In quantum information, lifting is a procedure employed to derive a Bell
inequality applicable in a more complicated Bell scenario from an existing one.
It is known that the procedure of lifting considered by Pironio [J. Math. Phys.
A 46, 062112 (2005)] preserves the facet-defining property of a Bell
inequality. Here, we perform a complementary investigation showing that the
maximal value of a lifted Bell inequality is preserved for both the set of
non-signaling correlations and quantum correlations. Moreover, the optimal

Evidence for Bell's nonlocality is so far mainly restricted to microscopic
systems, where the elements of reality that are negated predetermine results of
measurements to within one spin unit. Any observed nonlocal effect (or lack of
classical predetermination) is then limited to no more than the difference of a
single photon or electron being detected or not (at a given detector). In this
paper, we analyze experiments that report Einstein-Podolsky-Rosen (EPR)
steering form of nonlocality for mesoscopic photonic or Bose-Einstein

Entangling operations are among the most important primitive gates employed
in quantum computing and it is crucial to ensure high-fidelity implementations
as systems are scaled up. We experimentally realize and characterize a simple
scheme to minimize errors in entangling operations related to the residual
excitation of mediating bosonic oscillator modes that both improves
gate-robustness and provides scaling benefits in larger systems. The technique
employs discrete phase shifts in the control field driving the gate operation,

We investigate how topological entanglement of Chern-Simons theory is
captured in a string theoretic realization. Our explorations are motivated by a
desire to understand how quantum entanglement of low energy open string degrees
of freedom is encoded in string theory (beyond the oft discussed classical
gravity limit). Concretely, we realize the Chern-Simons theory as the
worldvolume dynamics of topological D-branes in the topological A-model string
theory on a Calabi-Yau target. Via the open/closed topological string duality

The monopole for the geometric curvature is studied for non-Hermitian
systems. We find that the monopole contains not only the exceptional points but
also branch cuts. As the mathematical choice of branch cut in the complex plane
is rather arbitrary, the monopole changes with the branch-cut choice. Despite
this branch-cut dependence, our monopole is invariant under the
$GL(l,\mathbb{C})$ gauge transformation that is inherent in non-Hermitian
systems. Although our results are generic, they are presented in the context of

State preparation protocols ideally require as minimal operations as
possible, in order to be implemented in near-term, potentially noisy quantum
devices. Motivated by long range interactions (LRIs) intrinsic to many
present-day experimental platforms (trapped ions, Rydberg atom arrays, etc.),
we investigate the efficacy of variationally simulating non-trivial quantum
states using the Variational Quantum-Classical Simulation (VQCS) protocol
explored recently in [SciPost Phys. 6, 029 (2019)], in the presence of LRIs. We

In this article we provide a method for fully quantum generative training of
quantum Boltzmann machines with both visible and hidden units while using
quantum relative entropy as an objective. This is significant because prior
methods were not able to do so due to mathematical challenges posed by the
gradient evaluation. We present two novel methods for solving this problem. The
first proposal addresses it, for a class of restricted quantum Boltzmann
machines with mutually commuting Hamiltonians on the hidden units, by using a

Quantum fluctuations associated with the ground state of a system exist as a
consequence of Heisenberg's uncertainty principle. These fluctuating fields
manifest themselves indirectly through their influence on matter which has been
extensively studied by considering e.g. the Casimir and Casimir-Polder force.
More recently, these ground state fluctuations have been measured directly
using nonlinear crystals by means of electro-optical sampling. Despite their
common origin, these direct versus indirect evidence of ground-state

Using criteria based on superselection rules, we analyze the quantum
correlations between the two condensate modes of the Bose-Einstein condensate
interferometer of Egorov et al. [Phys. Rev. A 84, 021605 (2011)]. In order to
determine the two-mode correlations, we develop a multi-mode theory that
describes the dynamics of the condensate atoms and the thermal fraction through
the interferometer sequence, in agreement with the experimentally measured
fringe visibility. We thus present experimental evidence for two-mode entangled

A comprehensive study of three-photon electromagnetically-induced
transparency (EIT) and absorption (EIA) on the rubidium cascade $5S_{1/2}
\rightarrow 5P_{3/2}$ (laser wavelength 780~nm), $5P_{3/2} \rightarrow
5D_{5/2}$ (776~nm), and $5D_{5/2}\rightarrow 28F_{7/2}$ (1260~nm) is performed.
The 780-nm probe and 776-nm dressing beams are counter-aligned through a Rb
room-temperature vapor cell, and the 1260-nm coupler beam is co- or
counter-aligned with the probe beam. Several cases of EIT and EIA, measured