# All

## Quantum correlations for anonymous metrology. (arXiv:1812.04374v3 [quant-ph] UPDATED)

We introduce the task of anonymous metrology, in which a physical parameter
of an object may be determined without revealing the object's location. Alice
and Bob share a correlated quantum state, with which one of them probes the
object. Upon receipt of the quantum state, Charlie is then able to estimate the
parameter without knowing who possesses the object. We show that quantum
correlations are resources for this task when Alice and Bob do not trust the

## Random Quantum Batteries. (arXiv:1908.08064v1 [quant-ph])

Quantum nano-devices are fundamental systems in quantum thermodynamics that
have been the subject of profound interest in recent years. Among these,
quantum batteries play a very important role. In this paper we lay down a
theory of random quantum batteries and provide a systematic way of computing
the average work and work fluctuations in such devices by investigating their
typical behavior. We show that the performance of random quantum batteries
exhibits typicality and depends only on the spectral properties of the time

## Quantum key distribution with correlated sources. (arXiv:1908.08261v1 [quant-ph])

Implementation security is a critical problem in quantum key distribution
(QKD). With the advent of measurement-device-independent QKD, all security
loopholes of the measurement unit have been closed. Securing the source,
however, remains an elusive issue. Despite the tremendous progress made by
developing security proofs that accommodate most typical source imperfections,
such proofs usually disregard the effect of pulse correlations. That is, they
disregard the fact that the state of an emitted signal can depend on the

## Hyperfine level structure in nitrogen-vacancy centers near the ground-state level anticrossing. (arXiv:1805.01251v3 [quant-ph] UPDATED)

Energy levels of nitrogen-vacancy centers in diamond were investigated using
optically detected magnetic-resonance spectroscopy near the electronic
ground-state level anticrossing (GSLAC) at an axial magnetic field around
102.4~mT in diamond samples with a nitrogen concentration of 1~ppm and 200~ppm.
By applying radiowaves in the frequency ranges from 0 to 40 MHz and from 5.6 to
5.9 GHz, we observed transitions that involve energy levels mixed by the
hyperfine interaction. We developed a theoretical model that describes the

## Measurement reduction in variational quantum algorithms. (arXiv:1908.08067v1 [quant-ph])

Variational quantum algorithms are promising applications of noisy
intermediate-scale quantum (NISQ) computers. These algorithms consist of a
number of separate prepare-and-measure experiments that estimate terms in the
Hamiltonian. The number of separate measurements required can become
overwhelmingly large for problems at the scale of NISQ hardware that may soon
be available. We approach this problem from the perspective of contextuality,
and use unitary partitioning (developed independently by Izmaylov \emph{et

## Conditional Teleportation of Quantum-Dot Spin States. (arXiv:1908.08306v1 [cond-mat.mes-hall])

Among the different experimental platforms for quantum information
processing, individual electron spins in semiconductor quantum dots stand out
for their long coherence times and potential for scalable fabrication. The past
years have witnessed substantial progress in the capabilities of spin qubits.
However, coupling between distant electron spins, which is required for quantum
error correction, presents a challenge, and this goal remains the focus of

## Regenesis and quantum traversable wormholes. (arXiv:1810.01444v2 [hep-th] UPDATED)

Recent gravity discussions of a traversable wormhole indicate that in
holographic systems signals generated by a source could reappear long after
they have dissipated, with the need of only performing some simple operations.
In this paper we argue the phenomenon, to which we refer as "regenesis", is
universal in general quantum chaotic many-body systems, and elucidate its
underlying physics. The essential elements behind the phenomenon are: (i)
scrambling which in a chaotic system makes out-of-time-ordered correlation

## The Classical Complexity of Gaussian Boson Sampling. (arXiv:1908.08068v1 [quant-ph])

We introduce an exact classical algorithm for simulating Gaussian Boson
Sampling (GBS). The complexity of the algorithm is exponential in the number of
photons detected, which is itself a random variable. For a fixed number of
modes, the complexity is in fact equivalent to that of calculating output
probabilities, up to constant prefactors. The simulation algorithm can be
extended to other models such as GBS with threshold detectors, GBS with
displacements, and sampling linear combinations of Gaussian states. In the

## Pretty simple bounds on quantum state discrimination. (arXiv:1908.08312v1 [quant-ph])

We show that the quantum measurement known as the pretty good measurement can
be used to identify an unknown quantum state picked from any set of $n$ mixed
states that have pairwise fidelities upper-bounded by a constant below 1, given
$O(\log n)$ copies of the unknown state, with high success probability in the
worst case. If the unknown state is promised to be pure, there is an explicit
measurement strategy which solves this worst-case quantum state discrimination

## Fundamental limits on key rates in device-independent quantum key distribution. (arXiv:1810.05627v2 [quant-ph] UPDATED)

In this paper, we introduce intrinsic non-locality as a quantifier for Bell
non-locality, and we prove that it satisfies certain desirable properties such
as faithfulness, convexity, and monotonicity under local operations and shared
randomness. We then prove that intrinsic non-locality is an upper bound on the
secret-key-agreement capacity of any device-independent protocol conducted
using a device characterized by a correlation $p$. We also prove that intrinsic