# All

## Quantum simulation of the Sachdev-Ye-Kitaev model by asymmetric qubitization

Author(s): Ryan Babbush, Dominic W. Berry, and Hartmut Neven
We show that one can quantum simulate the dynamics of a Sachdev-Ye-Kitaev model with $N$ Majorana modes for time $t$ to precision $ε$ with gate complexity $O({N}^{7/2}t+{N}^{5/2}t\phantom{\rule{0.16em}{0ex}}\mathrm{polylog}(N/ε))$. In addition to scaling sublinearly in the number of Hamiltonian term...
[Phys. Rev. A 99, 040301(R)] Published Thu Apr 04, 2019

## On correlation functions in ##IMG## [http://ej.iop.org/images/1751-8121/52/18/184003/toc_aab0ef3ieqn001.gif] {$J\bar{T}$} -deformed CFTs

The ##IMG## [http://ej.iop.org/images/1751-8121/52/18/184003/aab0ef3ieqn003.gif] deformation, built
from the components of the stress tensor and of a ##IMG##
[http://ej.iop.org/images/1751-8121/52/18/184003/aab0ef3ieqn004.gif] current, is a universal
irrelevant deformation of two-dimensional CFTs that preserves the left-moving conformal symmetry,

## Pressure statistics from the path integral for Darcy flow through random porous media

The path integral for classical statistical dynamics is used to determine the properties of
one-dimensional Darcy flow through a porous medium with a correlated stochastic permeability for
several spatial correlation lengths. Pressure statistics are obtained from the numerical evaluation
of the path integral by using the Markov chain Monte Carlo method. Comparisons between these
pressure distributions and those calculated from the classic finite-volume method for the

## Geometry and symmetry in the quantum Boltzmann machine

Author(s): Hai-Jing Song, Tieling Song, Qi-Kai He, Yang Liu, and D. L. Zhou
The quantum Boltzmann machine extends the classical Boltzmann machine learning to the quantum regime, which makes its power to simulate the quantum states beyond the classical probability distributions. We apply the Broyden-Fletcher-Goldfarb-Shanno algorithm to study the corresponding optimization p...
[Phys. Rev. A 99, 042307] Published Wed Apr 03, 2019

## Dirac particle dynamics of a superconducting circuit

Author(s): Elisha Svetitsky and Nadav Katz
The core concept of quantum simulation is the mapping of an inaccessible quantum system onto a controllable one by identifying analogous dynamics. We map the Dirac equation of relativistic quantum mechanics in $3+1$ dimensions onto a multilevel superconducting Josephson circuit. Resonant drives dete...
[Phys. Rev. A 99, 042308] Published Wed Apr 03, 2019

## Continuous-variable measurement-device-independent quantum key distribution using modulated squeezed states and optical amplifiers

Author(s): Pu Wang, Xuyang Wang, and Yongmin Li
The measurement-device-independent quantum key distribution (MDI-QKD) protocol is immune to imperfect measurement devices. However, its practicality and performance when implemented in continuous-variable (CV) mode are still not satisfactory. We propose a CV-MDI-QKD protocol based on modulated squee...
[Phys. Rev. A 99, 042309] Published Wed Apr 03, 2019

## Observation of a Dipolar Quantum Gas with Metastable Supersolid Properties

Author(s): L. Tanzi, E. Lucioni, F. Famà, J. Catani, A. Fioretti, C. Gabbanini, R. N. Bisset, L. Santos, and G. Modugno
A novel regime of ultracold atoms is found in which a stable density modulation, known as stripes, is observed simultaneously with quantum droplets, resulting in an important advance in the search for a dipolar supersolid.
[Phys. Rev. Lett. 122, 130405] Published Wed Apr 03, 2019

## Experimental Investigation of Quantum Decay at Short, Intermediate, and Long Times via Integrated Photonics

Author(s): Andrea Crespi, Francesco V. Pepe, Paolo Facchi, Fabio Sciarrino, Paolo Mataloni, Hiromichi Nakazato, Saverio Pascazio, and Roberto Osellame
The decay of an unstable system is usually described by an exponential law. Quantum mechanics predicts strong deviations of the survival probability from the exponential: Indeed, the decay is initially quadratic, while at very large times it follows a power law, with superimposed oscillations. The l...
[Phys. Rev. Lett. 122, 130401] Published Wed Apr 03, 2019

## Inequivalent multipartite coherence classes and two operational coherence monotones

Author(s): Yu Luo, Yongming Li, and Min-Hsiu Hsieh
Quantum coherence has received significant attention in recent years, but the structure of multipartite coherent states is unclear. In this paper, we generalize important results in multipartite entanglement theory to their counterparts in quantum coherence theory. First, we give a necessary and suf...
[Phys. Rev. A 99, 042306] Published Wed Apr 03, 2019

## Generalized Landauer formula for time-dependent potentials and noise-induced zero-bias dc current

Using a new developed single-electron approach, we derive the Landauer-type formula for electron
transport in arbitrary time-dependent potentials. This formula is applied for randomly fluctuating
potentials represented by a dichotomic noise. We found that the noise can produce dc-current in
quantum system under zero-bias voltage by breaking the time-reversal symmetry of the transmission
coefficient. We show that this effect is due to decoherence, produced by the noise, which can take
place in many different systems.