gap structure. The natural operation of the module is to generate states within the stabilizer formalism and we present an analysis on the cavity requirements to experimentally realize this device.

Devitt, Simon J.; Greentree, Andrew D.; Hollenberg, Lloyd C. L. [Centre for Quantum Computing Technology, School of Physics, University of Melbourne, Victoria 3010 (Australia); Ionicioiu, Radu [Hewlett-Packard Laboratories, Filton Road, Stoke Gifford, Bristol BS34 8QZ (United Kingdom); O'Brien, Jeremy L. [Centre for Quantum Photonics, H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering, University of Bristol, Merchant Venturers Building, Woodland Road, Bristol BS8 1UB (United Kingdom); Munro, William J. [Hewlett-Packard Laboratories, Filton Road, Stoke Gifford, Bristol BS34 8QZ (United Kingdom); National Institute of Informatics, 2-1-2 Hitotsubashi, Chiyoda-ku, Tokyo 101-8430 (Japan)

2007-11-15

295

Photonic phased array technology for radio telescope systems  

NASA Astrophysics Data System (ADS)

The application of novel photonic technologies in radio telescope systems becomes more-and-more attractive thanks to the improvement of the performance of photonic signal transport and photonic signal processing technologies and a reduction of their cost level. For the development of photonic technology for radio telescopes like the SKA, a photonic phased array roadmap has been defined at ASTRON, according to which a number of photonic technology demonstrator are built and experimentally investigated. In one of the first steps of the roadmap, a discrete IC component based photonic phased array tile with optical analog links and photonic beamformer was developed. Currently a photonic phased array tile is being built with hybrid integrated optical transmitter and photonic beamformer IC technology. In this paper, the photonic phased array technology roadmap will be described. In addition, a description will be given of both photonic phased array demonstrator systems and experimental results will be given.

Maat, D. H. P.; Dijkstra, K.

2012-09-01

296

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

297

Green photonics  

NASA Astrophysics Data System (ADS)

Photonics, the broad merger of electronics with the optical sciences, encompasses such a wide swath of technology that its impact is almost universal in our everyday lives. This is a broad overview of some aspects of the industry and their contribution to the ‘green’ or environmental movement. The rationale for energy conservation is briefly discussed and the impact of photonics on our everyday lives and certain industries is described. Some opinions from industry are presented along with market estimates. References are provided to some of the most recent research in these areas.

Quan, Frederic

2012-02-01

298

Natural photonic crystals  

NASA Astrophysics Data System (ADS)

Photonic structures appeared in nature several hundred millions years ago. In the living world, color is used for communication and this important function strongly impacts the individual chances of survival as well as the chances to reproduce. This has a statistical influence on species populations. Therefore, because they are involved in evolution, natural color-generating structures are - from some point of view - highly optimized. In this short review, a survey is presented of the development of natural photonic crystal-type structures occurring in insects, spiders, birds, fishes and other marine animals, in plants and more, from the standpoint of light-waves propagation. One-, two-, and three-dimensional structures will be reviewed with selected examples.

Vigneron, Jean Pol; Simonis, Priscilla

2012-10-01

299

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

300

Cancer Statistics  

MedlinePLUS

... Rates Continue to Drop SEER Cancer Statistics Review, 1975-2010 Did You Know? Video Series Cancer Statistics ... and survival from the SEER Cancer Statistics Review, 1975-2010. Play Pause Volume Up Volume Down Mute ...

301

Photonic Floquet topological insulators  

NASA Astrophysics Data System (ADS)

Topological insulators are a new phase of matter, with the striking property that conduction of electrons occurs only on the surface. In two dimensions, surface electrons in topological insulators do not scatter despite defects and disorder, providing robustness akin to superconductors. Topological insulators are predicted to have wideranging applications in fault-tolerant quantum computing and spintronics. Recently, large theoretical efforts were directed towards achieving topological insulation 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. However, since magnetic effects are very weak at optical frequencies, realizing photonic topological insulators with scatterfree edge states requires a fundamentally different mechanism - one that is free of magnetic fields. Recently, a number of proposals for photonic topological transport have been put forward. Specifically, one suggested temporally modulating 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, where temporal variations in solidstate systems induce topological edge states. Here, we propose and experimentally demonstrate the first external field-free photonic topological insulator 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 acts as `time'. Thus the waveguides' helicity breaks zreversal symmetry in the sense akin to Floquet Topological Insulators. This structure results in scatter-free, oneway edge states that are topologically protected from scattering.

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

2013-09-01

302

Photon Wave Mechanics  

Microsoft Academic Search

In contrast to wave functions in nonrelativistic quantum mechanics interpreted as probability amplitudes, wave functions in relativistic quantum mechanics have generalized meanings such as charge-density amplitudes, energy-density amplitudes as well as particle-number density amplitudes, etc. Applying electromagnetic field intensities we construct a photon wave function, it corresponds to the (1,0)+(0,1) spinor representation of the electromagnetic field, and can be interpreted

Zhi-Yong Wang; Cai-Dong Xiong; Ole Keller

2005-01-01

303

Engineered quantum dot single-photon sources  

NASA Astrophysics Data System (ADS)

Fast, high efficiency and low error single-photon sources are required for the implementation of a number of quantum information processing applications. The fastest triggered single-photon sources to date have been demonstrated using epitaxially grown semiconductor quantum dots (QDs), which can be conveniently integrated with optical microcavities. Recent advances in QD technology, including demonstrations of high temperature and telecommunications wavelength single-photon emission, have made QD single-photon sources more practical. Here we discuss the applications of single-photon sources and their various requirements, before reviewing the progress made on a QD platform in meeting these requirements.

Buckley, Sonia; Rivoire, Kelley; Vu?kovi?, Jelena

2012-12-01

304

Dilated Networks for Photonic Switching  

Microsoft Academic Search

We present some novel architectures for rearrangeably nonblocking multistage photonic space switches implemented using arrays ofTi:LiNbO_{3}directional couplers. Multistage networks, studied mostly in the electronic domain, are obtained by minimizing the number of 2 × 2 elements needed to implement a switch. Unfortunately, straightforward extensions of these networks to the photonic domain show that the switch size has to be severely

K. Padmanabhan; A. Netravali

1987-01-01

305

Photon collider at TESLA  

NASA Astrophysics Data System (ADS)

High energy photon colliders (??,?e) based on backward Compton scattering of laser light is a very natural addition to e+e- linear colliders. In this report, we consider this option for the TESLA project. Recent study has shown that the horizontal emittance in the TESLA damping ring can be further decreased by a factor of four. In this case, the /?? luminosity in the high energy part of spectrum can reach about (1/3)Le+e-. Typical cross-sections of interesting processes in /?? collisions are higher than those in e+e- collisions by about one order of magnitude, so the number of events in /?? collisions will be more than that in e+e- collisions. Photon colliders can, certainly, give additional information and they are the best for the study of many phenomena. The main question is now the technical feasibility. The key new element in photon colliders is a very powerful laser system. An external optical cavity is a promising approach for the TESLA project. A free electron laser is another option. However, a more straightforward solution is ``an optical storage ring (optical trap)'' with a diode pumped solid state laser injector which is today technically feasible. This paper briefly reviews the status of a photon collider based on the linear collider TESLA, its possible parameters and existing problems.

Telnov, Valery

2001-10-01

306

Vesicle Photonics  

NASA Astrophysics Data System (ADS)

Amphiphiles, under appropriate conditions, can self-assemble into nanoscale thin membrane vessels (vesicles) that encapsulate and hence protect and transport molecular payloads. Vesicles assemble naturally within cells but can also be artificially synthesized. In this article, we review the mechanisms and applications of light-field interactions with vesicles. By being associated with light-emitting entities (e.g., dyes, fluorescent proteins, or quantum dots), vesicles can act as imaging agents in addition to cargo carriers. Vesicles can also be optically probed on the basis of their nonlinear response, typically from the vesicle membrane. Light fields can be employed to transport vesicles by using optical tweezers (photon momentum) or can directly perturb the stability of vesicles and hence trigger the delivery of the encapsulated payload (photon energy). We conclude with emerging vesicle applications in biology and photochemical microreactors.

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

2013-07-01

307

CMOS photonics  

Microsoft Academic Search

Light will be connecting CMOS chips sooner than you think. While every major semiconductor company is exploring silicon photonics in their research labs, Luxtera has implemented a practical version of the technology in a high-volume production CMOS process. The base process is Freescale's 0.13 ?m SOI CMOS, used to manufacture many of their high-performance PowerPC processors. In addition to the

C. Gunn

2005-01-01

308

Photon-aided and photon-inhibited tunneling of photons  

NASA Astrophysics Data System (ADS)

In light of the interest in the transport of single photons in arrays of waveguides, fiber couplers, photonic crystals, etc., we consider the quantum mechanical process of the tunneling of photons through evanescently or otherwise coupled structures. We specifically examine the issue of tunneling between two structures when one structure already contains few photons. We demonstrate the possibility of both photon-aided and photon-inhibited tunneling of photons. The bosonic nature of photons enhances the tunneling probability. We also show how the multiphoton tunneling probability can be either enhanced or inhibited due to the presence of photons. We find similar results for higher-order tunneling. Finally, we show that the presence of a squeezed field changes the nature of tunneling considerably.

Liu, Xuele; Agarwal, G. S.

2013-06-01

309

Statistical Inference  

Microsoft Academic Search

\\u000a An important application of probability theory is the use of statistics in science, in particular classical statistics as\\u000a devised by Fisher and Neyman and Pearson. Good introductions to this type of statistics are provided in (Barnett, 1999) and\\u000a in (Mood et al., 1974). We should emphasize that classical statistics is not an uncontroversial tool for reasoning statistically,\\u000a and that it

Rolf Haenni; Jan-Willem Romeijn; Gregory Wheeler; Jon Williamson

310

Teleportation-based number-state manipulation with number-sum measurement  

SciTech Connect

We examine various manipulations of photon number states which can be implemented by teleportation technique with number-sum measurement. The preparations of the Einstein-Podolsky-Rosen resources as well as the number-sum measurement resulting in projection to certain Bell state may be done conditionally with linear optical elements, i.e., beam splitters, phase shifters, and zero-one-photon detectors. Squeezed vacuum states are used as primary entanglement resource, while single-photon sources are not required.

Kitagawa, Akira; Yamamoto, Katsuji [Department of Nuclear Engineering, Kyoto University, Kyoto 606-8501 (Japan)

2003-10-01

311

Photon wave mechanics and position eigenvectors  

SciTech Connect

One and two photon wave functions are derived by projecting the quantum state vector onto simultaneous eigenvectors of the number operator and a recently constructed photon position operator [Phys. Rev. A 59, 954 (1999)] that couples spin and orbital angular momentum. While only the Landau-Peierls wave function defines a positive definite photon density, a similarity transformation to a biorthogonal field-potential pair of positive frequency solutions of Maxwell's equations preserves eigenvalues and expectation values. We show that this real space description of photons is compatible with all of the usual rules of quantum mechanics and provides a framework for understanding the relationships amongst different forms of the photon wave function in the literature. It also gives a quantum picture of the optical angular momentum of beams that applies to both one photon and coherent states. According to the rules of quantum mechanics, this wave function gives the probability to count a photon at any position in space.

Hawton, Margaret [Department of Physics, Lakehead University, Thunder Bay, Ontario, P7B 5E1 (Canada)

2007-06-15

312

Limits of heralded single-photon sources based on parametric photon-pair generation  

SciTech Connect

We derive calculations on the statistics of a heralded single-photon source based on parametric photon-pair generation. These calculations highlight fundamental and practical limits for these sources and show which physical parameters can be optimized to improve the quality of a real source.

Virally, Stephane; Lacroix, Suzanne; Godbout, Nicolas [COPL, Departement de Genie Physique, Ecole Polytechnique de Montreal, Case Postale 6079, Succursale Centre-Ville, Montreal, Quebec H3C 3A7 (Canada)

2010-01-15

313

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

314

Optics of photonic quasicrystals  

NASA Astrophysics Data System (ADS)

The physics of periodic systems are of fundamental importance and result in various phenomena that govern wave transport and interference. However, deviations from periodicity may result in higher complexity and give rise to a number of surprising effects. One such deviation can be found in the field of optics in the realization of photonic quasicrystals, a class of structures made from building blocks that are arranged using well-designed patterns but lack translational symmetry. Nevertheless, these structures, which lie between periodic and disordered structures, still show sharp diffraction patterns that confirm the existence of wave interference resulting from their long-range order. In this Review, we discuss the beautiful physics unravelled in photonic quasicrystals of one, two and three dimensions, and describe how they can influence optical transmission and reflectivity, photoluminescence, light transport, plasmonics and laser action.

Vardeny, Z. Valy; Nahata, Ajay; Agrawal, Amit

2013-03-01

315

The Statistical Drake Equation  

Microsoft Academic Search

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

Claudio Maccone

2010-01-01

316

Statistical Summaries: Public Institutions.  

ERIC Educational Resources Information Center

|This document, presents a statistical portrait of the Virginia's 17 public higher education institutions. Data provided include: enrollment figures (broken down in categories such as sex, residency, full- and part-time status, residence, ethnicity, age, and level of postsecondary education); FTE figures; admissions statistics (such as number

Virginia State Council of Higher Education, Richmond.

317

Hate Crime Statistics, 1998.  

National Technical Information Service (NTIS)

Statistical publications like Hate Crime Statistics are designed to be factual presentations of data. Their purpose is not to evoke emotion, make pleas, or sway opinion. The neat columns and rows of numbers in this book cannot convey the suffering experie...

1998-01-01

318

Statistical Geneticist: Janet Sinsheimer  

NSDL National Science Digital Library

This is a PDF interview, PowerPoint slide set, and webpage biography of a statistical geneticist, detailing the importance of scientists fluent in the analysis of numbers to organize data and design studies.

2012-05-02

319

Integrated spatial multiplexing of heralded single-photon sources  

NASA Astrophysics Data System (ADS)

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.

2013-10-01

320

Single-photon sources  

Microsoft Academic Search

The concept of the photon, central to Einstein's explanation of the photoelectric effect, is exactly 100 years old. Yet, while photons have been detected individually for more than 50 years, devices producing individual photons on demand have only appeared in the last few years. New concepts for single-photon sources, or 'photon guns', have originated from recent progress in the optical

Brahim Lounis; Michel Orrit

2005-01-01

321

Statistical Software.  

ERIC Educational Resources Information Center

|This buyer's guide to seven major types of statistics software packages for microcomputers reviews Edu-Ware Statistics 3.0; Financial Planning; Speed Stat; Statistics with DAISY; Human Systems Dynamics package of Stats Plus, ANOVA II, and REGRESS II; Maxistat; and Moore-Barnes' MBC Test Construction and MBC Correlation. (MBR)|

Callamaras, Peter

1983-01-01

322

Mindless statistics  

Microsoft Academic Search

Statistical rituals largely eliminate statistical thinking in the social sciences. Rituals are indispensable for identification with social groups, but they should be the subject rather than the procedure of science. What I call the “null ritual” consists of three steps: (1) set up a statistical null hypothesis, but do not specify your own hypothesis nor any alternative hypothesis, (2) use

Gerd Gigerenzer; Max Planck

2004-01-01

323

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…

Petocz, Peter; Sowey, Eric

2008-01-01

324

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

325

SIDS Statistics  

MedlinePLUS

... Alaska Natives (National Center for Health Statistics' (NCHS) linked birth/infant death data . See Chart 2 below. More information on these ... 2013. Infant mortality statistics from the 2009 period linked birth/infant death data set . National Vital Statistics Reports 61(8):1– ...

326

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

327

A statistical estimation approach for quantitative concentrations of compounds lacking authentic standards/surrogates based on linear correlations between directly measured detector responses and carbon number of different functional groups.  

PubMed

A statistical approach was investigated to estimate the concentration of compounds lacking authentic standards/surrogates (CLASS). As a means to assess the reliability of this approach, the response factor (RF) of CLASS is derived by predictive equations based on a linear regression (LR) analysis between the actual RF (by external calibration) of 18 reference volatile organic compounds (VOCs) consisting of six original functional groups and their physicochemical parameters ((1) carbon number (CN), (2) molecular weight (MW), and (3) boiling point (BP)). If the experimental bias is estimated in terms of percent difference (PD) between the actual and projected RF, the least bias for 18 VOCs is found from CN (17.9 ± 19.0%). In contrast, the PD values against MW and BP are 40.6% and 81.5%, respectively. Predictive equations were hence derived via an LR analysis between the actual RF and CN for 29 groups: (1) one group consisting of all 18 reference VOCs, (2) three out of six original functional groups, and (3) 25 groups formed randomly from the six functional groups. The applicability of this method was tested by fitting these 29 equations into each of the six original functional groups. According to this approach, the mean PD for 18 compounds dropped as low as 5.60 ± 5.63%. This approach can thus be used as a practical tool to assess the quantitative data for CLASS. PMID:23766682

Kim, Yong-Hyun; Kim, Ki-Hyun

2013-05-12

328

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

329

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

330

Investigation of variance reduction techniques for Monte Carlo photon dose calculation using XVMC.  

PubMed

Several variance reduction techniques, such as photon splitting, electron history repetition, Russian roulette and the use of quasi-random numbers are investigated and shown to significantly improve the efficiency of the recently developed XVMC Monte Carlo code for photon beams in radiation therapy. It is demonstrated that it is possible to further improve the efficiency by optimizing transpon parameters such as electron energy cut-off, maximum electron energy step size, photon energy cut-off and a cut-off for kerma approximation, without loss of calculation accuracy. These methods increase the efficiency by a factor of up to 10 compared with the initial XVMC ray-tracing technique or a factor of 50 to 80 compared with EGS4/PRESTA. Therefore, a common treatment plan (6 MV photons, 10 x 10 cm2 field size, 5 mm voxel resolution, 1% statistical uncertainty) can be calculated within 7 min using a single CPU 500 MHz personal computer. If the requirement on the statistical uncertainty is relaxed to 2%, the calculation time will be less than 2 min. In addition, a technique is presented which allows for the quantitative comparison of Monte Carlo calculated dose distributions and the separation of systematic and statistical errors. Employing this technique it is shown that XVMC calculations agree with EGSnrc on a sub-per cent level for simulations in the energy and material range of interest for radiation therapy. PMID:10958187

Kawrakow, I; Fippel, M

2000-08-01

331

Investigation of variance reduction techniques for Monte Carlo photon dose calculation using XVMC  

NASA Astrophysics Data System (ADS)

Several variance reduction techniques, such as photon splitting, electron history repetition, Russian roulette and the use of quasi-random numbers are investigated and shown to significantly improve the efficiency of the recently developed XVMC Monte Carlo code for photon beams in radiation therapy. It is demonstrated that it is possible to further improve the efficiency by optimizing transport parameters such as electron energy cut-off, maximum electron energy step size, photon energy cut-off and a cut-off for kerma approximation, without loss of calculation accuracy. These methods increase the efficiency by a factor of up to 10 compared with the initial XVMC ray-tracing technique or a factor of 50 to 80 compared with EGS4/PRESTA. Therefore, a common treatment plan (6 MV photons, 10×10 cm2 field size, 5 mm voxel resolution, 1% statistical uncertainty) can be calculated within 7 min using a single CPU 500 MHz personal computer. If the requirement on the statistical uncertainty is relaxed to 2%, the calculation time will be less than 2 min. In addition, a technique is presented which allows for the quantitative comparison of Monte Carlo calculated dose distributions and the separation of systematic and statistical errors. Employing this technique it is shown that XVMC calculations agree with EGSnrc on a sub-per cent level for simulations in the energy and material range of interest for radiation therapy.

Kawrakow, Iwan; Fippel, Matthias

2000-08-01

332

Physics at high energy photon photon colliders  

SciTech Connect

I review the physic prospects for high energy photon photon colliders, emphasizing results presented at the LBL Gamma Gamma Collider Workshop. Advantages and difficulties are reported for studies of QCD, the electroweak gauge sector, supersymmetry, and electroweak symmetry breaking.

Chanowitz, M.S.

1994-06-01

333

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

334

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

335

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

336

Decoherence in collective quantum memories for photons  

Microsoft Academic Search

The influence of decoherence on quantum memories for photons based on atomic ensembles is discussed. It is shown that despite the large entanglement of the collective storage states, corresponding to single photons or nonclassical states of light, the sensitivity to decoherence does not scale with the number of atoms. This is due to the existence of equivalence classes of storage

Claudia Mewes; Michael Fleischhauer

2005-01-01

337

Photon emitting, absorption, and reconstruction of photons  

Microsoft Academic Search

Photon cannot keep itself unchanged from emission to absorption. The information encoded on the photon is also changed due to interaction with environment. There has no definitely demonstration that the photon being absorbed is the original one from ideal light source since the quantum mechanics itself is an indeterminate theory that the physical measurement is only the probability. We divide

Changjun Liao; Jindong Wang; Zhengjun Wei; Jianping Guo

2007-01-01

338

Entangled-photon compressive ghost imaging  

SciTech Connect

We have experimentally demonstrated high-resolution compressive ghost imaging at the single-photon level using entangled photons produced by a spontaneous parametric down-conversion source and using single-pixel detectors. For a given mean-squared error, the number of photons needed to reconstruct a two-dimensional image is found to be much smaller than that in quantum ghost imaging experiments employing a raster scan. This procedure not only shortens the data acquisition time, but also suggests a more economical use of photons for low-light-level and quantum image formation.

Zerom, Petros [Institute of Optics, University of Rochester, Rochester, New York 14627 (United States); Chan, Kam Wai Clifford [Rochester Optical Manufacturing Company, 1260 Lyell Avenue, Rochester, New York 14606 (United States); Howell, John C. [Department of Physics and Astronomy, University of Rochester, 500 Wilson Boulevard, Rochester, New York 14627 (United States); Boyd, Robert W. [Institute of Optics, University of Rochester, Rochester, New York 14627 (United States); Department of Physics and Astronomy, University of Rochester, 500 Wilson Boulevard, Rochester, New York 14627 (United States); Department of Physics, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5 (Canada)

2011-12-15

339

Entangled-photon compressive ghost imaging  

NASA Astrophysics Data System (ADS)

We have experimentally demonstrated high-resolution compressive ghost imaging at the single-photon level using entangled photons produced by a spontaneous parametric down-conversion source and using single-pixel detectors. For a given mean-squared error, the number of photons needed to reconstruct a two-dimensional image is found to be much smaller than that in quantum ghost imaging experiments employing a raster scan. This procedure not only shortens the data acquisition time, but also suggests a more economical use of photons for low-light-level and quantum image formation.

Zerom, Petros; Chan, Kam Wai Clifford; Howell, John C.; Boyd, Robert W.

2011-12-01

340

The relation between properties of Gentile statistics and fractional statistics of anyon  

NASA Astrophysics Data System (ADS)

In this paper, we discuss the relationship of two kinds of intermediate-statistics, the Gentile statistics and the fractional statistics of anyons. The anyon winding number representation is introduced. We construct the transformation between anyon winding number representation and the occupation number representation of particles of Gentile statistics. We study intermediate-statistics quantum bracket and coherent states for anyons in the winding number representation. We demonstrate that anyons can be simulated by Gentile statistics with a geometric phase.

Shen, Yao; Ai, Qing; Long, Gui Lu

2010-04-01

341

Number Models  

NSDL National Science Digital Library

Students are given a worksheet with a representation of a number in base-ten blocks. Students are asked to write the number with numerals and determine how the number changes, when blocks are added and taken away.

Sherdan, Danielle

2010-07-26

342

Observation of eight-photon entanglement  

NASA Astrophysics Data System (ADS)

The creation of increasingly large multipartite entangled states is not only a fundamental scientific endeavour in itself, but is also the enabling technology for quantum information. Tremendous experimental effort has been devoted to generating multiparticle entanglement with a growing number of qubits. So far, up to six spatially separated single photons have been entangled based on parametric downconversion. Multiple degrees of freedom of a single photon have been exploited to generate forms of hyper-entangled states. Here, using new ultra-bright sources of entangled photon pairs, an eight-photon interferometer and post-selection detection, we demonstrate for the first time the creation of an eight-photon Schrödinger cat state with genuine multipartite entanglement. The ability to control eight individual photons represents a step towards optical quantum computation, and will enable new experiments on, for example, quantum simulation, topological error correction and testing entanglement dynamics under decoherence.

Yao, Xing-Can; Wang, Tian-Xiong; Xu, Ping; Lu, He; Pan, Ge-Sheng; Bao, Xiao-Hui; Peng, Cheng-Zhi; Lu, Chao-Yang; Chen, Yu-Ao; Pan, Jian-Wei

2012-04-01

343

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

344

Photon Factory activity report, 1989.  

National Technical Information Service (NTIS)

At the Photon Factory about 500 experiments are now running annually with about 50 experimental stations, the total operation time of the 2.5 GeV storage ring was 3400 hour in 1989, and the number of users was more than 2000, including 300 scientists from...

1990-01-01

345

Quantum Imaging with Incoherent Photons  

Microsoft Academic Search

We propose a technique to obtain subwavelength resolution in quantum imaging with potentially 100% contrast using incoherent light. Our method requires neither path-entangled number states nor multiphoton absorption. The scheme makes use of N photons spontaneously emitted by N atoms and registered by N detectors. It is shown that for coincident detection at particular detector positions a resolution of lambda\\/N

C. Thiel; T. Bastin; J. Martin; E. Solano; J. von Zanthier; G. S. Agarwal

2007-01-01

346

Photon-Photon Interactions via Rydberg Blockade  

SciTech Connect

We develop the theory of light propagation under the conditions of electromagnetically induced transparency in systems involving strongly interacting Rydberg states. Taking into account the quantum nature and the spatial propagation of light, we analyze interactions involving few-photon pulses. We show that this system can be used for the generation of nonclassical states of light including trains of single photons with an avoided volume between them, for implementing photon-photon gates, as well as for studying many-body phenomena with strongly correlated photons.

Gorshkov, Alexey V. [Institute for Quantum Information, California Institute of Technology, Pasadena, California 91125 (United States); Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106 (United States); Otterbach, Johannes [Department of Physics and Research Center OPTIMAS, Technische Universitaet Kaiserslautern, 67663, Kaiserslautern (Germany); Fleischhauer, Michael [Department of Physics and Research Center OPTIMAS, Technische Universitaet Kaiserslautern, 67663, Kaiserslautern (Germany); Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106 (United States); Pohl, Thomas [Max Planck Institute for the Physics of Complex Systems, 01187 Dresden (Germany); Lukin, Mikhail D. [Physics Department, Harvard University, Cambridge, Massachusetts 02138 (United States); Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106 (United States)

2011-09-23

347

Filtered statistics  

Microsoft Academic Search

Column statistics are an important element of cardinality estimation frameworks. More accurate estimates allow the optimizer of a RDBMS to generate better plans and improve the overall system's efficiency. This paper introduces filtered statistics, which model value distribution over a set of rows restricted by a predicate. This feature, available in Microsoft SQL Server, can be used to handle column

Pawel Terlecki; Hardik Bati; César A. Galindo-legaria; Peter Zabback

2009-01-01

348

BAYESIAN STATISTICS  

Microsoft Academic Search

Mathematical statistics uses two major paradigms, conventional (or frequentist), and Bayesian. Bayesian methods provide a complete paradigm for both statistical inference and decision mak- ing under uncertainty. Bayesian methods may be derived from an axiomatic system, and hence provide a general, coherentmethodology. Bayesian methods contain as particular cases many of the more often used frequentist procedures, solve many of the

José M. Bernardo

349

Descriptive statistics  

Microsoft Academic Search

Statistics is a science that provides precise techniques for collecting and sorting information made easy by tools and methods for further analysis.The object of descriptive statistics, from sample data, is to describe the most important characteristics, by which we refer to those amounts that provide information on the topic of interest which we are studying.

S. Pérez-Vicente; M. Expósito Ruiz

2009-01-01

350

Photonic metamaterials  

Microsoft Academic Search

The invention of metamaterials prompts reconsideratiou of a number of fundamental physical phenomena and enables a variety of unique properties and functionalities, These include negative refractive index, magnetism at optical frequencies, sub-wavelength resolution, \\

N. M. Litchinitser; V. M. Shalaev

2008-01-01

351

Number Factory  

NSDL National Science Digital Library

This interactive game develops fluency and flexibility with whole number operations. In each round the player is given 4 single-digit whole numbers, presented in the context of a factory. The player uses each number exactly once with the interactive calculator to arrive as close as possible to a given target number.

Doorman, Michiel

2003-01-01

352

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

353

Photon wave function  

Microsoft Academic Search

Photon wave function is a controversial concept. Controversies stem from the fact that photon wave functions can not have all the properties of the Schroedinger wave functions of nonrelativistic wave mechanics. Insistence on those properties that, owing to peculiarities of photon dynamics, cannot be rendered, led some physicists to the extreme opinion that the photon wave function does not exist.

Iwo Bialynicki-Birula

2005-01-01

354

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

355

Supernova brightening from chameleon-photon mixing  

SciTech Connect

Measurements of standard candles and measurements of standard rulers give an inconsistent picture of the history of the universe. This discrepancy can be explained if photon number is not conserved as computations of the luminosity distance must be modified. I show that photon number is not conserved when photons mix with chameleons in the presence of a magnetic field. The strong magnetic fields in a supernova mean that the probability of a photon converting into a chameleon in the interior of the supernova is high, this results in a large flux of chameleons at the surface of the supernova. Chameleons and photons also mix as a result of the intergalactic magnetic field. These two effects combined cause the image of the supernova to be brightened resulting in a model which fits both observations of standard candles and observations of standard rulers.

Burrage, C. [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, Cambridge, CB2 0WA (United Kingdom)

2008-02-15

356

Number Sense  

NSDL National Science Digital Library

In this online math game from Cyberchase, learners play against Hacker in a place value game. The goal is to make a number bigger than the one created by Hacker's number machine. Learners select the numbers in the order in which they want them to go into their machine. The challenge is to either make a number larger than the one on Hacker's machine or realize that it's impossible to make a number bigger than Hacker's, no matter what the combination.

Wnet.org

2011-01-01

357

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

358

Entangled-photons Raman spectroscopy  

NASA Astrophysics Data System (ADS)

It is well known that Raman spectroscopy suers from low signal-to-noise ratio (SNR). In this paper we oer a general framework based on quantum illumination that describes Rayleigh and Raman spectroscopy using an arbitrarily large number of entangled and non-entangled photons. Our objective is to analyze Rayleigh and Raman spectroscopy as a quantum information channel and study its asymptotic limits. In particular, if we consider quantum entanglement as an information resource, then the use of entangled photons oers an exponentially large improvement on the SNR of the Raman spectrometer. That is, the correlations embedded in quantum entanglement can be exploited to enhance the Raman signature of tested samples.

Lanzagorta, Marco

2012-05-01

359

Computational Modeling of Photonic Crystal Microcavity Single-Photon Emitters  

NASA Astrophysics Data System (ADS)

Conventional cryptography is based on algorithms that are mathematically complex and difficult to solve, such as factoring large numbers. The advent of a quantum computer would render these schemes useless. As scientists work to develop a quantum computer, cryptographers are developing new schemes for unconditionally secure cryptography. Quantum key distribution has emerged as one of the potential replacements of classical cryptography. It relics on the fact that measurement of a quantum bit changes the state of the bit and undetected eavesdropping is impossible. Single polarized photons can be used as the quantum bits, such that a quantum system would in some ways mirror the classical communication scheme. The quantum key distribution system would include components that create, transmit and detect single polarized photons. The focus of this work is on the development of an efficient single-photon source. This source is comprised of a single quantum dot inside of a photonic crystal microcavity. To better understand the physics behind the device, a computational model is developed. The model uses Finite-Difference Time-Domain methods to analyze the electromagnetic field distribution in photonic crystal microcavities. It uses an 8-band k · p perturbation theory to compute the energy band structure of the epitaxially grown quantum dots. We discuss a method that combines the results of these two calculations for determining the spontaneous emission lifetime of a quantum dot in bulk material or in a microcavity. The computational models developed in this thesis are used to identify and characterize microcavities for potential use in a single-photon source. The computational tools developed are also used to investigate novel photonic crystal microcavities that incorporate 1D distributed Bragg reflectors for vertical confinement. It is found that the spontaneous emission enhancement in the quasi-3D cavities can be significantly greater than in traditional suspended slab cavities.

Saulnier, Nicole A.

360

Physics of photons. III  

NASA Astrophysics Data System (ADS)

Wave equations are proposed for the photon which take the feasibility of a photon rest mass into account. It is shown that massless photons are asymmetrical in spin; massive photons which have “mirror” symmetry and exhibit the speed of light in a vacuum can be localized in either region. The solution is presented for the problem of the behavior of photons in a central field and the energy of coupled states is found.

Karpenko, I. K.

1990-06-01

361

Vital and Health Statistics, Series 2, Number 143. Assessing the Potential of National Strategies for Electronic Health Records for Population Health Monitoring and Research. Data Evaluation and Methods Research.  

National Technical Information Service (NTIS)

The Centers for Disease Control and Preventions National Center for Health Statistics commissioned this report to assess the potential contribution of national strategies for electronic health records to population health monitoring and research. The repo...

2006-01-01

362

Vital and Health Statisties, Series 10, Number 220. Summary Health Statistics for the U.S. Population: National Health Interview Survey, 2002. Data from the National Health Interview Survey.  

National Technical Information Service (NTIS)

The report presents both age-adjusted and unadjusted health statistics from the 2002 National Health Interview Survey (NHIS) for the civilian noninstitutionalized population of the United States, classified by age, sex, race and Hispanic or Latino origin,...

2004-01-01

363

Photon-Photon Collisions -- Past and Future  

SciTech Connect

I give a brief review of the history of photon-photon physics and a survey of its potential at future electron-positron colliders. Exclusive hadron production processes in photon-photon and electron-photon collisions provide important tests of QCD at the amplitude level, particularly as measures of hadron distribution amplitudes. There are also important high energy {gamma}{gamma} and e{gamma} tests of quantum chromodynamics, including the production of jets in photon-photon collisions, deeply virtual Compton scattering on a photon target, and leading-twist single-spin asymmetries for a photon polarized normal to a production plane. Since photons couple directly to all fundamental fields carrying the electromagnetic current including leptons, quarks, W's and supersymmetric particles, high energy {gamma}{gamma} collisions will provide a comprehensive laboratory for Higgs production and exploring virtually every aspect of the Standard Model and its extensions. High energy back-scattered laser beams will thus greatly extend the range of physics of the International Linear Collider.

Brodsky, Stanley J.; /SLAC

2005-12-02

364

Photon emitting, absorption, and reconstruction of photons  

NASA Astrophysics Data System (ADS)

Photon cannot keep itself unchanged from emission to absorption. The information encoded on the photon is also changed due to interaction with environment. There has no definitely demonstration that the photon being absorbed is the original one from ideal light source since the quantum mechanics itself is an indeterminate theory that the physical measurement is only the probability. We divide the change of the photon state into two parts that one can be compensated and the other cannot be compensated. A concept of photon reconstruction is introduced to explain every optical phenomena including Raman scattering, multi-photon absorption, nonlinear phenomena, free electron lasing, quantum entanglement, high order coherence, ghost imaging and the de-phase which result in error bits or information loss in the quantum information process. An experimental result is explained to show that the signal photon can modify the background even the energy of the photon is not enough for absorption in the wide-band gap semiconductor material. The photon-current-voltage curve and dark-current-voltage curve of an absorption, grating, and multiplication InGaAs/InP avalanche photodiode is analyzed to show that 1550nm input light modified the dark background even the applied reverse bias voltage is far below the punch-through voltage. This increase of the dark count directly relates to the input photons at the 1550nm wavelength but is not due to absorption in the absorption layer and insensitive to the applied voltage.

Liao, Changjun; Wang, Jindong; Wei, Zhengjun; Guo, Jianping

2007-01-01

365

A Statistic on Involutions  

Microsoft Academic Search

We define a statistic, called weight, on involutions and consider two applications in which this statistic arises. Let I(n) denote the set of all involutions on [n](={1,2,..., n}) and let F(2n) denote the set of all fixed point free involutions on [2n]. For an involution ?, let |?| denote the number of 2-cycles in ?. Let[ n]q=1+q+?+qn-1 and let \\u000a

Rajendra S. Deodhar; Murali K. Srinivasan

2001-01-01

366

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

367

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

368

The study of single photon detector for quantum key distribution  

NASA Astrophysics Data System (ADS)

This paper introduces the design of a single photon detector based on the AT89C51 single chip microcontroller for quantum key distribution at telecommunication wavelengths. An avalanche photodiode (APD) is operated in Geiger mode and stabilized at temperature of 228K for translating the single photon signals into electrical pulses. The photon induced avalanche pulses are amplified and converted to digital data. The microcontroller discriminates the data, counting the number of photons, and then displays the photon number and the detection efficiency on a LCD display. The instrument can effectively support the study of quantum key distribution.

Wei, Zhengjun; Wang, Jindong; Li, Kaizhen; Zhou, Peng; Liao, Changjun; Guo, Jianping; Liu, Songhao

2008-03-01

369

MRSA Statistics  

MedlinePLUS

... better recognize and prevent MRSA skin infections MRSA Statistics Reducing methicillin-resistant Staphylococcus aureus (MRSA) in both ... to MRSA, visit: CDC MRSA website CDC Active Bacterial Core Surveillance CDC Vital Signs Report National Healthcare ...

370

UCLA Statistics Series  

NSDL National Science Digital Library

The University of California Los Angeles Statistics Series presents a collection of more than 250 preprints covering a wide array of statistical topics, such as descriptive multivariate analysis, advanced linear models, survey construction and analysis, teaching statistics, and much more. The preprints are arranged by paper number only, hence users must browse the entire list to locate relevant items. Approximately half of the full-text preprints are accessible in HTML, .pdf, or postscript formats. To access preprints not available electronically, users must contact the authors of the papers; author addresses are provided.

371

NUMBER SENSE  

NSDL National Science Digital Library

Students will practice counting to 100, making numbers with base ten blocks and practicing ordinal numbers! Math is FUN! Lets have fun practicing counting to 100 ! Click when you are ready!Counting Now that you have practiced counting to 100, lets use the base ten blocks to make the number that is on the screen. Click when you are ready!Working with Base Ten Blocks We have now practiced counting and making numbers, lets ...

Simpson, Ms.

2007-10-27

372

Controlled generation of four-photon polarization-entangled decoherence-free states with conventional photon detectors  

SciTech Connect

We propose a protocol for the controlled generation of four-photon polarization-entangled decoherence-free states with a certain success probability. The proposed setup involves simple linear optical elements, two single-photon polarzaition entangled states, a pair of two-photon polarization entangled states, and conventional photon detectors that only distinguish the vacuum and nonvacuum Fock number states. This makes the protocol more realizable in experiments.

Xia Yan [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Department of Physics, College of Science, Yanbian University, Yanji, Jilin 133002 (China); Song Jie; Song Heshan [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Zhang Shou [Department of Physics, College of Science, Yanbian University, Yanji, Jilin 133002 (China)

2009-01-15

373

Leftist Numbers  

ERIC Educational Resources Information Center

|The leftist number system consists of numbers with decimal digits arranged in strings to the left, instead of to the right. This system fails to be a field only because it contains zerodivisors. The same construction with prime base yields the p-adic numbers.|

Rich, Andrew

2008-01-01

374

Number Time  

ERIC Educational Resources Information Center

|This article features Number Time, a site developed by the British Broadcasting Corporation (BBC) for young mathematics learners, located at www.bbc.co.uk/schools/numbertime. The site uses interactive animation to help children in pre-K through grade 2 understand and practice number basics. Users will find online games, videos that tell number

Herrera, Terese A.

2004-01-01

375

Number theory  

Microsoft Academic Search

Number theory, an abstract branch of mathematics that deals with relationships between whole numbers, has provided highly useful answers to numerous real-world problems. The author briefly reviews earlier uses of number theory and then examines recent applications to music, cryptography, and error-correction codes

M. R. Schroeder

1989-01-01

376

Number Factory  

NSDL National Science Digital Library

This interactive Java applet promotes number sense, estimation, and provides practice with order of operations. The player's goal is to make a numerical expression using the four given numbers and the four basic operations with the result being the target number (or as close as they can get to it). The student can also use brackets in their calculation.

Doorman, Michiel

2012-01-07

377

Nuclear photonics  

NASA Astrophysics Data System (ADS)

With the planned new ?-beam facilities like MEGa-ray at LLNL (USA) or ELI-NP at Bucharest (Romania) with 1013 ?/s and a band width of ?E?/E?~10-3, a new era of ? beams with energies up to 20MeV comes into operation, compared to the present world-leading HI?S facility at Duke University (USA) with 108 ?/s and ?E?/E?~3.10-2. In the long run even a seeded quantum FEL for ? beams may become possible, with much higher brilliance and spectral flux. At the same time new exciting possibilities open up for focused ? beams. Here we describe a new experiment at the ? beam of the ILL reactor (Grenoble, France), where we observed for the first time that the index of refraction for ? beams is determined by virtual pair creation. Using a combination of refractive and reflective optics, efficient monochromators for ? beams are being developed. Thus, we have to optimize the total system: the ?-beam facility, the ?-beam optics and ? detectors. We can trade ? intensity for band width, going down to ?E?/E?~10-6 and address individual nuclear levels. The term "nuclear photonics" stresses the importance of nuclear applications. We can address with ?-beams individual nuclear isotopes and not just elements like with X-ray beams. Compared to X rays, ? beams can penetrate much deeper into big samples like radioactive waste barrels, motors or batteries. We can perform tomography and microscopy studies by focusing down to ?m resolution using Nuclear Resonance Fluorescence (NRF) for detection with eV resolution and high spatial resolution at the same time. We discuss the dominating M1 and E1 excitations like the scissors mode, two-phonon quadrupole octupole excitations, pygmy dipole excitations or giant dipole excitations under the new facet of applications. We find many new applications in biomedicine, green energy, radioactive waste management or homeland security. Also more brilliant secondary beams of neutrons and positrons can be produced.

Habs, D.; Günther, M. M.; Jentschel, M.; Thirolf, P. G.

2012-07-01

378

Nuclear photonics  

SciTech Connect

With the planned new {gamma}-beam facilities like MEGa-ray at LLNL (USA) or ELI-NP at Bucharest (Romania) with 10{sup 13}{gamma}/s and a band width of {Delta}E{gamma}/E{gamma} Almost-Equal-To 10{sup -3}, a new era of {gamma} beams with energies up to 20MeV comes into operation, compared to the present world-leading HI{gamma}S facility at Duke University (USA) with 10{sup 8}{gamma}/s and {Delta}E{gamma}/E{gamma} Almost-Equal-To 3 Dot-Operator 10{sup -2}. In the long run even a seeded quantum FEL for {gamma} beams may become possible, with much higher brilliance and spectral flux. At the same time new exciting possibilities open up for focused {gamma} beams. Here we describe a new experiment at the {gamma} beam of the ILL reactor (Grenoble, France), where we observed for the first time that the index of refraction for {gamma} beams is determined by virtual pair creation. Using a combination of refractive and reflective optics, efficient monochromators for {gamma} beams are being developed. Thus, we have to optimize the total system: the {gamma}-beam facility, the {gamma}-beam optics and {gamma} detectors. We can trade {gamma} intensity for band width, going down to {Delta}E{gamma}/E{gamma} Almost-Equal-To 10{sup -6} and address individual nuclear levels. The term 'nuclear photonics' stresses the importance of nuclear applications. We can address with {gamma}-beams individual nuclear isotopes and not just elements like with X-ray beams. Compared to X rays, {gamma} beams can penetrate much deeper into big samples like radioactive waste barrels, motors or batteries. We can perform tomography and microscopy studies by focusing down to {mu}m resolution using Nuclear Resonance Fluorescence (NRF) for detection with eV resolution and high spatial resolution at the same time. We discuss the dominating M1 and E1 excitations like the scissors mode, two-phonon quadrupole octupole excitations, pygmy dipole excitations or giant dipole excitations under the new facet of applications. We find many new applications in biomedicine, green energy, radioactive waste management or homeland security. Also more brilliant secondary beams of neutrons and positrons can be produced.

Habs, D.; Guenther, M. M.; Jentschel, M.; Thirolf, P. G. [Ludwig-Maximilians-Universitaet Muenchen, D-85748 Garching (Germany); Max Planck Institut fuer Quantenoptik, D-85748 Garching (Germany); Institut Laue-Langevin, F-38042 Grenoble (Germany); Ludwig-Maximilians-Universitaet Muenchen, D-85748 Garching (Germany)

2012-07-09

379

Superharmonic numbers  

NASA Astrophysics Data System (ADS)

Let tau(n) denote the number of positive divisors of a natural number n>1 and let sigma(n) denote their sum. Then n is superharmonic if sigma(n)mid n^ktau(n) for some positive integer k . We deduce numerous properties of superharmonic numbers and show in particular that the set of all superharmonic numbers is the first nontrivial example that has been given of an infinite set that contains all perfect numbers but for which it is difficult to determine whether there is an odd member.

Cohen, Graeme L.

2009-03-01

380

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

381

Bose-Einstein condensation of photons in a 'whitewall' photon box  

Microsoft Academic Search

Bose-Einstein condensation, the macroscopic ground state occupation of a system of bosonic particles below a critical temperature, has been observed in cold atomic gases and solid-state physics quasiparticles. In contrast, photons do not show this phase transition usually, because in Planck's blackbody radiation the particle number is not conserved and at low temperature the photons disappear in the walls of

Jan Klärs; Julian Schmitt; Frank Vewinger; Martin Weitz

2011-01-01

382

A position-sensitive superheated emulsion chamber for three-dimensional photon dosimetry.  

PubMed

A position-sensitive detector chamber is introduced for the three-dimensional (3D) dosimetry of photon-emitting brachytherapy sources. The detector is based on an extremely fine suspension of monochloropentafluoroethane droplets emulsified in a gel. The droplets are highly superheated at room temperature and their evaporation can be triggered by photon interactions, leading to the formation of microscopic bubbles. Thus, when photon-emitting brachytherapy sources are inserted into the detector, bubble distributions form around them, enabling visualization of the radiation field. The tissue-equivalent emulsifier gel is highly viscous and keeps the bubbles immobilized at the location of their formation. Bubbles can then be imaged by nuclear magnetic resonance or optical scanning techniques. After the imaging, the detector can be pressurized in order to recondense the bubbles to the liquid phase. In a few minutes, the device is annealed and ready to be used again for repeated measurements improving the counting statistics. The photon sensitivity of the monochloropentafluoroethane droplets was determined with highly filtered, quasi-monochromatic x-ray beams and radionuclide gamma sources. The air-kerma response presents a broad maximum at low energies, due to the relatively high effective atomic number of the halocarbon molecule. A prototype chamber was built and successfully tested: bubble distributions deriving from the insertion of a 125I source were imaged by means of a slice-selective 3D gradient-echo technique. These experiments confirm the potential and viability of this new approach to 3D photon dosimetry. PMID:9623646

d'Errico, F; Nath, R; Lamba, M; Holland, S K

1998-05-01

383

Lyapunov exponents for one-dimensional aperiodic photonic bandgap structures  

NASA Astrophysics Data System (ADS)

Existing in the "gray area" between perfectly periodic and purely randomized photonic bandgap structures are the socalled aperoidic structures whose layers are chosen according to some deterministic rule. We consider here a onedimensional photonic bandgap structure, a quarter-wave stack, with the layer thickness of one of the bilayers subject to being either thin or thick according to five deterministic sequence rules and binary random selection. To produce these aperiodic structures we examine the following sequences: Fibonacci, Thue-Morse, Period doubling, Rudin-Shapiro, as well as the triadic Cantor sequence. We model these structures numerically with a long chain (approximately 5,000,000) of transfer matrices, and then use the reliable algorithm of Wolf to calculate the (upper) Lyapunov exponent for the long product of matrices. The Lyapunov exponent is the statistically well-behaved variable used to characterize the Anderson localization effect (exponential confinement) when the layers are randomized, so its calculation allows us to more precisely compare the purely randomized structure with its aperiodic counterparts. It is found that the aperiodic photonic systems show much fine structure in their Lyapunov exponents as a function of frequency, and, in a number of cases, the exponents are quite obviously fractal.

Kissel, Glen J.

2011-09-01

384

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

385

Quantum phase transition of light in a one-dimensional photon-hopping-controllable resonator array  

SciTech Connect

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 Chunwang; Gao Ming; Deng Zhijiao; Dai Hongyi; Chen Pingxing; Li Chengzu [College of Science, National University of Defense Technology, Changsha 410073 (China)

2011-10-15

386

Statistical interpolation of FET data base measurements  

Microsoft Academic Search

Research into valid and compact statistical FET models is described. A statistical interpolation technique that extends the truth model proposed by J. Purviance et al. (1990) is presented. The truth model simply uses samples from a FET measurement database when performing statistical analysis and design of circuits. The statistical interpolation technique presented multiplies the number of points within a statistical

Lowell Campbell; John Purviance; C. Potratz

1991-01-01

387

Statistical optics  

NASA Astrophysics Data System (ADS)

This book is based on the thesis that some training in the area of statistical optics should be included as a standard part of any advanced optics curriculum. Random variables are discussed, taking into account definitions of probability and random variables, distribution functions and density functions, an extension to two or more random variables, statistical averages, transformations of random variables, sums of real random variables, Gaussian random variables, complex-valued random variables, and random phasor sums. Other subjects examined are related to random processes, some first-order properties of light waves, the coherence of optical waves, some problems involving high-order coherence, effects of partial coherence on imaging systems, imaging in the presence of randomly inhomogeneous media, and fundamental limits in photoelectric detection of light. Attention is given to deterministic versus statistical phenomena and models, the Fourier transform, and the fourth-order moment of the spectrum of a detected speckle image.

Goodman, J. W.

388

Number Patterns  

NSDL National Science Digital Library

This Java applet allows users to practice recognizing patterns with integers and completing a sequence of numbers by adding or subtracting a common difference. The user is given the first five terms of a number pattern and asked to complete the pattern with the next two numbers. There is a check answer button for feedback and a new pattern button for additional practice. Instructions for users and teacher information are available through links at the top of the page.

2005-09-30

389

Number Grid  

NSDL National Science Digital Library

With this interactive Flash applet, intended for use with a projector or interactive white board, teachers can help students understand place value and the structure of our number system. Shapes can be placed on the 100 chart; students use number patterns to determine which numbers are hidden under the shapes. By choosing Hide or Highlight and then selecting specific rows or columns to hide or highlight, the teacher can adjust the challenge level or bring attention to parts of the chart.

2012-01-01

390

Number Cruncher  

NSDL National Science Digital Library

In this online puzzle game, learners need to choose a path from a starting number to a goal number. Along the path are simple operations (e.g. add 1, subtract 2, multiply by 2) to change the current number to a new number. This is a good challenge for young learners. When learners set up a free account at Kinetic City, they can answer bonus questions at the end of the activity as a quick assessment. As a larger assessment, learners can complete the Bug Blaster game after they've completed several activities.

Science, American A.

2009-01-01

391

Prompt Photon Production and Photon–Jet–Hadron Correlations in PHENIX  

NASA Astrophysics Data System (ADS)

A variety of heavy-ion data from RHIC and recently also from the LHC on hard direct photon production testifies that this non-interacting probe of the densely colored QGP continues to lend new insights to understanding jet suppression and energy loss. In this talk, we report on new results of high pT single direct photon production in both p + p and Heavy Ion systems. Additionally, new PHENIX results on fragmentation functions of the direct photon–jet photon–hadron correlations from the 2010 dataset, when combined with the previous 2007 dataset result, now show an enhancement that is statistically significant in regions of low z. It is found that this enhancement appears to occur over relatively wide angles from back-to-back with respect to the direct photon trigger.

Frantz, Justin

2013-05-01

392

Total-Absorption Scintillation Counter for High-Energy Photons  

Microsoft Academic Search

A total-absorption scintillation counter for high-energy photons is ; developed with plus or minus % energy spread for 130-Mev photons. The counter ; is built of enough plastic scintillator to contain most of the energy and ; maintain a high detection efficiency. The technique of observing a statistical ; sampling of light from an integrating volume is used. The integrating

William C. Bowman; Jim B. Carroll; John A. Poirier

1962-01-01

393

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

394

The Net by Numbers.  

ERIC Educational Resources Information Center

The expansion of the commercial Internet has encouraged the interpretation of the Internet and its uses as a potential marketing medium. Examines statistical and demographic information about the Internet including number of Internet hosts and World Wide Web servers, and estimates of Internet users; and raises questions about definitions and…

McMurdo, George

1996-01-01

395

Photonic Acceleration in Astrophysics  

NASA Astrophysics Data System (ADS)

Gamma Ray Bursts (GRB) deliver very high intensity photons with energies from 10 keV to over 100 MeV at a irradiance of 10^30 (30 km/R)^2 Watt/cm^2. This is in the nonlinear QED regime and the induced wakefield is close to the Schwinger field (E ~^16 V/cm). Protons and electrons can be accelerated in such a strong field to 10^21 eV/km in the vicinity of the GRB source. The maximum acceleration is limited by the critical Schwinger field times the length of the field: q ( E (= 10^16.5 V/cm) ( L ((1000 km) = 10^24 eV. Trains of such wakefields are expected in the outflow of photons from GRB's, which gives a Chapman-Kolmogorov type power energy spectrum [Chandrasekhar, 1953; Mima et al. 1991], which is close to a Bremsstrahlung-type spectrum, f(E) = E^-a (a = 1). Some of the accelerated protons can have energies as high as 10^23 eV. The secondary pions and their daughters (neutrinos) that may be produced in-situ near the acceleration site of the GRB can have energies around 10^22 eV (= 1.6 ( 10^10 erg). The neutrino flux from the semi-daily occurrence of GRB's (with energy output of ~ 10^52 erg can provide a flux of high intensity EHE neutrinos in the universe as a function of the acceleration efficiency coefficient (k): I( (E ( 10^21 eV) = 5k (10^52 eV)/(1.6 ( 10^10 erg)/4(pi)R^2/day = 1 /km^2 yr (for k = 1% *). *(cf. Laser wakefield experiments with Petawatt indicated k = 5 ~ 10% for protons [M. Key, 1999].) A compact photonic acceleration mechanism is thus suggested as a candidate for the origin of extremely high energy cosmic rays (EECR). Observed characteristics of EECR beyond energies of several 1019 eV pose a number of challenges and opportunities for physics and astrophysics. Foremost among them is the apparent defiance or violation of the proton energy cutoff of Greisen-Zatsepin-Kuzmin (GZK). The other is the apparent correlation in some of ECR events. And the most important is the difficulty to accelerate particles by the conventional Fermi mechanism to reach such high energies. We suggest that the intense photon flux emanating from a gamma ray burst is capable of yielding a sufficiently robust and rugged plasma structure suitable to accelerate protons and other charged particles to extreme high energies ( ~ 10^22 eV) over thousands of kilometers in the GRB atmosphere. Photon flux above a certain threshold can self-modulate in the plasma to create longitudinal (as well as transverse) structures that help snowplow and accelerate charged particles. The sustained large flux of photons maintains the acceleration by successive flux to repeat the process once a particular class of photons give up energies to particles and red-shift. The decrease of plasma density away from the GRB further facilitates this process, providing ever greater coherence (acceleration) length. The stochastic repetition of this process yields a power-law energy spectrum with an exponent of -1. Such compact prompt intense acceleration of protons in the vicinity of GRB manifests through neutrinos (by proton-proton or proton-photon collisions near GRB). These neutrinos can propagate over a cosmological distance without decay or loss until reaching and colliding with relic neutrinos in our Super-Cluster (Virgo), eventually converting themselves into EECR particles such as protons and photons of energies of ~ 10^20 eV. The estimated neutrino energy flux and spectrum are consistent with observation and have a number of implications on EHECR, cosmological origin, and neutrino physics. Other high field astronomical sites such as the core and jets of Active Galactic Nuclei can have lesser but similar accelerations.

Takahashi, Yoshiyuki

2000-04-01

396

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

397

``Applied Statistics''  

Microsoft Academic Search

IN his review of my book ``Statistical Methods in Electrical Engineering'' (Nature, March 19, p. 484), Mr. F. Downton criticizes my statement that Bayes' theorem is controversial. The heading of the paragraph in Sir Ronald Fisher's book which I cited is ``The Rejection of Inverse Probability''. Coupled with the lack of mention of Bayes beyond the introductory chapter, I can

D. A. Bell

1955-01-01

398

Statistical Issues  

Microsoft Academic Search

The present document sumarizes the methodology utilized by the UNESCO Division of Statistics in the 1994 assessment of estimates and projections of adult illiteracy by country in the world, Section I of this document provides an overview of the background and rationale behind the recent 1994 assessment, and the policy and monitoring relevance of literacy as a key indicator of

K. J. Holzinger

1924-01-01

399

Statistical Engineering  

NSDL National Science Digital Library

A good resource for problems in statistics in engineering. Contains some applets, and good textual examples related to engineering. Some topics include Monte Carlo method, Central Limit Theorem, Risk, Logistic Regression, Generalized Linear Models, and Confidence. Overall, this is a well presented and good site for anyone interested in engineering or mathematics.

Annis, Charles

2008-12-30

400

Sub-Poissonian Statistics of Rydberg-Interacting Dark-State Polaritons  

NASA Astrophysics Data System (ADS)

We observe individual dark-state polaritons as they propagate through an ultracold atomic gas involving Rydberg states coupled via an electromagnetically induced transparency resonance. Strong long-range interactions between Rydberg excitations give rise to a blockade between polaritons, resulting in large optical nonlinearities and modified polariton number statistics. By combining optical imaging and high-fidelity detection of the Rydberg polaritons we investigate both aspects of this coupled atom-light system. We map out the full nonlinear optical response as a function of atomic density and follow the temporal evolution of polaritons through the atomic cloud. In the blockade regime, the statistical fluctuations of the polariton number drop well below the quantum noise limit. The low level of fluctuations indicates that photon correlations modified by the strong interactions have a significant backaction on the Rydberg atom statistics.

Hofmann, C. S.; Günter, G.; Schempp, H.; Robert-de-Saint-Vincent, M.; Gärttner, M.; Evers, J.; Whitlock, S.; Weidemüller, M.

2013-05-01

401

Photon-photon scattering of gamma rays at cosmological distances  

Microsoft Academic Search

The total scattering rate, the optical depth of the universe, and the scattered photon spectrum are derived from gamma-ray photons scattering in an isotropic field of blackbody photons. By solving the kinetic equation describing repeated photon-photon scattering for both monoenergetic and power-law injection of photons, it is shown how the photon spectra resulting from pair-photon cascades are further reprocessed by

Roland Svensson; Andrzej Zdziarski

1990-01-01

402

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;…

Lynch, Mary Jo; Oder, Norman; Halstead, Kent; Fox, Bette-Lee

2003-01-01

403

Photonic crystal pioneer  

NASA Astrophysics Data System (ADS)

Over the past ten years, Crystal Fiber, now part of NKT Photonics, has been busy commercializing photonic crystal fibre. Nadya Anscombe finds out about the evolution of the technology and its applications.

Anscombe, Nadya

2011-08-01

404

Total Photon Absorption.  

National Technical Information Service (NTIS)

The present discussion is limited to a presentation of the most recent total photonuclear absorption experiments performed with real photons at intermediate energy, and more precisely in the region of nucleon resonances. The main sources of real photons a...

P. Carlos

1985-01-01

405

Boston University Photonics Center.  

National Technical Information Service (NTIS)

The Boston University Photonics Center was established to conduct basic and applied research on photonics materials, devices, and systems related to defense needs, and to establish research laboratories and facilities to support collaboration among academ...

P. Blasche

1998-01-01

406

Photonic crystal and photonic wire device structures  

NASA Astrophysics Data System (ADS)

Photonic devices that exploit photonic crystal (PhC) principles in a planar environment continue to provide a fertile field of research. 2D PhC based channel waveguides can provide both strong confinement and controlled dispersion behaviour. In conjunction with, for instance, various electro-optic, thermo-optic and other effects, a range of device functionality is accessible in very compact PhC channel-guide devices that offer the potential for high-density integration. Low enough propagation losses are now being obtained with photonic crystal channel-guide structures that their use in real applications has become plausible. Photonic wires (PhWs) can also provide strong confinement and low propagation losses. Bragg-gratings imposed on photonic wires can provide dispersion and frequency selection in device structures that are intrinsically simpler than 2D PhC channel guides--and can compete with them under realistic conditions.

De La Rue, Richard; Sorel, Marc; Johnson, Nigel; Rahman, Faiz; Ironside, Charles; Cronin, Lee; Watson, Ian; Martin, Robert; Jin, Chongjun; Pottier, Pierre; Chong, Harold; Gnan, Marco; Jugessur, Aju; Camargo, Edilson; Erwin, Grant; Md Zain, Ahmad; Ntakis, Iraklis; Hobbs, Lois; Zhang, Hua; Armenise, Mario; Ciminelli, Caterina; Coquillat, Dominique

2005-09-01

407

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)

408

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.

409

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

410

Statistics of stable marriages  

NASA Astrophysics Data System (ADS)

In the stable marriage problem N men and N women have to be matched by pairs under the constraint that the resulting matching is stable. We study the statistical properties of stable matchings in the large N limit using both numerical and analytical methods. Generalizations of the model including singles and unequal numbers of men and women are also investigated.

Dzierzawa, M.; Omero, M.-J.

2000-11-01

411

Fur Statistics, 2008.  

National Technical Information Service (NTIS)

Statistics Canada has collected information on the inventory of ranch raised fox and mink and the number and value of pelts taken for both ranch raised and wild pelts since 1919. Data on wildlife furs are on a 'fur year basis' which is from July 1 to June...

2009-01-01

412

Plasma photonic crystal  

Microsoft Academic Search

Plasma photonic crystals are presented in this paper. A plasma photonic crystal can control the propagation of electromagnetic\\u000a waves. Similar to other photonic crystals, the permittivity of a plasma photonic crystal is distributed as periodic arrays.\\u000a The properties of periodic arrays of plasma can broaden the range of frequency and enhance the efficiency of beam-wave interaction.\\u000a In special uses, the

Wei Li; Yong Zhao; Ruizhen Cui; Haitao Zhang

2009-01-01

413

Membrane photon sieve telescope  

NASA Astrophysics Data System (ADS)

We have developed diffractive primaries in flat membranes for space-based imagery. They are an attractive approach in that they are much simple to fabricate, launch and deploy compared to conventional three-dimensional optical structures. In this talk we highlight the design of a photon sieve which consists of a large number of holes in an otherwise opaque substrate. We present both theoretical and experimental results from small-scale prototypes and key solutions to issues of limited bandwidth and efficiency that have been addressed. Our current efforts are being directed towards an on-orbit 0.2m solar observatory demonstration deployed from a 3U CubeSat bus.

Andersen, Geoff; Dearborn, Michael E.; McHarg, Matthew G.; Harvey, Jeff

2011-09-01

414

Photon wave mechanics  

Microsoft Academic Search

Coordinate-space photon wave functions and their quantum-mechanical wave equations are presented. We show that two-time, two-photon wave functions are equivalent to two-photon detection amplitudes of quantum optics. Analogy to second-order coherence tensors is made.

Brian J. Smith; M. G. Raymer

2006-01-01

415

The photon wave function  

Microsoft Academic Search

We review and sharpen the concept of a photon wave function based on the quantum theory of light. We argue that a point-like atom serves as the archetype for both the creation and detection of photons. Spontaneous emission from atoms provides a spatially localized source of photon states that serves as a natural wave packet basis for quantum states of

A. Muthukrishnan; M. O. Scully; M. S. Zubairy

2005-01-01

416

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

417

CT number definition  

NASA Astrophysics Data System (ADS)

The accuracy of CT number plots has been found lacking in several medical applications. This is of concern since the ability to compare and evaluate results on a reproducible and standard basis is essential to long term development. Apart from the technical limitations arising from the CT scanner and the data treatment, there are fundamental issues with the definition of the Hounsfield number, namely the absence of a standard photon energy and the need to specify the attenuation mechanism for standard measurements. This paper presents calculations to demonstrate the shortcomings of the present definition with a brief discussion. The remedy is straightforward, but probably of long duration as it would require an international agreement.

Bryant, J. A.; Drage, N. A.; Richmond, S.

2012-04-01

418

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

419

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. [USRA-RIACS, 444, Castro St, Suite 320, Mountain View, CA 94041 (United States); Cohen-Tanugi, Johann [SLAC/KIPAC, Stanford University, Stanford, CA (United States)

2007-07-12

420

Statistical microeconomics  

NASA Astrophysics Data System (ADS)

A statistical generalization is made of microeconomics in the spirit of going from classical to statistical mechanics. The price and quantity of every commodity1The term commodities is used for goods and services. traded in the market, at each instant of time, is considered to be an independent random variable: all prices and quantities are considered to be stochastic processes, with the observed market prices being a random sample of the stochastic prices. The dynamics of market prices is determined by an action functional and, for concreteness, a specific model is proposed. The model can be calibrated from the unequal time correlation of the market commodity prices. A perturbation expansion for the correlation functions is defined in powers of the inverse of the total budget of the aggregate consumer and the propagator for the market prices is evaluated.

Baaquie, Belal E.

2013-10-01

421

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

422

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

423

Number Patterns  

NSDL National Science Digital Library

Students are given a worksheet and asked to identify and extend the growing or repeating numerical patterns. Students develop their own number pattern and create a model showing the pattern and the next three stages of the pattern.

Cornwell, Susan

2010-07-22

424

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

425

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

426

Numerical characterization of nanopillar photonic crystal waveguides and directional couplers  

Microsoft Academic Search

We numerically characterize a novel type of a photonic crystal waveguide, which consists of several rows of periodically arranged dielectric cylinders. In such a nanopillar photonic crystal waveguide, light confinement is due to the total internal reflection. A nanopillar waveguide is a multimode waveguide, where the number of modes is equal to the number of rows building the waveguide. The

Dmitry N. Chigrin; Andrei V. Lavrinenko; Clivia M. Sotomayor Torres

2005-01-01

427

Hierarchy of feasible nonclassicality criteria for sources of photons  

NASA Astrophysics Data System (ADS)

We present an ab-initio derivation of a hierarchy of efficient nonclassicality criteria for sources of photons. The operational criteria are explicitly proposed for the linear optical multiport and feasible multiplexed single-photon detectors. The lowest criterion is equivalent to the frequently used g(2)(0) autocorrelation measurement testing the anticorrelation effect of photons. We also derive a hierarchy of criteria for the detectors capable to at least partially estimate photon-number distribution. We prove the usefulness of both hierarchies to detect the nonclassical states from the noisy multimode single-photon sources and the nonclassical states from the multiphoton sources.

Filip, Radim; Lachman, Lukáš

2013-10-01

428

Photonic realization of the quantum Rabi model.  

PubMed

We realize a photonic analog simulator of the quantum Rabi model, based on light transport in femtosecond-laser-written waveguide superlattices, which provides an experimentally accessible test bed to explore the physics of light-matter interaction in the deep strong coupling regime. Our optical setting enables us to visualize dynamical regimes not yet accessible in cavity or circuit quantum electrodynamics, such as the bouncing of photon number wave packets in parity chains of Hilbert space. PMID:22680717

Crespi, A; Longhi, S; Osellame, R

2012-04-19

429

Photon Localization and Dicke Superradiance in Atomic Gases  

NASA Astrophysics Data System (ADS)

Photon propagation in a gas of N atoms is studied using an effective Hamiltonian describing photon-mediated atomic dipolar interactions. The density P(?) of photon escape rates is determined from the spectrum of the N×N random matrix ?ij=sin?(xij)/xij, where xij is the dimensionless random distance between any two atoms. Varying disorder and system size, a scaling behavior is observed for the escape rates. It is explained using microscopic calculations and a stochastic model which emphasizes the role of cooperative effects in photon localization and provides an interesting relation with statistical properties of “small world networks.”

Akkermans, E.; Gero, A.; Kaiser, R.

2008-09-01

430

Collective two-particle resonances induced by photon entanglement  

SciTech Connect

An assembly of noninteracting atoms may become correlated upon interaction with entangled photons, and certain elements of their joint density matrix can then show collective resonances. We explore experimental signatures of these resonances in the nonlinear response of a pair of two-level atoms. We find that these resonances are canceled out in stimulated signals such as pump-probe and two-photon absorption due to the destructive interference of two-photon-absorption and emission pathways in the joint two-particle space. However, they may be observed in photon statistics (Hanbury-Brown-Twiss) measurements through the attenuation of two-time intensity correlations.

Richter, Marten [Department of Chemistry, University of California, Irvine, California 92697-2025 (United States); Institut fuer Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Technische Universitaet Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Mukamel, Shaul [Department of Chemistry, University of California, Irvine, California 92697-2025 (United States)

2011-06-15

431

Antibunching photons in a cavity coupled to an optomechanical system  

NASA Astrophysics Data System (ADS)

We study the photon statistics of a cavity linearly coupled to an optomechanical system via second-order correlation functions. Our calculations show that the cavity can exhibit strong photon antibunching even when optomechanical interaction in the optomechanical system is weak. The cooperation between the weak optomechanical interaction and the destructive interference between different paths for two-photon excitation leads to the efficient antibunching effect. Compared with the standard optomechanical system, the coupling between a cavity and an optomechanical system provides a method to relax the constraints to obtain a single photon by optomechanical interaction.

Xu, Xun-Wei; Li, Yuan-Jie

2013-02-01

432

Singular statistics revised  

NASA Astrophysics Data System (ADS)

In this paper, we analyze the 'singular statistics' of pseudointegrable Šeba billiards, i.e. billiards perturbed by zero-range perturbations. We have shown that the computation of a spectrum is reduced to the calculation of the uniquely defined renormalized Green's function. We relate a spectrum of the billiard to the scattering length, which is the only parameter describing the perturbation. We show that taking into account the growing number of resonances, one observes a transition from 'semi-Poissonian'-like statistics to Poissonian. This observation is in agreement with the argument that a classical particle does not feel a point perturbation.

Tudorovskiy, T.; Kuhl, U.; Stöckmann, H.-J.

2010-12-01

433

Bose-Einstein condensation of photons in a 'white-wall' photon box  

NASA Astrophysics Data System (ADS)

Bose-Einstein condensation, the macroscopic ground state occupation of a system of bosonic particles below a critical temperature, has been observed in cold atomic gases and solid-state physics quasiparticles. In contrast, photons do not show this phase transition usually, because in Planck's blackbody radiation the particle number is not conserved and at low temperature the photons disappear in the walls of the system. Here we report on the realization of a photon Bose-Einstein condensate in a dye-filled optical microcavity, which acts as a "white-wall" photon box. The cavity mirrors provide a trapping potential and a non-vanishing effective photon mass, making the system formally equivalent to a two-dimensional gas of trapped massive bosons. Thermalization of the photon gas is reached in a number conserving way by multiple scattering off the dye molecules. Signatures for a BEC upon increased photon density are: a spectral distribution that shows Bose-Einstein distributed photon energies with a macroscopically populated peak on top of a broad thermal wing, the observed threshold of the phase transition showing the predicted absolute value and scaling with resonator geometry, and condensation appearing at the trap centre even for a spatially displaced pump spot.

Klärs, Jan; Schmitt, Julian; Vewinger, Frank; Weitz, Martin

2011-01-01

434

Number Fun  

NSDL National Science Digital Library

We will work on number sense. Play a fun counting game. IXL Counting Review Help Curious George count chicks! Count Your Chickens! Help Sagwa count the fish. Counting Fish Rescue the octopi by counting! Octopus Count Play the five frame games! Five Frame Game ...

Hoffmann, Mrs.

2011-08-05

435

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

436

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

437

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.

438

Number Sense!  

NSDL National Science Digital Library

Perform operations with whole numbers, simple fractions, and decimals. 1. Begin your work at the Comparing Fractions website. Complete 10 problems. 2. When you are finished Comparing Fractions, I\\'m sure you will hunger for more! Click on the website, Who Wants Pizza? These activities are sure to fill your brain with nutritious information. 3. Explore Egyptian ...

Painter, Ms.

2006-10-27

439

Number Pairs  

NSDL National Science Digital Library

With this interactive Flash applet students make use of complements of 10 to develop fluency with addition within 100. Users "repair" a water slide by selecting pairs of numbers that add to 20 in the first round, and then to 100. In successive rounds they may choose to practice with any multiple of 10 from 30 to 90.

Bunker, Dan

2010-01-01

440

Statistics of radiation at Josephson parametric resonance  

NASA Astrophysics Data System (ADS)

Motivated by recent experiments, we study theoretically the full counting statistics of radiation emitted below the threshold of parametric resonance in a Josephson-junction circuit. In contrast to most optical systems, a significant part of emitted radiation can be collected and converted to an output signal. This permits studying the correlations of the radiation. To quantify the correlations, we derive a closed expression for full counting statistics in the limit of long measurement times. We demonstrate that the statistics can be interpreted in terms of uncorrelated bursts, each encompassing 2N photons; this accounts for the bunching of the photon pairs produced in the course of the parametric resonance. We present the details of the burst rates. In addition, we study the time correlations within the bursts and discuss experimental signatures of the statistics deriving the frequency-resolved cross-correlations.

Padurariu, Ciprian; Hassler, Fabian; Nazarov, Yuli V.

2012-08-01

441

Quantifying Variations In Multiparameter Models With The Photon Clean Method (PCM) And Bootstrap Methods  

Microsoft Academic Search

We present examples of an analysis progression consisting of a synthesis of the Photon Clean Method (Carpenter, Jernigan, Brown, Beiersdorfer 2007) and bootstrap methods to quantify errors and variations in many-parameter models. The Photon Clean Method (PCM) works well for model spaces with large numbers of parameters proportional to the number of photons, therefore a Monte Carlo paradigm is a

Matthew H. Carpenter; J. G. Jernigan

2007-01-01

442

Influence of phase modulation on two-photon coherent interaction of light pulses with resonant media  

Microsoft Academic Search

An analysis is made of the influence of the phase modulation and Stark shift of levels on the coherence of light pulses propagating in media with a two-photon resonant interaction. An analytic solution is obtained for the case of two pulses, each carrying the same number of photons. The case of arbitrary numbers of photons in light pulses is also

I A Poluéktov; Yurii M Popov; V S Ro?tberg

1977-01-01

443

Quantum optics in photonic crystals  

Microsoft Academic Search

We survey basic quantum optical processes that undergo modifications in photonic crystals doped with resonant atoms: (a) Solitons and multi-dimensional localized 'bullets' propagating at photonic band gap frequencies. These novel entities differ substantially from solitons in Kerr-nonlinear photonic crystals. (b) Giant photon-photon cross-coupling that can give rise to fully entangled two-photon states. We conclude that doped photonic crystals have the

Gershon Kurizki; Tomas Opatrny; David Petrosyan; Miriam Blaauboer

2002-01-01

444

Bead Numbers  

NSDL National Science Digital Library

This page links to an interactive Flash abacus that helps develop and reinforce pupils' understanding of place value. [Click "Start the Activity" to begin.] The abacus has three pegs (representing units, tens and hundreds) onto which users drop beads. The activity has two areas: a "free" (unstructured) area where pupils can represent 3-digit numbers, and a "computer questions" area that presents six challenging tasks to carry out. The page includes notes for teachers and pupils.

Netmedia

2011-01-01

445

Value Numbering  

Microsoft Academic Search

SUMMARY Value numbering is a compiler-based program analysis method that allows redundant computations to be removed. This paper compares hash-based approaches derived from the classic local algorithm1 with partitioning approaches based on the work of Alpern, Wegman, and Zadeck2. Historically, the hash-based algorithm has been applied to single basic blocks or extended basic blocks. We have improved the technique to

Preston Briggs; Keith D. Cooper; L. Taylor Simpson

1997-01-01

446

Optomechanical generation of a photonic Bose-Einstein condensate  

NASA Astrophysics Data System (ADS)

We propose to thermalize a low-dimensional photon gas and obtain photonic Bose-Einstein condensation by optomechanical interactions in a microscopic optical cavity, with a single longitudinal mode and many transverse modes. The geometry of the short cavity is such that it provides a low-frequency cutoff at a photonic energy far above the thermal energy, so that thermal emission of photons is suppressed and the photon number is conserved. While previous experiments on photonic Bose-Einstein condensation have used dye molecules for photon gas thermalization, we here investigate thermalization owing to interactions with thermally fluctuating nanomechanical oscillators forming the cavity mirrors. In the quantum degenerate regime, the nanomechanical cavity converts broadband optical radiation into tuneable coherent radiation.

Weitz, Martin; Klaers, Jan; Vewinger, Frank

2013-10-01

447

Statistical Neurodynamics.  

NASA Astrophysics Data System (ADS)

The primary objective of the thesis is to explore the dynamical properties of small nerve networks by means of the methods of statistical mechanics. To this end, a general formalism is developed and applied to elementary groupings of model neurons which are driven by either constant (steady state) or nonconstant (nonsteady state) forces. Neuronal models described by a system of coupled, nonlinear, first-order, ordinary differential equations are considered. A linearized form of the neuronal equations is studied in detail. A Lagrange function corresponding to the linear neural network is constructed which, through a Legendre transformation, provides a constant of motion. By invoking the Maximum-Entropy Principle with the single integral of motion as a constraint, a probability distribution function for the network in a steady state can be obtained. The formalism is implemented for some simple networks driven by a constant force; accordingly, the analysis focuses on a study of fluctuations about the steady state. In particular, a network composed of N noninteracting neurons, termed Free Thinkers, is considered in detail, with a view to interpretation and numerical estimation of the Lagrange multiplier corresponding to the constant of motion. As an archetypical example of a net of interacting neurons, the classical neural oscillator, consisting of two mutually inhibitory neurons, is investigated. It is further shown that in the case of a network driven by a nonconstant force, the Maximum-Entropy Principle can be applied to determine a probability distribution functional describing the network in a nonsteady state. The above examples are reconsidered with nonconstant driving forces which produce small deviations from the steady state. Numerical studies are performed on simplified models of two physical systems: the starfish central nervous system and the mammalian olfactory bulb. Discussions are given as to how statistical neurodynamics can be used to gain a better understanding of the behavior of these systems.

Paine, Gregory Harold

1982-03-01

448

Cancer Statistics for Hispanics, 2003  

Microsoft Academic Search

In this article, the American Cancer Society (ACS) provides estimates on the number of new cancer cases and deaths, and compiles health statistics on the US Hispanic population. The compiled statistics include cancer incidence, mortality, and behaviors relevant to cancer using the most recent data on incidence from the National Cancer Institute's (NCI) Surveillance, Epidemiology, and End Results (SEER) Program,

Kathryn O'Brien; Vilma Cokkinides; Ahmedin Jemal; Cheryll J. Cardinez; Taylor Murray; Alicia Samuels; Elizabeth Ward; Michael J. Thun

449

Approximation theory of output statistics  

Microsoft Academic Search

Given a channel and an input process we study the minimum randomness of those input processes whose output statistics approximate the original out- put statistics with arbitrary accuracy. We introduce the notion of resolva- bility of a channel, defined as the number of random bits required per channel use in order to generate an input that achieves arbitrarily accu- rate

Te Sun Han; Sergio Verdii

1993-01-01

450

Digest of Education Statistics, 1992.  

National Technical Information Service (NTIS)

The publication contains information on a variety of subjects in the field of education statistics, including the number of schools and colleges, teachers, enrollments, and graduates, in addition to educational attainment, finances, Federal funds for educ...

J. E. Griffith T. D. Snyder

1992-01-01

451

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.

452

Bose-Einstein condensation of photons  

NASA Astrophysics Data System (ADS)

Bose-Einstein condensation, the macroscopic ground state accumulation of particles with integer spin (bosons) at low temperature and high density, has been observed in several physical systems, including cold atomic gases and solid state physics quasiparticles. However, the most omnipresent Bose gas, blackbody radiation (radiation in thermal equilibrium with the cavity walls) does not show this phase transition. The photon number is not conserved when the temperature of the photon gas is varied (vanishing chemical potential), and at low temperatures photons disappear in the cavity walls instead of occupying the cavity ground state. Here I will describe an experiment observing a Bose-Einstein condensation of photons in a dye-filled optical microcavity [1]. The cavity mirrors provide both a confining potential and a non-vanishing effective photon mass, making the system formally equivalent to a two-dimensional gas of trapped, massive bosons. By multiple scattering of the dye molecules, the photons thermalize to the temperature of the dye solution. In my talk, I will begin with a general introduction and give an account of current work and future plans of the Bonn photon gas experiment. [4pt] [1] J. Klaers, J. Schmitt, F. Vewinger, and M. Weitz, Nature 468, 545 (2010).

Weitz, Martin

2012-02-01

453

Multiphoton state engineering by heralded interference between single photons and coherent states  

NASA Astrophysics Data System (ADS)

We develop a technique for generating multiphoton nonclassical states via interference between coherent and Fock states using quantum catalysis. By modulating the coherent field strength, the number of catalyst photons, and the ratio of the beam splitter upon which they interfere, a wide range of nonclassical phenomena can be created, including squeezing of up to 1.25 dB, antibunched and superbunched photon statistics, and states exhibiting over 90% fidelity to displaced coherent superposition states. We perform quantum catalysis experimentally, showing tunability into the nonclassical regime. Our protocol is not limited by weak nonlinearities that underlie most known strategies of preparing multiphoton nonclassical states. Successive iterations of this protocol can lead to direct control over the weights of higher-order terms in the Fock basis, paving the way towards conditional preparation of “designer” multiphoton states for applications in quantum computation, communication, and metrology.

Bartley, Tim J.; Donati, Gaia; Spring, Justin B.; Jin, Xian-Min; Barbieri, Marco; Datta, Animesh; Smith, Brian J.; Walmsley, Ian A.

2012-10-01

454

Fermat Numbers and Mersenne Numbers.  

National Technical Information Service (NTIS)

An IBM 7090 computer program, and results of testing Mersenne numbers M sub p = (2 raised to the power p) - 1 with p prime, p < 5000, have been described by Hurwitz. This paper describes modifications made to his program, and further computational results...

J. L. Selfridge A. Hurwitz

1968-01-01

455

Multi-Photon Fluorescence Spectroscopy of Fluorescent Bio-Probes and Bio-Molecules.  

National Technical Information Service (NTIS)

Multi-photon fluorescence spectra of a number of commonly used biological probes were measured in this study. Significant spectral variation has been detected between single and multi-photon excitation. The result is important for the proper selection of ...

B. Lin C. Sun F. Kao P. Cheng Y. Wang

2000-01-01

456

Occupational Employment Statistics  

NSDL National Science Digital Library

US occupations are featured in this information-rich resources from the Bureau of Labor Statistics. The 1996 Occupational Employment Statistics Survey differs from previous surveys in that it includes wage data by occupation for the first time. The site contains a description of the survey and complete national and state data for 760 occupations in seven major areas. Included are occupation title, number of employees, hourly mean and median wage, and an OES code number that provides information about the occupation and its employment distribution by wage range where surveyed (distribution is for the national survey only). An occupational search engine is forthcoming. The site also contains information about previous OES surveys back to 1988.

457

Two-photon physics  

SciTech Connect

A new experimental frontier has recently been opened to the study of two photon processes. The first results of many aspects of these reactions are being presented at this conference. In contrast, the theoretical development of research ito two photon processes has a much longer history. This talk reviews the many different theoretical ideas which provide a detailed framework for our understanding of two photon processes.

Bardeen, W.A.

1981-10-01

458

National Photonics Skill Standards  

NSDL National Science Digital Library

This document marks an important milestone in the development and maintenance of high-quality associate degree programs in photonics in U.S. community and technical colleges. The need for photonics education is critical. The problem cannot be remedied through on-the-job training. Our public educational institutions, particularly two-year colleges, must get involved. But most cannot do so without guidelines for determining what knowledge and skills photonics graduates will need in the coming years.

2008-11-17

459

Monte Carlo evaluation of kerma at a point for photon transport problems  

SciTech Connect

Estimation of collision kerma at a geometric point arising from scattered photons is a potentially important application of Monte Carlo simulation, especially in the presence of steep flux gradients. We examine the usual method of extracting point-kerma estimates from randomly generated photon trajectories which consists of tallying the energy lost by photon collisions occurring in the vicinity of the point of interest. Several other methods derived from the equivalence of track length per unit volume and flux are evaluated as to accuracy and efficiency. Finally, a next-flight estimator is discussed in which the expected contribution of each simulated photon collision to kerma at the point of interest is calculated regardless of proximity of the collision to the point. All of these techniques are shown to involve a trade-off between statistical precision and spatial resolution: increasing the number of contributing collisions requires averaging kerma over a larger volume. Based upon both analytic models and realistic Monte Carlo simulations, use of next-flight and track-length estimators is shown to improve simulation efficiencies by factors of 2 to 20 compared to analog scoring. Practical guidelines as to choice of estimator and successful implementation are presented.

Williamson, J.F.

1987-07-01

460

Two-photon imaging and spectroscopy of fresh human colon biopsies  

NASA Astrophysics Data System (ADS)

Two-photon fluorescence (TPEF) microscopy is a powerful tool to image human tissues up to 200 microns depth without any exogenously added probe. TPEF can take advantage of the autofluorescence of molecules intrinsically contained in a biological tissue, as such NADH, elastin, collagen, and flavins. Two-photon microscopy has been already successfully used to image several types of tissues, including skin, muscles, tendons, bladder. Nevertheless, its usefulness in imaging colon tissue has not been deeply investigated yet. In this work we have used combined two-photon excited fluorescence (TPEF), second harmonic generation microscopy (SHG), fluorescence lifetime imaging microscopy (FLIM), and multispectral two-photon emission detection (MTPE) to investigate different kinds of human ex-vivo fresh biopsies of colon. Morphological and spectroscopic analyses allowed to characterize both healthy mucosa, polyp, and colon samples in a good agreement with common routine histology. Even if further analysis, as well as a more significant statistics on a large number of samples would be helpful to discriminate between low, mild, and high grade cancer, our method is a promising tool to be used as diagnostic confirmation of histological results, as well as a diagnostic tool in a multiphoton endoscope or colonoscope to be used in in-vivo imaging applications.

Cicchi, R.; Sturiale, A.; Nesi, G.; Tonelli, F.; Pavone, F. S.

2012-02-01

461

Statistics of citation networks  

Microsoft Academic Search

The out-degree distribution of citation networks is investigated. Statistical data of the number of papers cited within a paper (out-degree) for different journals in the period 1991-1999 is reported. The out-degree distribution is characterized by a maximum at intermediate out-degrees. At the left of the maximum there are strong fluctuations from journal to journal while is quite universal at the

Alexei Vazquez

2001-01-01

462

Bose-Einstein condensation of photons in an optical microcavity.  

PubMed

Bose-Einstein condensation (BEC)-the macroscopic ground-state accumulation of particles with integer spin (bosons) at low temperature and high density-has been observed in several physical systems, including cold atomic gases and solid-state quasiparticles. However, the most omnipresent Bose gas, blackbody radiation (radiation in thermal equilibrium with the cavity walls) does not show this phase transition. In such systems photons have a vanishing chemical potential, meaning that their number is not conserved when the temperature of the photon gas is varied; at low temperatures, photons disappear in the cavity walls instead of occupying the cavity ground state. Theoretical works have considered thermalization processes that conserve photon number (a prerequisite for BEC), involving Compton scattering with a gas of thermal electrons or photon-photon scattering in a nonlinear resonator configuration. Number-conserving thermalization was experimentally observed for a two-dimensional photon gas in a dye-filled optical microcavity, which acts as a 'white-wall' box. Here we report the observation of a Bose-Einstein condensate of photons in this system. The cavity mirrors provide both a confining potential and a non-vanishing effective photon mass, making the system formally equivalent to a two-dimensional gas of trapped, massive bosons. The photons thermalize to the temperature of the dye solution (room temperature) by multiple scattering with the dye molecules. Upon increasing the photon density, we observe the following BEC signatures: the photon energies have a Bose-Einstein distribution with a massively populated ground-state mode on top of a broad thermal wing; the phase transition occurs at the expected photon density and exhibits the predicted dependence on cavity geometry; and the ground-state mode emerges even for a spatially displaced pump spot. The prospects of the observed effects include studies of extremely weakly interacting low-dimensional Bose gases and new coherent ultraviolet sources. PMID:21107426

Klaers, Jan; Schmitt, Julian; Vewinger, Frank; Weitz, Martin

2010-11-25

463

Uncertainty relation for photons.  

PubMed

The uncertainty relation for the photons in three dimensions that overcomes the difficulties caused by the nonexistence of the photon position operator is derived in quantum electrodynamics. The photon energy density plays the role of the probability density in configuration space. It is shown that the measure of the spatial extension based on the energy distribution in space leads to an inequality that is a natural counterpart of the standard Heisenberg relation. The equation satisfied by the photon wave function in momentum space which saturates the uncertainty relations has the form of the Schrödinger equation in coordinate space in the presence of electric and magnetic charges. PMID:22540772

Bialynicki-Birula, Iwo; Bialynicka-Birula, Zofia

2012-04-03

464

Entangled Photon Holes  

NASA Astrophysics Data System (ADS)

Entangled photon hole (EPH) states represent a new form of entanglement that is based on the existence of ``missing pairs'' of photons in two optical modes. In contrast to the more familiar photon pairs entangled in polarization or other variables, the entanglement in EPH states arises from the absence of the photon pairs themselves. We will review recent experimental work on the generation of these states, and theoretical work showing that they can be relatively insensitive to loss and amplification noise in certain situations. We will also report on our recent efforts to generate time-bin EPH states which have different properties than energy-time EPH states.

Pittman, Todd; Liang, Junlin; Franson, James

2013-03-01

465

Photons with Momentum Along Curved Paths  

NASA Astrophysics Data System (ADS)

Electromagnetic energy flow is expressed mathematically by the Poynting Vector. Quantum theory determines that the Poynting Vector provides the direction of movement of the photons which are the quanta of the electromagnetic field. In this dissertation important phenomena featuring the flow of electromagnetic energy—and hence transport of photons—along curved paths are investigated. A circuit is considered in the shape of a ring, with a battery of negligible size and a wire of uniform resistance. A linear charge distribution in the wire generates an electrostatic field and a steady current through the circuit which maintains a constant magnetic field. Earlier studies of the Poynting vector and the rate of flow of energy considered only idealized geometries in which the Poynting vector was confined to the space within the circuit. But in more realistic cases the Poynting vector is nonzero outside as well as inside the circuit. An expression is obtained for the Poynting vector in terms of products of integrals, which are evaluated numerically to show the energy flow. Limiting expressions are obtained analytically. It is shown that the total power generated by the battery equals the energy flowing into the wire per unit time. Whereas the Poynting Vector flows along the direction of propagation of a plane wave photon, it is a different matter with photons described by Laguerre-Gaussian transverse profiles. Such "twisted" photon beams have a spiraling Poynting Vector that generates an orbital angular momentum that is distinct from the photon's spin angular momentum. The transverse confinement of the twisted photon beam gives rise to a Gouy phase shift, and the transverse structure of this phase shift is characterized by the Gouy radius. A new expression is obtained for this radius in terms of the parameters w, p, and ? of the Laguerre-Gaussian beam profile. The orbital angular momentum states have a two-fold degeneracy with respect to the winding number or topological charge, the degeneracy being suitable for encoding qubits. The conditions under which such a photon qubit could flip through exchange of angular momentum with the atoms of a medium are investigated and an expression obtained for the matrix elements of such transitions. Whereas a plane wave photon has only a longitudinal Poynting Vector, in the case of a twisted photon there is also a transverse azimuthal Poynting Vector flow. This suggests that photonic orbital angular momentum may have a component oscillating with a frequency of 2? where ? is the polarization or spin frequency of the photon. Thus the orbital angular momentum is a manifestation of photonic zitterbewegung.

Davis, Basil S.

466

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

467

Photon blockade in circuit quantum electrodynamics  

NASA Astrophysics Data System (ADS)

Strong photon-photon interactions arise in a cavity strongly coupled to an atom or qubit, resulting in blockaded transmission[1]. In such a system, the resonant frequency of the cavity shifts with the presence of a single photon due to the strong number-dependent nature of the cavity nonlinearity. Here, we investigate the photon blockade regime in superconducting circuits with integrated transmon qubits. To maximize the nonlinear effects, both the cavity Q and qubit-cavity coupling are made extremely large by design, with Q exceeding 100,000. Cavity transmission is characterized using a microwave generator with a controllable output bandwidth. Measurements of transmitted power and spectra versus incident center frequency and bandwidth are presented. [1] K.M. Birnbaum et al., Nature, 436, 87 (2005).

Hoffman, Anthony; Srinivasan, Srikanth; Shim, Beumseok; Houck, Andrew

2010-03-01

468

Multi-photon optical rotation by molecules  

NASA Astrophysics Data System (ADS)

Forward scattering of polarized light by a chiral molecule results in optical rotation. Ordinary optical rotation, a single-photon effect, is independent of intensity, I. Multi-photon optical rotation is proportional to I^N-1, where N is the number of photons involved the scattering event. The ordinary optical rotation changes with temperature, and so the absorption of light can also cause an intensity-dependent change in optical rotation. We used a polarimeter to measure the change in optical rotation with light intensity for several molecules in solution: sucrose, borneol, uridine and phenylalanine. Making use of Faraday rotation, we added a time-dependent rotation of the light to our apparatus. This allowed us to use Fourier analysis to separate the multi-photon optical rotation from the temperature change in ordinary optical rotation and improved the signal-to-noise.

Cameron, R.; Tabisz, G. C.

2001-05-01

469

Intermediate-statistics spin waves  

NASA Astrophysics Data System (ADS)

In this paper, we show that spin waves, the elementary excitation of the Heisenberg magnetic system, obey a kind of intermediate statistics with a finite maximum occupation number n. We construct an operator realization for the intermediate statistics obeyed by magnons, the quantized spin waves, and then construct a corresponding intermediate-statistics realization for the angular momentum algebra in terms of the creation and annihilation operators of the magnons. In other words, instead of the Holstein-Primakoff representation, a bosonic representation subject to a constraint on the occupation number, we present an intermediate-statistics representation with no constraints. In this realization, the maximum occupation number is naturally embodied in the commutation relation of creation and annihilation operators, while the Holstein-Primakoff representation is a bosonic operator relation with an additional putting-in-by-hand restriction on the occupation number. We deduce the intermediate-statistics distribution function for magnons from the intermediate-statistics commutation relation of the creation and annihilation operators directly, which is a modified Bose-Einstein distribution. On the basis of these results, we calculate the dispersion relations for ferromagnetic and antiferromagnetic spin waves. The relations between the intermediate statistics that magnons obey and the other two important kinds of intermediate statistics, Haldane-Wu statistics and the fractional statistics of anyons, are discussed. We also compare the spectrum of the intermediate-statistics spin wave with the exact solution of the one-dimensional s = 1/2 Heisenberg model, which is obtained by the Bethe ansatz method. For ferromagnets, we take the contributions from the interaction between magnons (the quartic contribution), the next-to-nearest-neighbor interaction, and the dipolar interaction into account for comparison with the experiment.

Dai, Wu-Sheng; Xie, Mi

2009-04-01

470

Identification of Intensity Ratio Break Points from Photon Arrival Trajectories in Ratiometric Single Molecule Spectroscopy  

PubMed Central

We describe a statistical method to analyze dual-channel photon arrival trajectories from single molecule spectroscopy model-free to identify break points in the intensity ratio. Photons are binned with a short bin size to calculate the logarithm of the intensity ratio for each bin. Stochastic photon counting noise leads to a near-normal distribution of this logarithm and the standard student t-test is used to find statistically significant changes in this quantity. In stochastic simulations we determine the significance threshold for the t-test’s p-value at a given level of confidence. We test the method’s sensitivity and accuracy indicating that the analysis reliably locates break points with significant changes in the intensity ratio with little or no error in realistic trajectories with large numbers of small change points, while still identifying a large fraction of the frequent break points with small intensity changes. Based on these results we present an approach to estimate confidence intervals for the identified break point locations and recommend a bin size to choose for the analysis. The method proves powerful and reliable in the analysis of simulated and actual data of single molecule reorientation in a glassy matrix.

Bingemann, Dieter; Allen, Rachel M.

2012-01-01

471

Density Control for Photon Maps  

Microsoft Academic Search

The photon map method allows efficient computation of global illumination in general scenes. Individual photon hits, generated using Monte Carlo particle tracing, are stored in the maps and form a geometry independent representation of the illumination. Two important issues with the photon map are memory requirements to store the photons and the question how many photons are n