Quantum entanglement may have various origins ranging from solely
interaction-driven quantum correlations to single-particle effects. Here, we
explore the dependence of entanglement on time-dependent single-particle basis
transformations in fermionic quantum many-body systems, thus aiming at
isolating single-particle sources of entanglement growth in quench dynamics.
Using exact diagonalization methods, for paradigmatic non-integrable models we
compare to the standard real space cut various physically motivated

The effects of an impurity plaquette on the thermal quantum correlations
measurement by the concurrence, on the quantum coherence quantified by the
recently proposed $l_{1}$-norm of coherence and on the quantum teleportation in
a Ising-$XXZ$ diamond chain are discussed. Such an impurity is formed by the
XXZ interaction between the interstitial Heisenberg dimers and the
nearest-neighbor Ising coupling between the nodal and interstitial spins. All
the interaction parameters are different from those of the rest of the chain.

Fluctuation dissipation theorems connect the linear response of a physical
system to a perturbation to the steady-state correlation functions. Until now,
most of these theorems have been derived for finite-dimensional systems.
However, many relevant physical processes are described by systems of infinite
dimension in the Gaussian regime. In this work, we find a linear response
theory for quantum Gaussian systems subject to time dependent Gaussian
channels. In particular, we establish a fluctuation dissipation theorem for the

We apply the Wigner function formalism from quantum optics via two
approaches, Wootters' discrete Wigner function and the generalized Wigner
function, to detect quantum phase transitions in critical spin-$\tfrac{1}{2}$
systems. We develop a general formula relating the phase space techniques and
the thermodynamical quantities of spin models, which we apply to single,
bipartite and multi-partite systems governed by the $XY$ and the $XXZ$ models.
Our approach allows us to introduce a novel way to represent, detect, and

We make use of a custom-designed cryo-CMOS multiplexer (MUX) to enable
multiple quantum devices to be characterized in a single cool-down of a
dilution refrigerator. Combined with a packaging approach that integrates
cryo-CMOS chips and a hot-swappable, parallel device test platform, we describe
how this setup takes a standard wiring configuration as input and expands the
capability for batch-characterization of quantum devices at milli-Kelvin
temperatures and high magnetic fields. The architecture of the cryo-CMOS

Author(s): Yu-Hao Deng, Hui Wang, Xing Ding, Z.-C. Duan, Jian Qin, M.-C. Chen, Yu He, Yu-Ming He, Jin-Peng Li, Yu-Huai Li, Li-Chao Peng, E. S. Matekole, Tim Byrnes, C. Schneider, M. Kamp, Da-Wei Wang, Jonathan P. Dowling, Sven Höfling, Chao-Yang Lu, Marlan O. Scully, and Jian-Wei Pan
Researchers witness quantum interference and entanglement between photons from sources 150 million km apart—the Sun and a quantum dot in their lab.
[Phys. Rev. Lett. 123, 080401] Published Wed Aug 21, 2019

Author(s): Antoine Tilloy and Thomas M. Stace
Spontaneous wave-function collapse models, like continuous spontaneous localization, are designed to suppress macroscopic superpositions while preserving microscopic quantum phenomena. An observable consequence of collapse models is spontaneous heating of massive objects. We calculate the collapse-i...
[Phys. Rev. Lett. 123, 080402] Published Wed Aug 21, 2019

Author(s): Chungwei Lin, Yebin Wang, Grigory Kolesov, and Uroš Kalabić
Grover's algorithm is one of the most famous algorithms which explicitly demonstrates how the quantum nature can be utilized to accelerate the searching process. In this work, Grover's quantum search problem is mapped to a time-optimal control problem. Resorting to Pontryagin's minimum principle, we...
[Phys. Rev. A 100, 022327] Published Wed Aug 21, 2019

Author(s): Denis Bernard and Tony Jin
We present the solution to a model of fermions hopping between neighboring sites on a line with random Brownian amplitudes and open boundary conditions driving the system out of equilibrium. The average dynamics reduces to that of the symmetric simple exclusion process. However, the full distributio...
[Phys. Rev. Lett. 123, 080601] Published Wed Aug 21, 2019

The intuition that we have about entropy -- coming largely from the Boltzmann
entropy -- is that the maximum entropy state is very close to the equilibrium
state, while low entropy is associated with highly non-equilibrium states. It
this paper, we investigate two well-developed definitions of entropy relevant
for describing the dynamics of isolated quantum systems, and ask if they lead
to this same intuition, by studying their extreme fluctuations. We choose