Mo-Lin Ge

Nonclassical effect in the MIT output coupler for the Bose–Einstein condensate

Abstract A quantum dynamical theory for output coupler of the trapped Bose–Einstein condensate is presented under no rotating wave approximation (RWA) based on the MIT experiment (Phys. Rev. Lett. 78 (1997) 582) for the atom laser. We show that the nonclassical properties, such as sub-Poisson distribution and quadrature squeezing effect, can exist in the outcoupled atomic pulse as time evolves, which indicates an interesting optical control on quantum statistics of the atom laser through varying the strength of the input light.

Exact solutions for the time-dependent Hamiltonian in high-dimension and many-body problem

Abstract The method of Ray is used to solve the high-dimensional and many-body time-dependent problems. Exact solutions of the models including Calogero model in time-dependent harmonic potential are studied by using this method.

Non-adiabatic Berry's phase in many-body and high-dimensional system

Abstract A series of solvable time-dependent models about high-dimensional and many-body systems are given, which include the Calogero model trapped in a time-dependent harmonic well. If these models evolve periodically with time, a non-adiabatic Berrys phase in these models can be obtained.

THE NON-ADIABATIC BERRY PHASE IN TWO DIMENSIONS : THE CALOGERO MODEL TRAPPED IN A TIME-DEPENDENT EXTERNAL FIELD

The two-dimensional Calogero model in a time-independent external magnetic field is extended to the time-dependent case which can be solved exactly. Both the invariant operator and the eigenstate are obtained. For the periodical time-dependent case, the non-adiabatic Berry phase is also presented.

Free energy and Green function for the multi-coupled spin system

The free energy and Green function of the multi-coupled spin chain in low-energy theory are given by using the functional bosonization method. We deduce that 2m coupled spinless chains (m = 0,1,2,...), by using a series of unitary transformations, can be reduced to some uncoupled chains, but for other numbers of coupled spinless chains we need to solve a series of inverse matrices generally; for either case, the system can be formally separated into the charge and spin parts.

Electric current and conductance in a chain of quantum dots

By using the non-equilibrium Green function method, we give the current flowing in a chain of quantum dots exactly. The result coincides with the Landauer formula. Finally, the conductance of the system is given in the linear approximation.

Thermal conductance and Lorentz number for fractional exclusion particle

The thermal conductance and the Lorentz number for fractional exclusion particles are investigated in the ballistic regime. By using Ramo-Shockley theory, it is shown that the thermal conductance is independent of the statistical properties under the particle complete degeneracy condition, but the Lorentz number is not, and they are both independent of the transport material.

U(1) SYMMETRY IN YANGIAN AND MASSLESS THIRRING MODEL

Yangian Y(sl(2)) constructed by fermionic field operators is extended to the q-deformed case which can be realized in the massless Thirring model. This leads to local U(1) gauge-invariance of Y(sl(2)) and evolution of the double-time Green function in q-statistics.