Ji-Suo Wang

Coulomb blockade and quantum fluctuations of mesoscopic inductance coupling circuit

The quantum theory for a mesoscopic inductance coupling circuit in accord with the discreteness of electric charges is developed. The finite-difference Schrodinger equation of the coupling circuit has been obtained. The results show that the Coulomb blockade will appear in the circuit and there exist quantum fluctuations of currents in the ground state of the system, and the quantum fluctuations in each component circuit are correlated

Quantum fluctuations of a non-dissipative mesoscopic inductance coupling circuit in a displaced squeezed Fock state

In this Letter, starting from the classical equation of motion for a mesoscopic inductance coupling circuit, the quantum fluctuations of charge and current of the mesoscopic inductance coupling circuit in a displaced squeezed Fock state an investigated, it is found that the quantum fluctuations of charge and current in each component circuit depend on the device of two circuits and squeezing parameters, while the fluctuations do not depend on displacement parameters

Nonclassical properties of even and odd generalized coherent states for an isotonic oscillator

We used the numerical method to study nonclassical properties of the even and odd generalized coherent states and superposition states of generalized coherent states for an isotonic oscillator. The following was shown. (1) The quantum statistical properties of the even and odd generalized coherent states are very different from those of the usual even and odd coherent states, and the Nth-order (N = 2m + 1, m = 0, 1, 2,...) squeezing and sub-Poisson distribution appear alternately for both the even and odd generalized coherent states in some ranges of z = \beta\(2) The weaker the isotonic oscillator potential, the narrower the ranges. (2) The superposition states of generalized coherent states may exhibit the Nth-order squeezing effect too, and this kind of higher-order squeezing effect appears periodically.

Quantum Fluctuations in a Mesoscopic Inductance Coupling Circuit

Starting from the equation of motion of a mesoscopic inductance coupling circuit,the quantum fluctuations of charge and current in the circuit are investigated inboth the eigenstates of the system and the squeezed vacuum state. The resultsshow that there exist quantum fluctuations of the charge and current in bothcases, and the fluctuations in each component circuit are connected.

Probabilistic exact deletion of copies of two non-orthogonal states

We show that each of two copies of two non-orthogonal states randomly selected from a certain set {\psi(1)),\psi(2)>} can be probabilistically deleted by a unitary evolution together with a measurement. We derive an inequality on success probabilities and find their maximums only depend on the overlap of two input states

Phase Properties of New Even and Odd Nonlinear Coherent States

Using the Pegg–Barnett formalism of phase operator, we obtain phase probability distributions of new even and odd nonlinear coherent states. It is shown that the distributions for the states are rather different, and unlike the case of ordinary even and odd coherent states the Pegg–Barnett distribution clearly reflects the different character of quantum interference in the case of the new even and odd coherent states.

Quantum no-deletion theorem for entangled states

We demonstrate that there are no physical means for deleting an unknown entangled state against its copy in either pure or mixed state case

Quantum statistical properties of orthonormalized eigenstates of the operator (â f (n̂))k

The completeness of the k orthonormalized eigenstates of the operator (âf())k (k≥3) is investigated. We introduce a new kind of higher-order squeezing and an antibunching. The properties of the Mth-order squeezing and the antibunching effect of the k states are studied. The result shows that these states may form a complete Hilbert space, and the Mth-order (M = (n + 1/2)k; n = 0,1,...) squeezing effects exist in all of the k states when k is even. There is an antibunching effect in all of the states. An alternative method for constructing the k states is proposed, and the result shows that all of them can be generated by linear superposition of the time-dependent nonlinear coherent states at different instants.

Quantum Statistical Properties of k-Quantum Nonlinear Coherent States

In our preceding work, a class of k-quantum nonlinear coherent states, i.e., the k eigenstates of the powers (B) over cap (k) (k greater than or equal to 3) of the annihilation operator (B) over cap = (a) over cap1/f((N) over cap) of f-oscillators, are introduced. In this paper, we introduce a new kind of higher-order squeezing and an antibunching effect. The quantum statistical properties of the k states are studied. The result shows that the M-th order [M = (n + 1/2)k; n = 0, 1,...] squeezing effects exist in all of the k states when k is even. There is the antibunching effect in all of the k states.

Probabilistic comparing and sorting non-orthogonal quantum states

We show that arbitrary two non-orthogonal quantum states randomly selected from a certain set {\psi(i)>, \psij>} can be compared with certain success probabilities by a general unitary-reduction operation; arbitrary permutation of n individual non-orthogonal states randomly selected from a certain set S = {\psi(1)>,\psi(2)>,...,\psi(n)>} can be probabilistically sorted into some specified order under certain condition. We also derive the conditions determining the best possible comparing or sorting efficiencies