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

# All

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

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

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

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

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

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

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

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

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