共查询到20条相似文献,搜索用时 0 毫秒
1.
P. Chang B. Shao J. Zou 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,57(4):371-377
The dynamics of the entanglement for a solid polariton
system is investigated. The polariton system is a photon-phonon complex and
its time-dependent characteristic function in the Wigner representation for
the system is obtained analytically. It is found that when the photon field
is initially prepared in the squeezed vacuum state, and the phonon in the
thermal state, the polariton system can evolve into a two-mode Gaussian
mixed state. The entanglement between photon and phonon turns out to be
apparently dependent on the squeezing parameter and exhibits a critical
behavior with respect to the temperature. 相似文献
2.
The dynamic evolutions of the discord and entanglement of two atoms immersed in two independent Lorentzian reservoirs at zero and finite temperatures have been investigated by using the time-convolutionless master-equation method.Our results show that,nonzero temperature can induce the entanglement sudden death and accelerate the decays of discord and entanglement.The discord and the entanglement have different robustness for different initial states and their robustness may change under certain conditions.When both the non-Markovian effect and detuning are present simultaneously,due to the memory and feedback effect of non-Markovian reservoirs,the discord and entanglement can be effectively protected even at nonzero temperature by increasing the non-Markovian effect and the detuning. 相似文献
3.
We study the loss of entanglement of a bipartite state subjected to discarding or measurement of one qubit. Examining behavior of different entanglement measures, we find that entanglement of formation, entanglement cost, logarithmic negativity, and one-way distillable entanglement are lockable measures in that they can decrease arbitrarily after measuring one qubit. We prove that any convex and asymptotically noncontinuous measure is lockable. As a consequence, all the convex-roof measures can be locked. The relative entropy of entanglement is shown to be a nonlockable measure. 相似文献
4.
5.
The properties of nuclear matter are studied in the frame of the Brueckner theory. The Brueckner-Hartree-Fock approximation plus two-body density-dependent Skyrme potential which is equivalent to three-body interaction are used. Various modern nucleon-nucleon potentials are used in the framework of the Brueckner-Hartree-Fock approximation, e.g.: CD-Bonn potential, Nijm1 potential, and Reid 93 potential. These modern nucleon-nucleon potentials fit the deuteron properties and are phase shifts equivalent. The equation of state at T = 0, pressure at T = 0, 8, and 12 MeV, free energy at T = 8 and 12 MeV, nuclear matter incompressibility, and the symmetry energy calculation are presented. The hot properties of nuclear matter are calculated using T 2-approximation method at low temperatures. Good agreement is obtained in comparison with previous theoretical estimates and experimental data, especially at low densities. 相似文献
6.
A system of two initially entangled qubits interacting with a bosonic environment is considered. The interaction induces a loss of the initial entanglement of the two qubits, and for specific initial states it causes entanglement sudden death. An investigation of the modifications on the entanglement dynamics by a single pulse control field, performed in the two qubit system, shows that the control field can not only protect entangled states against sudden death but also induce a revival of entanglement in the two qubit system. 相似文献
7.
J. -J. Jiang Y. -J. Liu F. Tang C. -H. Yang 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,81(4):419-424
By using the method of exact diagonalization, we
investigate the quantum correlation measured by quantum discord of the
dimerized spin chain at both zero and finite temperatures. The results
disclose that the quantum discord is robust at any finite parameter α and temperature T, in contrast to entanglement which shows a sudden death
when the parameter α or the temperature T reaches a critical point. At
finite temperature, it is interesting to find that the quantum discord
QD
2i−1, 2i
can increase with temperature T no
matter if the entanglement EoF
2i−1, 2i
exists or
not. The research on the relation between the quantum discord and the
quantum phase transition in the dimerized spin chain indicates that the
transition can be characterized by the first derivation of the quantum
discord at zero and low temperatures. 相似文献
8.
We propose a quantum computing architecture based on the integration of nanomechanical resonators with Josephson-junction phase qubits. The resonators are GHz-frequency, dilatational disk resonators, which couple to the junctions through a piezoelectric interaction. The system is analogous to a collection of tunable few-level atoms (the Josephson junctions) coupled to one or more electromagnetic cavities (the resonators). Our architecture combines desirable features of solid-state and optical approaches and may make quantum computing possible in a scalable, solid-state environment. 相似文献
9.
A. K. Zhuravlev 《Bulletin of the Russian Academy of Sciences: Physics》2014,78(9):894-899
A method is developed for simulating spin-lattice dynamics at finite temperatures for a system of particles with spin-lattice coupling. Thermodynamic equilibrium is ensured by including several additional variables that simulate the thermostat, affect particles, and satisfy supplementary equations of evolution. The results from calculating the heat capacity and magnetization of a Heisenberg ferromagnetic with vibrational degrees of freedom are given to demonstrate the possibilities of the method. 相似文献
10.
Population dynamics of excited atoms in non-Markovian environments at zero and finite temperature 下载免费PDF全文
《中国物理 B》2015,(8)
The population dynamics of a two-atom system, which is in two independent Lorentzian reservoirs or in two independent Ohmic reservoirs respectively, where the reservoirs are at zero temperature or finite temperature, is studied by using the time-convolutionless master-equation method. The influences of the characteristics and temperature of a non-Markovian environment on the population of the excited atoms are analyzed. We find that the population trapping of the excited atoms is related to the characteristics and the temperature of the non-Markovian environment. The results show that, at zero temperature, the two atoms can be effectively trapped in the excited state both in the Lorentzian reservoirs and in the Ohmic reservoirs. At finite temperature, the population of the excited atoms will quickly decay to a nonzero value. 相似文献
11.
《Nuclear Physics A》1986,460(2):201-221
Using the second RPA property that the nuclear intrinsic degrees of freedom (specifically, the quadruples) are invested with bosonic qualities, we describe the nuclear dissipative process as the damping of a collective degree of freedom coupled to a bosonic reservoir at finite temperature. The resulting second RPA master equation within the observed collective subspace agrees exactly in form with the master equation utilized in quantum optics; it describes how a gas of collective RPA phonons relaxes to a Bose-Einstein thermal equilibrium. We further solve this master equation and provide illustrative examples for specific initial conditions. The second RPA approach accounts for quantal fluctuations in addition to the statistical fluctuations, and thus contrasts with the Kramers-Chandrasekhar approach usually utilized in nuclear physics. Furthermore, the second RPA master equation contrasts with the corresponding results of the linear response approach and of the random matrix model. 相似文献
12.
13.
We study the effect of a thermal reservoir on the squeezing transfer and entanglement between two identical harmonic oscillators, caused by a bilinear coupling of the RWA type. We analyze the evolution of the invariant squeezing coefficients of each mode for arbitrary initially factorized mixed states, as well as the separability coefficient based on Simon's criterion for Gaussian states. We show the importance of initial squeezing for the emergence of entanglement and the existence of critical temperatures above which no squeezing transfer or entanglement are possible. 相似文献
14.
15.
The macroscopic quantum entanglement in capacitively
coupled SQUID (superconducting quantum interference device)-based
charge qubits is
investigated theoretically. The entanglement characteristic is discussed by
employing the quantum Rabi oscillations and the concurrence. An
interesting conclusion is obtained, i.e., the magnetic fluxes
Фx1 and Фx2 through the superconducting
loops can adjust the entanglement degree between the qubits. 相似文献
17.
18.
Gauge theories of the Yang–Mills type are the single most important building block of the standard model of particle physics and beyond. They are an integral part of the strong and weak interactions, and in their Abelian version of electromagnetism. Since Yang–Mills theories are gauge theories their elementary particles, the gauge bosons, cannot be described without fixing a gauge. Therefore, to obtain their properties a quantized and gauge-fixed setting is necessary. 相似文献
19.
Munhoz P. P. Semio F. L. 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,59(3):509-519
We theoretically investigate the role of different phases of coupling constants in the dynamics of atoms and two cavity modes,
observing deterministic generation of prototype or hybrid Bell, W, GHZ, and cluster states. Commonly induced dipole-dipole
interactions (far-off resonance) are inhibited between particular pairs of qubits under suitable choice of those phases. We
evaluate the generation fidelities when imperfections such as dissipative environments and time precision errors are considered.
We show violation of local realism for the generated cluster state under such imperfections, even when approaching the weak
coupling regime. 相似文献
20.
A. B. Zorin 《Journal of Experimental and Theoretical Physics》2004,98(6):1250-1261
The Josephson qubit based on a superconducting single charge transistor inserted in a low-inductance superconducting loop is considered. The loop is inductively coupled to a radio-frequency driven tank circuit enabling the readout of the qubit states by measuring the effective Josephson inductance of the transistor. The effect of qubit dephasing and relaxation due to electric and magnetic control lines, as well as the measuring system, is evaluated. Recommendations for qubit operation with minimum decoherence are given. 相似文献