共查询到20条相似文献,搜索用时 31 毫秒
1.
The dynamics of correlation of photon number fluctuations of interacting modes for the process of intracavity third subharmonic generation is investigated. It is shown that the entangled field states by the variables of photon number can be obtained in this system. The quantum dynamics of the photons number, the quantum entropy and the Wigner function of the stationary states of the fundamental mode and the third subharmonic mode have also been studied. It is found that the dynamics of these quantities depends highly on the value of the coupling coefficient of the interacting modes. It is shown that at long interaction times and for the large values of the coupling coefficient of the modes, the mode of the third subharmonic is localized in the three-component state with the same probability of detection of the mode in each component of the state. The quantum entropy of the state is less than the maximal entropy of the three-component state ln3, which points out the presence of quantum mechanical interference between the components of the state of third subharmonic mode. 相似文献
2.
A cavity quantum electrodynamics (QED) based approach for transferring quantum state between quantum nodes has been proposed, wherein a rubidium (87Rb) atom trapped inside a two-mode optical cavity forms the quantum node and photons serve as the information carrier between two such nodes. Information is encoded into polarized photon states generated through the application of a system of lasers. The focus is made on the phase-space analysis of the approach, wherein two subspaces of the hyperfine energy levels with magnetic sub-levels of rubidium (87Rb) atom represent the logic states ‘0’ and ‘1’. The system of lasers initiates a cavity assisted Raman process which, in turn, generates a right- or left-circularly polarized photon depending on the logic state of the transmit node. Once the photon is received (at the receive node), the logic state of the transmit node is restored into the receive node through a cavity QED process. 相似文献
3.
4.
Auffeves A Maioli P Meunier T Gleyzes S Nogues G Brune M Raimond JM Haroche S 《Physical review letters》2003,91(23):230405
We observe that a mesoscopic field made of several tens of microwave photons exhibits quantum features when interacting with a single Rydberg atom in a high-Q cavity. The field is split into two components whose phases differ by an angle inversely proportional to the square root of the average photon number. The field and the atomic dipole are phase entangled. These manifestations of photon graininess vanish at the classical limit. This experiment opens the way to studies of large quantum state superpositions at the quantum-classical boundary. 相似文献
5.
T.?H?yrynen J.?Oksanen J.?Tulkki 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,56(1):113-121
The recent experiment of Parigi et al. [Science 317, 1890 (2007)]
shows, in agreement with theory, that subtraction of one photon can increase the expectation value of the number of photons
in the thermal state.
This observation agrees with the standard photon counting model in which
the quantum jump superoperator (QJS) gives a count rate proportional to the number of photons.
An alternate model for indirect photon counting
has been introduced by Dodonov et al. [Phys. Rev. A 72, 023816 (2005)].
In their model the count rate is proportional to the probability that there are photons in the cavity,
and the cavity field is bidirectionally coupled with a two state quantum system
which is unidirectionally coupled to a counting device.
We give a consistent first principle derivation of the QJSs for the indirect photon counting scheme
and establish the complete relations between the physical measurement setup and the QJSs.
It is shown that the time-dependent probability for photoelectron emission event
must include normalization of the conditional probability.
This normalization was neglected in the previous derivation of the QJSs.
We include the normalization and obtain the correct photoelectron emission rates and the correct QJSs
and show in which coupling parameter regimes these QJSs are applicable.
Our analytical results are compared with the exact numerical solution of the Lindblad equation of the
system.
The derived QJSs enable analysis of experimental photon count rates in a case where
a one-to-one correspondence does not exist between the decay of photons and the detection events. 相似文献
6.
Masashi Ban 《International Journal of Theoretical Physics》2018,57(5):1455-1470
Total, classical and quantum correlations as well as entanglement are studied for a two-qubit system, where each qubit is placed in a micro cavity described by the dispersive Jaynes-Cummings model. Not only the loss of cavity photons but also the effect of the qubit-photon interaction on the loss is taken into account. The two-qubit system is initially prepared in a Bell diagonal state with a single mixing parameter and the cavity photon is either in a superposition of vacuum and single-photon states or in a weak coherent state. It is shown that more correlation of the two qubits can survive as an initial value of the cavity photon number is smaller. There is a threshold value of the cavity photon number, below which the stationary state becomes inseparable. Furthermore it is found that the external environment which causes the cavity loss has two effects; one brings about the decay of the correlations and the other suppresses the decay. 相似文献
7.
We propose an entanglement generation scheme that requires neither the coherent evolution of a quantum system nor the detection of single photons. Instead, the desired state is heralded by a macroscopic quantum jump. Macroscopic quantum jumps manifest themselves as a random telegraph signal with long intervals of intense fluorescence (light periods) interrupted by the complete absence of photons (dark periods). Here we show that a system of two atoms trapped inside an optical cavity can be designed such that a dark period prepares the atoms in a maximally entangled ground state. Achieving fidelities above 0.9 is possible even when the single-atom cooperativity parameter is as low as 10 and when using a photon detector with an efficiency as low as eta=0.2. 相似文献
8.
HOU Bang-Pin WANG Shun-Jin WANG Gang SUN Wei-Li 《理论物理通讯》2007,48(2):232-242
When two identical QED cavities driven by the coherent fields are located in a uniform environment, in addition to dissipation, there appears an indirect coupling between the two cavities induced by the background fields. We investigate the effects of the coherent fields, the dissipation as well as the incoherent coupling on the following dynamical properties of the system: photon transfer, reversible decoherence, and quantum state transfer, etc. We find that the photons in the cavities do not leak completely into the environment due to the collective coupling between the cavities and the enviroment, and the photons are transferred irreversibly from the cavity with more photons to the cavity with less ones due to the incoherent coupling so that they are equally distributed among the two cavities. The coherent field pumping on the two cavities increases the mean photons, complements the revived magnitude of the reversible decoherence, but hinders the quantum state transfer between the two cavities. The above phenomena may find applications in quantum communication and other basic fields. 相似文献
9.
When two identical QED cavities driven by the coherent fields are located in a uniform environment, in addition to dissipation, there appears an indirect coupling between the two cavities induced by the background fields. We investigate the effects of the coherent fields, the dissipation as well as the incoherent coupling on the following dynamical properties of the system: photon transfer, reversible decoherence, and quantum state transfer, etc. We find that the photons in the cavities do not leak completely into the environment due to the collective coupling between the cavities and the enviroment, and the photons are transferred irreversibly from the cavity with more photons to the cavity with less ones due to the incoherent coupling so that they are equally distributed among the two cavities. The coherent field pumping on the two cavities increases the mean photons, complements the revived magnitude of the reversible decoherence, but hinders the quantum state transfer between the two cavities. The above phenomena may find applications in quantum communication and other basic fields. 相似文献
10.
We investigate the entropy squeezing and entanglement of the Cooper-pair box interacting with multi-photon cavity field. The field is prepared initially in the coherent state, while the Cooper-pair box is assumed to start from a mixed state. We find that the number of photons and the detuning parameters play an important role in the entropy squeezing and entanglement. We observe that the entropy squeezing can be used as a good indicator of the entanglement. This study opens promising perspectives for creating remote quantum information processing networks. 相似文献
11.
12.
原子系综中的Duan-Lukin-Cirac-Zoller(DLCZ)过程是产生光与原子(量子界面)量子关联和纠缠的重要手段.当一束写光与原子发生作用时,将会产生斯托克斯(Stokes)光子的自发拉曼散射,并同时产生一个自旋波(spin-wave)存储在原子系综中,上述过程即为DLCZ量子记忆产生过程.这一过程被广泛地研究.本文将87Rb原子系综放入驻波腔,并使Stokes光子与光学腔共振,我们观察到有腔且锁定的情况下Stokes光子产生概率比无腔时增大了8.7倍.在此条件下研究了Stokes光子产生概率和写光功率的关系,Stokes光子产生概率随写光功率线性增大. 相似文献
13.
利用全量子理论,研究了多光子Jaynes-Cummings模型中与Glauber-Lachs态相互作用的混合态原子的信息熵压缩。讨论了相干平均光子数、热平均光子数、跃迁光子数、原子初态参量对原子信息熵压缩的影响。结果表明原子信息熵 分量没有熵压缩性质;相干平均光子数取值适当时,原子信息熵 分量呈现熵压缩效应;热平均光子数、跃迁光子数会破坏原子信息熵 分量的熵压缩效应;原子初态参量对原子信息熵 分量能否呈现熵压缩效应没有决定性作用;伴随双光子跃迁时,原子的熵压缩因子的时间演化曲线呈现周期性。 相似文献
14.
We demonstrate how to perform quantum phase gate with cavity QED system in decoherence-free subspace by using only linear optics elements and photon detectors. The qubits are encoded in the singlet state of the atoms in cavities among spatially separated nodes, and the quantum interference of polarized photons decayed from the optical cavities is used to realized the desired quantum operation among distant nodes. In comparison with previous schemes, the distinct advantage is that the gate fidelity could not only resist collective noises, but also immune from atomic spontaneous emission, cavity decay, and imperfection of the photodetectors. We also discuss the experimental feasibility of our scheme. 相似文献
15.
A. V. Kozlovskii 《JETP Letters》2005,82(11):685-689
Dispersive quantum nondemolition measurement of the number of photons is analyzed in the micromaser scheme. It has been shown that the stationary Fock state of the field in a cavity that is considered as the result of quantum nondemolition measurement is realized only in a particular case for strictly determined parameters of the system, and small variation in one of the parameters of the system results in a qualitative change in the field state. In the general case, the field state is characterized by large fluctuations of the number of photons and the mean number of photons, which are very sensitive to the parameters of the system. It has been shown that the detection of the Ramsey interference pattern is possible only when the sequence of atoms passing through the cavity is highly monokinetic. 相似文献
16.
Said Mikki 《Annalen der Physik》2024,536(3):2300288
This study investigates the theoretical aspects of the interaction between photons with mass and a mechanical oscillator as drawn within the framework of cavity optomechanics. The study employs Proca theory as the mathematical framework to initially describe the dynamics of massive photons in a Fabry-Perot cavity with a movable mass, both in classical and quantum scenarios. It quantifies the modifications induced by the nonzero photon mass, considering first- and second-order effects, and derives expressions for the amplification of radiation pressure resulting from the presence of nonzero photon mass. Additionally, it derives the Hamiltonian of the quantum optomechanical system, incorporating the effects of photon mass at first and second order. It anticipates that experimental realization of massive optomechanics can be achieved by utilizing Proca material, which is a spatio-temporally dispersive material that exhibits behavior equivalent to Proca theory in a vacuum, thus enabling the study of the interaction between massive photons and mechanical systems in cavity-based optomechanical setups (referred to as massive cavity optomechanics). The study presented here caters to a diverse audience with an interest in the analysis and measurement of interactions among massive objects at the quantum scale. 相似文献
17.
Salomon S. Mizrahi Alexandre V. Dodonov Victor V. Dodonov 《Journal of Russian Laser Research》2009,30(5):485-492
We propose an experimental scheme to probe the mathematical form of quantum jump operators used in the theory of continuous
photodetection and quantum trajectories in cavities. For this aim, we propose two main steps to be followed in an experimental
design: (1) pass an atom through a high-Q cavity containing an electromagnetic field prepared in a thermal or coherent state, in order to enforce the absorption of
one or more photons and (2) subsequently produce a measurement of the photon statistics in the new field state arising after
the photon absorption. Then, comparing the probabilities of finding zero and one photon in the initial and final states of
the field, one can draw conclusions on the form of the quantum jump operators. This scheme can be readily applied in a QED
microwave cavity with the present-day technology, and it allows experimental investigations of the theory of quantum jumps
due to different kinds of hypothetical reservoirs. 相似文献
18.
Many applications in quantum information or quantum computing require radiation with a fixed number of photons. This increased the demand for systems able to produce such fields. We discuss the production of photon fields with a fixed photon number on demand. The first experimental demonstration of the device is described. This setup is based on a cavity quantum electrodynamics scheme using the strong coupling between excited atoms and a single-mode cavity field. 相似文献
19.
Hoffman AJ Srinivasan SJ Schmidt S Spietz L Aumentado J Türeci HE Houck AA 《Physical review letters》2011,107(5):053602
Mediated photon-photon interactions are realized in a superconducting coplanar waveguide cavity coupled to a superconducting charge qubit. These nonresonant interactions blockade the transmission of photons through the cavity. This so-called dispersive photon blockade is characterized by measuring the total transmitted power while varying the energy spectrum of the photons incident on the cavity. A staircase with four distinct steps is observed and can be understood in an analogy with electron transport and the Coulomb blockade in quantum dots. This work differs from previous efforts in that the cavity-qubit excitations retain a photonic nature rather than a hybridization of qubit and photon and provides the needed tolerance to disorder for future condensed matter experiments. 相似文献