All

Author(s): Ivan M. Khaymovich, Masudul Haque, and Paul A. McClarty
The eigenstate thermalization hypothesis (ETH) is one of the cornerstones of contemporary quantum statistical mechanics. The extent to which ETH holds for nonlocal operators is an open question that we partially address in this Letter. We report on the construction of highly nonlocal operators, behe...
[Phys. Rev. Lett. 122, 070601] Published Tue Feb 19, 2019

Author(s): Xing-Yan Chen and Zhang-qi Yin
We propose a scheme to realize the controlled-phase gates between nitrogen-vacancy (NV) centers in an optically trapped nanodiamond, through a uniform magnetic field-induced coupling between the NV centers and the torsional mode of the levitated nanodiamond. The gates are insensitive to the thermal ...
[Phys. Rev. A 99, 022319] Published Tue Feb 19, 2019

Quantum channel simulations constructing probability tensors for biological multi-taxa in
phylogenetics are proposed. These are given in terms of positive trace preserving maps (quantum
channels), operating on quantum density matrices, using evolving systems of quantum walks with
multiple walkers. Simulation of a variety of standard phylogenetic branching models, applying on
trees of various topologies, is constructed using appropriate decoherent quantum circuits. For the

We use a tangent method approach to obtain the arctic curve in a model of non-intersecting lattice
paths within the first quadrant, including a q -dependent weight associated with the area delimited
by the paths. Our model is characterized by an arbitrary sequence of starting points along the
positive horizontal axis, whose distribution involves an arbitrary piecewise differentiable
function. We give an explicit expression for the arctic curve in terms of this arbitrary function

Discriminating between quantum states is a fundamental problem in quantum
information protocols. The optimum approach saturates the Helstrom bound, which
quantifies the unavoidable error probability of mistaking one state for
another. Computing the error probability directly requires complete knowledge
and diagonalization of the density matrices describing these states. Both of
these fundamental requirements become impractically difficult to obtain as the
dimension of the states grow large. In this article, we analyze quantum

In fundamental theories that accounts for quantum gravitational effects, the
spacetime causal structure is expected to be quantum uncertain. Previous
studies of quantum causal structure focused on finite-dimensional systems. Here
we present an algebraic framework that incorporates both finite- and
infinite-dimensional systems including quantum fields. Thanks to the absence of
a definite spacetime causal structure, Lagrangian quantum field theories can be

Schr\"odinger's famous Gedankenexperiment has inspired multiple generations
of physicists to think about apparent paradoxes that arise when the logic of
quantum physics is applied to macroscopic objects. The development of quantum
technologies enabled us to produce physical analogues of Schr\"odinger's cats,
such as superpositions of macroscopically distinct states as well as entangled
states of microscopic and macroscopic entities. Here we take one step further

In quantum physics the term `contextual' can be used in more than one way.
One usage, here called `Bell contextual' since the idea goes back to Bell, is
that if $A$, $B$ and $C$ are three quantum observables, with $A$ compatible
(i.e., commuting) with $B$ and also with $C$, whereas $B$ and $C$ are
incompatible, a measurement of $A$ might yield a different result (indicating
that quantum mechanics is contextual) depending upon whether $A$ is measured
along with $B$ (the $\{A,B\}$ context) or with $C$ (the $\{A,C\}$ context). An

In contrast with classical physics, in quantum physics some sets of
measurements are incompatible in the sense that they can not be performed
simultaneously. Among other applications, incompatibility allows for
contextuality and Bell nonlocality. This makes of crucial importance developing
tools for certifying whether a set of measurements posses a certain structure
of incompatibility. Here we show that, for quantum or nonsignaling models, if
the measurements employed in a Bell test satisfy a given type of compatibility,

A quantum vortex dipole, comprised of a closely bound pair of vortices of
equal strength with opposite circulation, is a spatially localized travelling
excitation of a planar superfluid that carries linear momentum, suggesting a
possible analogy with ray optics. We investigate numerically and analytically
the motion of a quantum vortex dipole incident upon a step-change in the
background superfluid density of an otherwise uniform two-dimensional
Bose-Einstein condensate. Due to the conservation of fluid momentum and energy,