We discuss the rotational cooling of diatomic molecules in a Bose-Einstein
condensate (BEC) of ultra-cold atoms by emission of phonons with orbital
angular momentum. Despite the superfluidity of the BEC there is no frictionless
rotation for typical molecules since the dominant cooling occurs via emission
of particle-like phonons. Only for macro-dimers, whose size becomes comparable
or larger than the condensate healing length, a Landau-like, critical angular

In the last decades unprecedented progress in the manipulation of spin
angular momentum (SAM) and orbital angular momentum (OAM) of light has been
achieved, enabling a number of applications ranging from classical and quantum
communication, to optical microscopy and super-resolution imaging. Metasurfaces
are artificially engineered 2D metamaterials with designed subwavelength-size
building blocks, which allow precise control of optical fields with
unparalleled flexibility and performance. The reduced dimensionality of optical

We propose a practical protocol to generate and observe a non-Abelian
geometric phase using a periodically driven Raman process in the hyperfne
ground state manifold of atoms in a dilute ultracold gas. Our analysis is based
upon recent developments and application of Floquet theory to periodically
driven quantum systems. The simulation results show the non-Abelian gauge
transformation and the non-commuting property of the SU(2) transformation
operators. Based on these results, we propose a possible experimental

Number state filtered coherent states are a class of nonclassical states
obtained by removing one or more number states from a coherent state. Phase
sensitivity of an interferometer is enhanced if these nonclassical states are
used as input states. The optimal phase sensitivity, which is related to the
quantum Cramer-Rao bound (QCRB) for the input state, improves beyond the
standard quantum limit. It is argued that removal of more than one suitable
number state leads to better phase sensitivity. As an important limiting case

Via the hierarchy of correlations, we study the Mott insulator phase of the
Fermi-Hubbard model in the limit of strong interactions and derive a quantum
Boltzmann equation describing its relaxation dynamics. In stark contrast to the
weakly interacting case, we find that the scattering cross sections strongly
depend on the momenta of the colliding quasi-particles and holes. Therefore,
the relaxation towards equilibrium crucially depends on the spectrum of

As with any quantum computing platform, semiconductor quantum dot devices
require sophisticated hardware and controls for operation. The increasing
complexity of quantum dot devices necessitates the advancement of automated
control software and image recognition techniques for rapidly evaluating charge
stability diagrams. We use an image analysis toolbox developed in Python to
automate the calibration of virtual gates, a process that previously involved a
large amount of user intervention. Moreover, we show that straightforward

We study entanglement of spin degrees of freedom with continuous one in
supersymmetric (SUSY) quantum mechanics. Concurrence is determined by mean
value of spin and is calculated explicitly for SUSY states. We show that
eigenstates of supercharges are maximally entangled. As an example the
entanglement of atom state with photon state and SUSY in Jaynes-Cummings model
are considered.

Author(s): Eric Boyers, Mohit Pandey, David K. Campbell, Anatoli Polkovnikov, Dries Sels, and Alexander O. Sushkov
Adiabatic evolution is a common strategy for manipulating quantum states and has been employed in diverse fields such as quantum simulation, computation, and annealing. However, adiabatic evolution is inherently slow and therefore susceptible to decoherence. Existing methods for speeding up adiabati...
[Phys. Rev. A 100, 012341] Published Thu Jul 25, 2019

Author(s): Yafei Wen, Pai Zhou, Zhongxiao Xu, Liang Yuan, Haoyi Zhang, Shengzhi Wang, Long Tian, Shujing Li, and Hai Wang
A source that can generate atom-photon quantum correlations or entanglement based on a quantum memory is a basic building block of quantum repeaters (QRs). To achieve high entanglement generation rates in ensemble-based QRs, spatial-, temporal-, and spectral-multimode memories are needed. Previous t...
[Phys. Rev. A 100, 012342] Published Thu Jul 25, 2019

Author(s): Jia-Qi Zhou, Ling Cai, Qi-Ping Su, and Chui-Ping Yang
Implementation of a discrete-time quantum walk (DTQW) with superconducting qubits is difficult since on-chip superconducting qubits cannot hop between lattice sites. We propose an efficient protocol for the implementation of DTQW in circuit quantum electrodynamics (QED), in which only $N+1$ qutrits,...
[Phys. Rev. A 100, 012343] Published Thu Jul 25, 2019