Deterministic remote preparation of multi-qubit equatorial states through dissipative channels

We investigate the influence of a noisy environment on the remote preparation of the multi-qubit equatorial state, and specifically deduce the final states and fidelities of the remote preparation of the three-qubit and four-qubit equatorial states under diverse types of noisy environments, namely, amplitude damping, bit flip, phase damping, phase flip, bit-phase flip,depolarization, and non-Markov environments. The results show that when the decoherence factors of the front six noises are equal, the influence degrees of phase damped noise, bit flip noise, phase flip noise, and bit-phase flip noise are similar,while the information loss caused by the amplitude damped noise and depolarizing noise is less. In particular, the bit flip noise and depolarizing noise may have more complex effects on the remote state preparation(RSP) schemes depending on the phase information of the target states, even for the ideal cases where the fidelity values are always 1 for specific phase relations. In the non-Markov environment, owing to the back and forth of information between the environment and systems, fidelities exhibit oscillating behavior and the minimum value may stay greater than zero for a long evolutionary time. These results are expected to have potential applications for understanding and avoiding the influence of noise on remote quantum communication and quantum networks.

A new optical field generated as an output of the displaced Fock state in an amplitude dissipative channel

We propose a new optical field and show that such an optical field can be generated as an output of a displaced Fock state in an amplitude dissipative channel. We derive new generating function formulas and binomial formula involving twovariable Hermite polynomials to reach this result. The photon number average in this new optical field is m＋｜α｜^2e^-2κt,which indicates that controlling the photon number can be realized by adjusting the value of m or ｜α｜2 or κ. The time evolution law of displaced Fock state in a thermo reservoir is thus revealed.

Evolution of a two-mode squeezed vacuum in the amplitude dissipative channel

For the first time we derive the dissipating result of an initial two-mode squeezed pure vacuum state passing through a two-mode amplitude dissipative channel described by the direct product of two independent single-mode master equations. Although these two master equations do not mix the two modes （there is no coupling between them）, since the two-mode squeezed state is simultaneously an entangled state, the final state which emerges from passing this channel is a two-mode mixed density operator. The compact expression of the outcoming state is obtained, which manifestly shows that as time evolves, the squeezing effect decreases.

Dissipation of a two-mode squeezed vacuum state in the single-mode amplitude damping channel

We explore how a two-mode squeezed vacuum state sechθeab tanh θ[00） evolves when it undergoes a single- mode amplitude dissipative channel with rate of decay k. We find that in this process not only the squeezing parameter decreases, tanhθ → e-kt tanh θ, but also the second-mode vacuum state evolves into a chaotic state exp{bbln[（1 - e-2kt） tanh2 θ]}. The outcome state is no more a pure state, but an entangled mixed state.

Damping of displaced chaotic light field in amplitude dissipation channel

We explore how a displaced chaotic light (DCL) behaves in an amplitude dissipation channel, and what is its time evolution formula of photon number distribution. With the use of the method of integration within ordered product product of operator (IWOP) and the new binomial theorem involving two-variable Hermite polynomials we obtain the evolution law of DCL in the channel.

Asymptotic dynamics of the alternate degrees of freedom for a two-mode system:An analytically solvable model

The composite systems can be non-uniquely decomposed into parts（subsystems）.Not all decompositions（structures） of a composite system are equally physically relevant.In this paper we answer on theoretical ground why it may be so.We consider a pair of mutually un-coupled modes in the phase space representation that are subjected to the independent quantum amplitude damping channels.By investigating asymptotic dynamics of the degrees of freedom,we find that the environment is responsible for the structures non-equivalence.Only one structure is distinguished by both locality of the environmental influence on its subsystems and a classical-like description.

Spatial relationship between energy dissipation and vortex tubes in channel flow

The spatial relationship between the energy dissipation slabs and the vortex tubes is investigated based on the direct numerical simulation（DNS） of the channel flow. The spatial distance between these two structures is found to be slightly greater than the vortex radius. Comparison of the core areas of the vortex tubes and the dissipation slabs gives a mean ratio of 0.16 for the mean swirling strength and that of 2.89 for the mean dissipation rate. These results verify that in the channel flow the slabs of intense dissipation and the vortex tubes do not coincide in space. Rather they appear in pairs offset with a mean separation of approximately 10η.