All

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

One of the fundamental laws of classical statistical physics is the energy equipartition theorem
which states that for each degree of freedom the mean kinetic energy E k equals ##IMG##
[http://ej.iop.org/images/1751-8121/52/15/15LT01/aab03f2ieqn001.gif] , where ##IMG##
[http://ej.iop.org/images/1751-8121/52/15/15LT01/aab03f2ieqn002.gif] is the Boltzmann constant and T

We establish that the Wu–Yang monopole needs the introduction of a magnetic point source at the
origin in order for it to be a solution of the differential and integral equations for the
Yang–Mills theory. That result is corroborated by the analysis through distribution theory, of the
two types of magnetic fields relevant for the local and global properties of the Wu–Yang solution.
The subtlety lies in the fact that with the non-vanishing magnetic point source required by the

The Picard–Fuchs equation is a powerful mathematical tool which has numerous applications in
physics, for it allows one to evaluate integrals without resorting to direct integration techniques.
We use this equation to calculate both the classical action and the higher-order WKB corrections to
it, for the sextic double-well potential and the Lamé potential. Our development rests on the fact
that the Picard–Fuchs method links an integral to solutions of a differential equation with the

Author(s): Yunlan Ji, Ji Bian, Xi Chen, Jun Li, Xinfang Nie, Hui Zhou, and Xinhua Peng
The creation of multipartite entangled states is a key task of quantum information processing. Among the various implementations, shortcut to adiabaticity (STA) offers a fast and robust means for generating entanglement. The traditional counterdiabatic driving, as a conventional and simple method fo...
[Phys. Rev. A 99, 032323] Published Fri Mar 15, 2019

Author(s): D. Ahn, Y. S. Teo, H. Jeong, F. Bouchard, F. Hufnagel, E. Karimi, D. Koutný, J. Řeháček, Z. Hradil, G. Leuchs, and L. L. Sánchez-Soto
Quantum state tomography is both a crucial component in the field of quantum information and computation and a formidable task that requires an incogitable number of measurement configurations as the system dimension grows. We propose and experimentally carry out an intuitive adaptive compressive to...
[Phys. Rev. Lett. 122, 100404] Published Fri Mar 15, 2019

Author(s): Xiao-Ye Xu, Wei-Wei Pan, Qin-Qin Wang, Jan Dziewior, Lukas Knips, Yaron Kedem, Kai Sun, Jin-Shi Xu, Yong-Jian Han, Chuan-Feng Li, Guang-Can Guo, and Lev Vaidman
We report the first implementation of the von Neumann instantaneous measurements of nonlocal variables, which becomes possible due to technological achievements in creating hyperentangled photons. Tests of reliability and of the nondemolition property of the measurements have been performed with hig...
[Phys. Rev. Lett. 122, 100405] Published Fri Mar 15, 2019

Author(s): Siddharth Muthukrishnan, Tameem Albash, and Daniel A. Lidar
The glued-trees problem is the only example known to date for which quantum annealing provides an exponential speedup, albeit by partly using excited-state evolution, in an oracular setting. How robust is this speedup to noise on the oracle? To answer this, we construct phenomenological short-range ...
[Phys. Rev. A 99, 032324] Published Fri Mar 15, 2019

We present a tomographic method which requires only $4d-3$ measurement
outcomes to reconstruct \emph{any} pure quantum state of arbitrary dimension
$d$. Using the proposed scheme we have experimentally reconstructed a large
number of pure states of dimension $d=7$, obtaining a mean fidelity of $0.94$.
Moreover, we performed numerical simulations of the reconstruction process,
verifying the feasibility of the method for higher dimensions. In addition, the

Here we prove the existence and uniqueness of solutions of a class of
integral equations describing two Dirac particles in 1+3 dimensions with direct
interactions. This class of integral equations arises naturally as a
relativistic generalization of the integral version of the two-particle
Schr\"odinger equation. Crucial use of a multi-time wave function
$\psi(x_1,x_2)$ with $x_1,x_2 \in \mathbb{R}^4$ is made. A central feature is
the time delay of the interaction. Our main result is an existence and