Cold Atoms For Testing Quantum Mechanics and Parity Violation In Gravitation

Detecting topological exceptional points in a parity-time symmetric system with cold atoms

We reveal a novel topological property of the exceptional points in a two-level parity-time symmetric system and then propose a scheme to detect the topological exceptional points in the system, which is embedded in a larger Hilbert space constructed by a four-level cold atomic system. We show that a tunable parameter in the presented system for simulating the non-Hermitian Hamiltonian can be tuned to swept the eigenstates through the exceptional points in parameter space. The non-trivial Berry phases of the eigenstates obtained in this loop from the exceptional points can be measured by the a…

Gravitational field measurement with an equilibrium ensemble of cold atoms

A new approach to the measurement of gravitational fields with an equilibrium ensemble of ultra-cold alkali atoms confined in a cell of volume $V$ is investigated. The proposed model of the gravitational sensor is based on a variation of the density profile of the ensemble due to changing of the gravitational field. For measurement the atomic density variations of the ensemble the electromagnetically induced transparency method is used.

冷原子狄拉克晶格中Floquet工程化的奇偶反常阶梯

Floquet-Engineered Parity Anomaly Staircase in a Cold Atom Dirac Lattice

提出利用Floquet工程在二维π通量晶格中实现奇偶反常启发的反常霍尔阶梯，通过选择性地占据不同狄拉克扇区的贝里曲率贡献，得到阶梯状霍尔响应。

Thermodynamics of Quantum Ultra-cold Neutron Gas under Gravity of The Earth

The stored ultra-cold neutrons have been developed. A high density ultra-cold neutron gas has been recently produced by using the nuclear spallation method. We investigate the thermodynamic properties of the quantum ultra-cold neutron gas in the Earth's gravitational field. We find that the quantum effects increase temperature dependence of the chemical potential and the internal energy in the low temperature region. The density distribution of quantum ultra-cold neutron gas is modified by the Earth's gravitational field.

The quantum ultra-cold neutron gas trapped in the two-dimensional harmonic oscillator potential on the Earth's gravitational field

In our previous paper, we have investigated the thermodynamics of the quantum ultra-cold neutron gas trapped in the two-dimensional square-well potential on the Earth's gravitational field. We have pointed out that they have strong dependence on the shape of the trapping potential. In the present paper, we estimate the Fermi energy and the density distribution of the Fermi gas with two-dimensional harmonic oscillator potential, instead of the square-well potential. Then we discuss them in terms of the Fermi energy and the density distribution as compared with both of cases.

Probing neutron's electric neutrality with Ramsey Spectroscopy of gravitational quantum states of ultra-cold neutrons

We propose to test the electric neutrality of neutrons by a new technique using the spectroscopy of quantum states of ultra-cold neutrons in the gravity potential above a vertical mirror. The new technique is an application of Ramsey's method of separated oscillating fields to neutron's quantum states in the gravity potential of the earth. In the presence of an electric field E parallel or antiparallel to the direction of the acceleration of the earth g, the energy of the quantum states changes due to an additional electrostatic potential if a neutron carries a non-vanishing charge. In the lon…