arXiv subjects

Lin Xia

Publications and source records attributed to Lin Xia.

8 recordsLinked to original sources

arXiv2026

Increase of Magnetic Trap Loading Efficiency for $^{39}\mathrm{K}$ Bose--Einstein Condensation Experiments

During the experimental sequence, a large atom number is important for the creation of high-quality Bose--Einstein condensates. We report an experimental increase of about 15% in magnetic-trap (MT) loading efficiency by optimizing the MT loading process. The loading time is much shorter than the lifetime of the atoms in the MT, which means atom loss during loading due to the finite trap lifetime can be neglected. We obtain an almost pure $^{39}\mathrm{K}$ condensate with $1.2\times10^{5}$ atoms after evaporative cooling in our optical trap.

cond-mat.quant-gas↗

arXiv2018

Detecting the entanglement of vortices in ultracold bosons with artificial gauge fields

The entanglement of vortices in a two-dimensional Bose-Hubbard model with artificial gauge fields is investigated using the exact diagonalization techniques. We propose an effective Hamiltonian for the spin-spin interactions between vortices responsible for this entanglement, and show that the entanglement can be detected through the quantum interference of the bosons in the vortex centers achieved using the Raman coupling and the quantum gas microscope. The strong bosonic coherence between the vortex centers originates from the charge-density wave order in the vortex core. It is robust against the varying of the pinning strength for the vortices to a wide range, and the coherent bosons can be viewed as a qubit stored in the ground state of the system. Our proposal provides a feasible scheme of quantum memory for storing qubits useful in quantum computation.

quant-ph↗

arXiv2018

Energy-dependent 3-body loss in 1D Bose gases

We study the loss of atoms in quantum Newton's cradles (QNCs) with a range of average energies and transverse confinements. We find that the three-body collision rate in one-dimension is strongly energy dependent, as predicted by a strictly 1D theory. We adapt the theory to atoms in waveguides, then using detailed momentum measurements to infer all the collisions that occur, we compare the observed loss to the adapted theory and find that they agree well.

physics.atom-ph↗

arXiv2014

Quantum distillation and confinement of vacancies in a doublon sea

Ultracold atomic gases have revolutionized the study of non-equilibrium dynamics in quantum many-body systems. Many counterintuitive non-equilibrium effects have been observed, such as suppressed thermalization in a one-dimensional (1D) gas, the formation of repulsive self-bound dimers, and identical behaviors for attractive and repulsive interactions. Here, we observe the expansion of a bundle of ultracold 1D Bose gases in a flat-bottomed optical lattice potential. By combining in situ measurements with photoassociation, we follow the spatial dynamics of singly, doubly, and triply occupied lattice sites. The system sheds interaction energy by dissolving some doublons and triplons. Some singlons quantum distill out of the doublon center, while others remain confined. Our Gutzwiller mean-field model captures these experimental features in a physically clear way. These experiments might be used to study thermalization in systems with particle losses or the evolution of quantum entanglement, or if applied to fermions, to prepare very low entropy states.

cond-mat.quant-gas↗

arXiv2008

The inherent fluctuations of the pulsed atom laser in F=2 manifold of 87Rb atoms

We have observed the intensity fluctuations of the F=2 87Rb atom laser at low output coupling rate. Theoretically, we find that the atom loss of the condensate due to the output of atom laser leads to fluctuations of the laser pulses, which is inherent in all state changing out-coupling such as rf and Raman. Another reason leading to large fluctuations is the interference of output pulses.

physics.atom-ph↗

arXiv2008

Resonant sequential scattering in two-frequency-pumping superradiance from a Bose-Einstein condensate

We study sequential scattering in superradiance from a Bose-Einstein condensate pumped by a two-frequency laser beam. We find that the distribution of atomic side modes presents highly different patterns for various frequency difference between the two pump components. A novel distribution is observed, with a frequency difference of eight times the recoil frequency. These observations reveal that the frequency overlap between the end-fire modes related to different side modes plays an essential role in the dynamics of sequential superradiant scattering. The numerical results from a semiclassical model qualitatively agree with our observations.

quant-ph↗

arXiv2006

Manipulation of the quantum state by Majorana transition in spinor Bose-Einstein condensates

Manipulation of the quantum state by the Majorana transition in spinor BEC system has been realized by altering the rotation frequency of the magnetic field's direction. This kind of manipulation method has no limitation on the transition speed in principle and the system is well closed, which provides a new and superior tool to manipulate quantum states. Using this methord on pulsed atom laser, multicomponent spinor atom laser is generated. We demonstrate that the experiment results are agreed with the theoretical predication.

quant-ph↗

arXiv2005

The Population Oscillation of Multicomponent Spinor Bose-Einstein Condensate Induced by Nonadiabatic Transitions

The generation of the population oscillation of the multicomponent spinor Bose-Einstein condensate is demonstrated in this paper. We observe and examine the nonsynchronous decreasing processes of the magnetic fields generated between quadrupole coils and Ioffe coils during the switch-off of the quadrupole-Ioffe-configuration trap, which is considered to induce a nonadiabatic transition. Starting from the two-level Schrödinger equation, we have done some numerical fitting and derived an analytical expression identical to the results of E. Majorana and C. Zener, of which both the results well match the experimental data.

cond-mat.other↗