# All

## A tangent method derivation of the arctic curve for q -weighted paths with arbitrary starting points

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

## The maximum advantage of quantum illumination. (arXiv:1902.05587v1 [quant-ph])

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

## Causally neutral quantum physics. (arXiv:1902.05837v1 [quant-ph])

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

## Entanglement of macroscopically distinct states of light. (arXiv:1811.01041v3 [quant-ph] UPDATED)

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

## Quantum Measurements and Contextuality. (arXiv:1902.05633v1 [quant-ph])

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

## Device-independent tests of structures of measurement incompatibility. (arXiv:1902.05841v1 [quant-ph])

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,

## Snell's Law for a vortex dipole in a Bose-Einstein condensate. (arXiv:1811.02110v2 [cond-mat.quant-gas] UPDATED)

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,

## A quantum compiler for qudits of prime dimension greater than 3. (arXiv:1902.05634v1 [quant-ph])

Prevailing proposals for the first generation of quantum computers make use
of 2-level systems, or qubits, as the fundamental unit of quantum information.
However, recent innovations in quantum error correction and magic state
distillation protocols demonstrate that there are advantages of using d-level
quantum systems, known as \emph{qudits}, over the qubit analogues. When
designing a quantum architecture, it is crucial to consider protocols for
compilation, the optimal conversion of high-level instructions used by

## Non-Local Parity Measurements and the Quantum Pigeonhole Effect. (arXiv:1902.05854v1 [quant-ph])

The pigeonhole principle upholds the idea that by ascribing to three
different particles either one of two properties, we necessarily end up in a
situation when at least two of the particles have the same property. In quantum
physics, this principle is violated in experiments involving postselection of
the particles in appropriately-chosen states. Here, we give two explicit
constructions using standard gates and measurements that illustrate this fact.
Intriguingly, the procedures described are manifestly non-local, which

## Parity anomaly laser. (arXiv:1811.06300v2 [physics.optics] UPDATED)

We propose a novel supersymmetry-inspired scheme for achieving robust single
mode lasing in arrays of coupled microcavities, based on factorizing a given
array Hamiltonian into its "supercharge" partner array. Pumping a single
sublattice of the partner array preferentially induces lasing of an unpaired
zero mode. A chiral symmetry protects the zero mode similar to 1D topological
arrays, but it need not be localized to domain walls or edges. We demonstrate