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Author(s): F. E. S. Steinhoff, C. Ritz, N. I. Miklin, and O. Gühne
We generalize the class of hypergraph states to multipartite systems of qudits, by means of constructions based on the d-dimensional Pauli group and its normalizer. For simple hypergraphs, the different equivalence classes under local operations are shown to be governed by a greatest-common-divisor …
[Phys. Rev. A 95, 052340] Published Mon May 22, 2017

Lidar is a well known optical technology for measuring a target's range and
radial velocity. We describe two lidar systems that use entanglement between
transmitted signals and retained idlers to obtain significant quantum
enhancements in simultaneous measurement of these parameters. The first
entanglement-enhanced lidar circumvents the Arthurs-Kelly uncertainty relation
for simultaneous measurement of range and radial velocity from detection of a
single photon returned from the target. This performance presumes there is no

Single photon emitters with narrow linewidths are highly sought after for
applications in quantum information processing and quantum communications. In
this letter, we report on a bright, highly polarized near infrared single
photon emitter embedded in diamond nanocrystals with a narrow, sub GHz optical
linewidths at 10K. The observed zero phonon line at ~ 780 nm is optically
stable under low power resonant excitation and blue shifts as the excitation

Recent progress in characterization for gapped quantum phases has also
triggered the search of universal resource for quantum computation in symmetric
gapped phases. Prior works in one dimension suggest that it is a feature more
common than previously thought that nontrivial 1D symmetry-protected
topological (SPT) phases provide quantum computational power characterized by
the algebraic structure defining these phases. Progress in two and higher
dimensions so far has been limited to special fixed points in SPT phases. Here

Quantum walks and random walks bear similarities and divergences. One of the
most remarkable disparities affects the probability of finding the particle at
a given location: typically, almost a flat function in the first case and a
bell-shaped one in the second case. Here I show how one can impose any desired
stochastic behavior (compatible with the continuity equation for the
probability function) on both systems by the appropriate choice of time- and

Single atoms form a model system for understanding the limits of single
photon detection. Here, we develop a non-Markov theory of single-photon
absorption by a two-level atom to place limits on the transduction time. We
show the existence of a finite rise time in the probability of excitation of
the atom during the absorption event which is infinitely fast in previous
Markov theories. This rise time is governed by the bandwidth of the atom-field
interaction spectrum and leads to a fundamental jitter in time-stamping the

By applying invariant-based inverse engineering in the small-oscillations
regime, we design the time dependence of the control parameters of an overhead
crane (trolley displacement and rope length), to transport a load between two
positions at different heights with minimal final energy excitation for
arbitrary initial conditions. The analogies between ion transport in
multisegmented traps or neutral atom transport in moving optical lattices and
load manipulation by cranes opens a route for a useful transfer of techniques

Solid-state emitters are excellent candidates for developing integrated
sources of single photons. Yet, phonons degrade the photon indistinguishability
both through pure dephasing of the zero-phonon line and through phonon-assisted
emission. Here, we study theoretically and experimentally the
indistinguishability of photons emitted by a semiconductor quantum dot in a
microcavity as a function of temperature. We show that a large coupling to a
high quality factor cavity can simultaneously reduce the effect of both

Efficient communication between qubits relies on robust networks which allow
for fast and coherent transfer of quantum information. It seems natural to
harvest the remarkable properties of systems characterized by topological
invariants to perform this task. Here we show that a linear network of coupled
bosonic degrees of freedom, characterized by topological bands, can be employed
for the efficient exchange of quantum information over large distances.
Important features of our setup are that it is robust against quenched

The observed classicality of primordial perturbations, despite their quantum
origin during inflation, calls for a mechanism for quantum-to-classical
transition of these initial fluctuations. As literature suggests a number of
plausible mechanisms which try to address this issue, it is of importance to
seek for concrete observational signatures of these several approaches in order
to have a better understanding of the early universe dynamics. Among these
several approaches, it is the spontaneous collapse dynamics of Quantum