共查询到20条相似文献,搜索用时 46 毫秒
1.
Wei Bin Yan 《Optics Communications》2010,283(2):265-269
The frequency conversion and entanglement is studied via polariton technique. We analyze the effect of detuning on the efficiency of frequency conversion (EFC). The results show that by adjusting the second mode frequency, the EFC still can be achieved perfectly when the incoming photon is off-resonant. The effect of the spontaneous emission of the atoms on EFC is included. 相似文献
2.
Spontaneous parametric downconversion (SPDC) is widely used to generate entangled photon pairs; however, multi-pair emissions degrade the quality of the entanglement. We numerically evaluate polarization-entangled photon pairs created by SPDC. The effects of multi-pair emission events on the visibility of two-photon interference and on the fidelity (the probability overlap for ideal and real states) are analyzed using single-photon detectors that can count the number of incoming photons and discard multiphoton events. Compared with conventional threshold single-photon detectors, photon-number resolving single-photon detectors have higher fidelity for the same or lower visibility. 相似文献
3.
We study the interplay of photons interacting with an artificial atom in the presence of a controlled dephasing. Such artificial atoms consisting of several independent scatterers can exhibit remarkable properties superior to single atoms with a prominent example being a superatom based on Rydberg blockade. We demonstrate that the induced dephasing allows for the controlled absorption of a single photon from an arbitrary incoming probe field. This unique tool in photon-matter interaction opens a way for building novel quantum devices, and several potential applications such as a single photon transistor, high fidelity n-photon counters, or the creation of nonclassical states of light by photon subtraction are presented. 相似文献
4.
Mass spectrometric measurements of photodesorption from powdered ZnO under controlled radiation are reported. Neutral carbon dioxide and atomic oxygen prevail as the desorbing species. From photodesorption rate decay curves we obtain cross sections for photodesorption of ~ 2 × 10?17 cm2 for O and ~4 × 10?19 cm2 for CO2. Both species desorb only when the incoming photon energy exceeds the ZnO band gap energy (3.2 eV). The desorption rate is linear with incoming photon flux. All the data seem to support a substrate dependent process of photodesorption by neutralization of chemisorbed species by photogenerated holes. The temperature dependence of the photodesorption rate for CO2 yields a value of 0.26 eV for the apparent binding energy of the physisorbed CO2 molecule. 相似文献
5.
Lodahl P 《Optics letters》2006,31(1):110-112
Frequency correlations in multiply scattered light that are present in quantum fluctuations are investigated. The speckle correlations for quantum and classical noise are compared and are found to depend markedly differently on optical frequency, which was confirmed in a recent experiment. Furthermore, novel mesoscopic correlations are predicted that depend on the photon statistics of the incoming light. 相似文献
6.
We investigate the effect of the dipole–dipole interaction(DDI) on the photon statistics with two atoms trapped in an optical cavity driven by a laser field and subjected to cooperative emission. By means of the quantum trajectory analysis and the second-order correlation functions, we show that the photon statistics of the cavity transmission can be flexibly modulated by the DDI while the incoming coherent laser selectively excites the atom–cavity system's nonlinear Jaynes–Cummings ladder of excited states. Finally, we find that the effect of the cooperatively atomic emission can also be revealed by the numerical simulations and can be explained with a simplified picture. The DDI induced nonlinearity gives rise to highly nonclassical photon emission from the cavity that is significant for quantum information processing and quantum communication. 相似文献
7.
Deeply virtual Compton scattering has been proposed as a tool to study the structure of hadrons in an exclusive process. The Compton-scattering amplitude can be expressed in terms of scalar quantities, the Compton form factors. Their number depends on the spin of the target as well as the virtuality of the incoming and outgoing photons. For high values of the virtuality Q 2 of the incoming photon, these form factors are expected to scale with inverse powers of Q 2. In this paper these features are studied for a scalar target hadron. 相似文献
8.
The ZEUS Collaboration S. Chekanov et al. 《The European Physical Journal C - Particles and Fields》2002,23(4):615-631
The dijet cross section in photoproduction has been measured with the ZEUS detector at HERA using an integrated luminosity
of 38.6 pb. The events were required to have a virtuality of the incoming photon, , of less than 1 GeV and a photon-proton centre-of-mass energy in the range GeV. Each event contains at least two jets satisfying transverse-energy requirements of GeV and GeV and pseudorapidity requirements of \mbox{}. The measurements are compared to next-to-leading-order QCD predictions. The data show particular sensitivity to the density
of partons in the photon, allowing the validity of the current parameterisations to be tested.
Received: 21 December 2001 / Published online: 5 April 2002 相似文献
9.
One can use a single optical cavity as the simplest possible resonator in order to ascertain the presence of an object with
an arbitrarily low portion of an incoming laser beam. In terms of individual photons, each photon nonrepeatedly tests the
object with an arbitrarily high probability of detecting its presence without interacting with it. 相似文献
10.
Characterization of a quadrant diamond transmission X‐ray detector including a precise determination of the mean electron–hole pair creation energy 下载免费PDF全文
Jeffrey W. Keister Levent Cibik Swenja Schreiber Michael Krumrey 《Journal of synchrotron radiation》2018,25(2):407-412
Precise monitoring of the incoming photon flux is crucial for many experiments using synchrotron radiation. For photon energies above a few keV, thin semiconductor photodiodes can be operated in transmission for this purpose. Diamond is a particularly attractive material as a result of its low absorption. The responsivity of a state‐of‐the art diamond quadrant transmission detector has been determined, with relative uncertainties below 1% by direct calibration against an electrical substitution radiometer. From these data and the measured transmittance, the thickness of the involved layers as well as the mean electron–hole pair creation energy were determined, the latter with an unprecedented relative uncertainty of 1%. The linearity and X‐ray scattering properties of the device are also described. 相似文献
11.
A. G. Stepanov S. Henin Y. Petit L. Bonacina J. Kasparian J.-P. Wolf 《Applied physics. B, Lasers and optics》2010,101(1-2):11-14
The Teramobile laser facility was used to realize the first mobile source of high-power THz pulses. The source is based on a tilted-pulse-front pumping THz generation scheme optimized for application of terawatt laser pulses. Generation of 50-μJ single-cycle electromagnetic pulses centered at 0.19 THz with a repetition rate of 10 Hz was obtained for incoming 700-fs 120-mJ near-infrared laser pulses. The corresponding laser-to-THz photon conversion efficiency is approximately 100%. 相似文献
12.
F. Selleri 《Foundations of Physics》1987,17(8):739-757
The traditional approach to light amplification is shown to be based on the idea that photons of the incoming beam act as independent particles. If atomic stimulation is instead attributed to the action of the wave, a different photon distribution is obtained in the final state. The new distribution turns out to be Poissonian, in agreement with some experimental evidence. The expected rate of coincidences for an empty-wave amplification experiment is calculated, and found up to 30% higher than obtained from the traditional approach. 相似文献
13.
14.
J. Raufeisen A.V. Tarasov O.O. Voskresenskaya 《The European Physical Journal A - Hadrons and Nuclei》1999,5(2):173-182
In the rest frame of the nucleus, shadowing is due to hadronic fluctuations of the incoming virtual photon, which interact with the nucleons. We expand these fluctuations in a basis of eigenstates of the interaction and take only the q¥q component of the hadronic structure of the photon into account. We use a representation in which the q¥q-pair has a definite transverse size. Starting from the Dirac equation, we develop a path integral approach that allows to sum all multiple scattering terms and accounts for fluctuations of the transverse size of the pair, as well as for the finite lifetime of the hadronic state. First numerical results show that higher order scattering terms have a strong influence on the total cross section C%*Atot. The aim of this paper is to give a detailed derivation of the formula for the total cross section. 相似文献
15.
I.F. Ginzburg U.D. Jentschura V.G. Serbo 《The European Physical Journal C - Particles and Fields》2008,54(2):267-276
Delbrück scattering is the elastic scattering of a photon in the Coulomb field of a nucleus via a virtual electron loop. The
contribution of this virtual subprocess to the emission of a photon in the collision of ultra-relativistic nuclei, Z1Z2→Z1Z2γ, is considered. We identify the incoming virtual photon as being generated by one of the relativistic nuclei involved in
the binary collision and the scattered photon as being emitted in the process. The energy and angular distributions of the
photons are calculated. The discussed process has no infrared divergence. The total cross section obtained is 14 barn for
Au–Au collisions at the RHIC collider and 50 barn for Pb–Pb collisions at the LHC collider. These cross sections are considerably
larger than those for ordinary tree-level nuclear bremsstrahlung in the considered photon energy range, me⪡Eγ⪡meγ, where γ is the Lorentz factor of the nucleus. Finally, photon emission in electron–nucleus collisions, eZ→eZγ, is discussed
in the context of the eRHIC option. 相似文献
16.
We investigate the QCD Compton effect γq→gq by using Monte Carlo, methods to simulate complete three jet events for photon-nucleon interactions. This process provides unique possibilities for jet studies because the incoming photon transfers its entire energy to the final state gluon and quark jets. We present a number of predictions for photons in the range of energies presently available up to Tevatron energies and find that the QCD Compton effect will dominate over vector meson dominance at large gluon transverse momenta. 相似文献
17.
Gutt C Ghaderi T Chamard V Madsen A Seydel T Tolan M Sprung M Grübel G Sinha SK 《Physical review letters》2003,91(7):076104
We report measurements of propagating capillary waves on a liquid water surface at T=5 degrees C with x-ray photon correlation spectroscopy. The experiment has been performed under grazing incidence conditions with an incoming x-ray beam below the critical angle of total external reflection. In the q region investigated the measured intensity-intensity autocorrelation functions of the liquid water surface were found to be heterodyne signals, i.e., a combination of first- and second-order correlation functions g(1)(tau) and g(2)(tau). 相似文献
18.
We investigate the resonant two-magnon Raman scattering in two-dimensional (2D) Mott insulators by using a half-filled 2D Hubbard model in the strong coupling limit. By performing numerical diagonalization calculations for small clusters, we find that the Raman intensity is enhanced when the incoming photon energy is not near the optical absorption edge but well above it, being consistent with experimental data. The absence of resonance near the gap edge is associated with the presence of background spins, while photoexcited states for resonance are found to be characterized by the charge degree of freedom. The resonance mechanism is different from those proposed previously. 相似文献
19.
In the regime of weak nonlinearity we present two general, feasible schemes for manipulating photon states. One is an entangler for generating any one of the n-photon Greenberger-Horne-Zeilinger (GHZ) states. Interactions of the incoming photons with cross-Kerr media followed by a phase shift gate and a measurement on a probe beam plus appropriate local operations using classical feed-forward of the measurement results allow one to obtain the desired states in a nearly deterministic manner. The second scheme discussed is an analyzer for multiphoton maximally entangled states, which is derived from the above entangler. In this scheme, all of the 2 n n-photon GHZ states can, nearly deterministically, be discriminated. 相似文献
20.
Zekiye Isikli 《辐射效应与固体损伤》2017,172(3-4):296-304
The probability of gamma or X-ray interactions with important 14 antioxidants have been discussed for total photon interactions in the wide energy range of 1?keV–100?GeV using the WinXCOM code. The variations of mass attenuation coefficient (μρ), effective atomic number (Zeff) and electron density (Nel) with photon energy were plotted for total photon interactions. It was found that the values of μρ, Zeff and Nel depend on the incoming photon energy and chemical compositions of antioxidant. The highest values of these parameters were found at a low-energy zone where the photoelectric effect is the dominant interaction process. When antioxidants were compared with each other, it was seen that Zeff has the highest values for Oenin chloride and Delphinidin chloride which contain the Cl element. This investigation is thought to be useful for medical applications where radiation exposure is present. 相似文献