# All

## Ground-State Phase Diagram of a Spin-Orbital-Angular-Momentum Coupled Bose-Einstein Condensate

Author(s): Dongfang Zhang, Tianyou Gao, Peng Zou, Lingran Kong, Ruizong Li, Xing Shen, Xiao-Long Chen, Shi-Guo Peng, Mingsheng Zhan, Han Pu, and Kaijun Jiang
By inducing a Raman transition using a pair of Gaussian and Laguerre-Gaussian laser beams, we realize a $^{87}\mathrm{Rb}$ condensate whose orbital angular momentum (OAM) and its internal spin states are coupled. By varying the detuning and the coupling strength of the Raman transition, we experimen...
[Phys. Rev. Lett. 122, 110402] Published Wed Mar 20, 2019

## Randomized benchmarking under different gate sets

Author(s): Kristine Boone, Arnaud Carignan-Dugas, Joel J. Wallman, and Joseph Emerson
We provide a comprehensive analysis of the differences between two important standards for randomized benchmarking (RB): the Clifford-group RB protocol proposed originally in Emerson et al. [J. Opt. B 7, S347 (2005)] and Dankert et al. [Phys. Rev. A 80, 012304 (2009)], and a variant of that RB proto...
[Phys. Rev. A 99, 032329] Published Wed Mar 20, 2019

## Matter-Wave Diffraction from a Quasicrystalline Optical Lattice

Author(s): Konrad Viebahn, Matteo Sbroscia, Edward Carter, Jr-Chiun Yu, and Ulrich Schneider
Experimentalists realize a Bose-Einstein condensate on a 2D quasicrystal optical lattice, opening new perspectives for the simulation of quantum many-body phenomena in a fractal structure.
[Phys. Rev. Lett. 122, 110404] Published Wed Mar 20, 2019

## Experimental Demonstration of Quantum Effects in the Operation of Microscopic Heat Engines

Author(s): James Klatzow, Jonas N. Becker, Patrick M. Ledingham, Christian Weinzetl, Krzysztof T. Kaczmarek, Dylan J. Saunders, Joshua Nunn, Ian A. Walmsley, Raam Uzdin, and Eilon Poem
Experiments demonstrate a quantum-coherence-induced power increase for quantum heat engines over their classical counterparts.
[Phys. Rev. Lett. 122, 110601] Published Wed Mar 20, 2019

## Classifying quantum data by dissipation

Author(s): Jeffrey Marshall, Lorenzo Campos Venuti, and Paolo Zanardi
We investigate a general class of dissipative quantum circuit capable of computing arbitrary conjunctive normal form (CNF) Boolean formulas. In particular, the clauses in a CNF formula define a local generator of Markovian quantum dynamics which acts on a network of qubits. Fixed points of this dyna...
[Phys. Rev. A 99, 032330] Published Wed Mar 20, 2019

## Genuine 12-Qubit Entanglement on a Superconducting Quantum Processor

Author(s): Ming Gong, Ming-Cheng Chen, Yarui Zheng, Shiyu Wang, Chen Zha, Hui Deng, Zhiguang Yan, Hao Rong, Yulin Wu, Shaowei Li, Fusheng Chen, Youwei Zhao, Futian Liang, Jin Lin, Yu Xu, Cheng Guo, Lihua Sun, Anthony D. Castellano, Haohua Wang, Chengzhi Peng, Chao-Yang Lu, Xiaobo Zhu, and Jian-Wei Pan
Twelve superconducting qubits are entangled, forming a linear cluster state, by using a carefully calibrated sequence of single and 2-qubit quantum gates.
[Phys. Rev. Lett. 122, 110501] Published Wed Mar 20, 2019

## The focusing problem for the Leith model of turbulence: a self-similar solution of the third kind

Time-dependend evolution of hydrodynamic turbulence corresponding to formation of a thermodynamic
state at the large-scale part of the spectrum is studied using the inviscid Leith model. In the wave
vector space, the evolution leads to shrinking of the zero-spectrum ‘hole’—the so-called focusing
problem. However, in contrast with the typical focusing problem in the nonlinear filtration theory,
the focusing time is infinite for the Leith model. Respectively, the evolution is described by a

## PT-symmetric quantum graphs

We consider PT-symmetric quantum graphs, in which the branching points provide PT-symmetric boundary
conditions for the Schrödinger equation on a graph. For such branched quantum wires, we derive
general boundary conditions, which keep the Hamiltonian as PT-symmetric with real eigenvalues and
positively defined norm of the eigenfunctions. Secular equations for finding the eigenvalues of the
quantum graph are derived. Breaking the Kirchhoff rule at the branching points in such systems is

## Super-Lagrangian and variational principle for generalized continuity equations

We present a variational approach which shows that the wave functions belonging to quantum systems
in different potential landscapes, are pairwise linked to each other through a generalized
continuity equation. This equation contains a source term proportional to the potential difference.
In case the potential landscapes are related by a linear symmetry transformation in a finite domain
of the embedding space, the derived continuity equation leads to generalized currents which are

## Quantum leakage detection using a model-independent dimension witness

Author(s): Armands Strikis, Animesh Datta, and George C. Knee
Users of quantum computers must be able to confirm they are functioning as intended, even when they are remotely accessed. In particular, if the Hilbert space dimension of the quantum computer components is not as advertised—for instance, if they suffer leakage—errors can ensue and protocols may be ...
[Phys. Rev. A 99, 032328] Published Tue Mar 19, 2019