As with any quantum computing platform, semiconductor quantum dot devices
require sophisticated hardware and controls for operation. The increasing
complexity of quantum dot devices necessitates the advancement of automated
control software and image recognition techniques for rapidly evaluating charge
stability diagrams. We use an image analysis toolbox developed in Python to
automate the calibration of virtual gates, a process that previously involved a
large amount of user intervention. Moreover, we show that straightforward

We propose a practical protocol to generate and observe a non-Abelian
geometric phase using a periodically driven Raman process in the hyperfne
ground state manifold of atoms in a dilute ultracold gas. Our analysis is based
upon recent developments and application of Floquet theory to periodically
driven quantum systems. The simulation results show the non-Abelian gauge
transformation and the non-commuting property of the SU(2) transformation
operators. Based on these results, we propose a possible experimental

We present a $2\mathrm{-dimensional}$ quantum walker on curved discrete
surfaces with dynamical geometry. This walker extends the quantum walker over
the fixed triangular lattice introduced in
\cite{quantum_walk_triangular_lattice}. We write the discrete equations of the
walker on an arbitrary triangulation, whose flat spacetime limit recovers the
Dirac equation in (2+1)-dimension. The geometry is changed through Pachner
moves, allowing the surface to transform into any topologically equivalent

Universal properties of a critical quantum spin chain are encoded in the
underlying conformal field theory (CFT). This underlying CFT is fully
characterized by its conformal data. We propose a method to extract the
conformal data from a critical quantum spin chain with both periodic and
anti-periodic boundary conditions (PBC and APBC) based on low-energy
eigenstates, generalizing previous work on spin chains with only PBC. First,
scaling dimensions and conformal spins are extracted from the energies and

We introduce quantum circuits in two and three spatial dimensions which are
classically simulable, despite producing a high degree of operator
entanglement. We provide a partial characterization of these "automaton"
quantum circuits, and use them to study operator growth, information spreading,
and local charge relaxation in quantum dynamics with subsystem symmetries,
which we define as overlapping symmetries that act on lower-dimensional
submanifolds. With these symmetries, we discover the anomalous subdiffusion of

A powerful tool for studying the behavior of classical field theories is
Derrick's theorem: one may rule out the existence of localized inhomogeneous
stable field configurations (solitons) by inspecting the Hamiltonian and making
scaling arguments. For example, the theorem can be used to rule out compact
domain wall configurations for the classic $\phi^4$ theory in $3+1$ dimensions
and greater. We argue no such obstruction to constructing solitons exists in

One of the stunning consequences of quantum correlations in thermodynamics is
the reversal of the arrow of time, recently shown experimentally in [K.
Micadei, et al., Nat. Commun. 10:2456 (2019)], and manifesting itself by a
reversal of the heat flow (from the cold system to the hot one). Here, we show
that contrary to what could have been expected, heat flow reversal can happen
without reversal of the arrow of time. Moreover, contrasting with previous

Consider a classical system, which is in the state described by probability
distribution $p$ or $q$, and embed these classical informations into quantum
system by a physical map $\Gamma$, $\rho=\Gamma(p)$ and $\sigma=\Gamma(q)$.
Intuitively, the pair $\{p_{\rho}^{M},p_{\sigma}^{M}\}$ of the distributions of
the data of the measurement $M$ on the pair $\{\rho,\sigma\}$ should contain
strictly less information than the pair $\{p,q\}$ provided the pair
$\{\rho,\sigma\}$ is non-commutative. Indeed, this statement had been shown if

Author(s): Jia-Qi Zhou, Ling Cai, Qi-Ping Su, and Chui-Ping Yang
Implementation of a discrete-time quantum walk (DTQW) with superconducting qubits is difficult since on-chip superconducting qubits cannot hop between lattice sites. We propose an efficient protocol for the implementation of DTQW in circuit quantum electrodynamics (QED), in which only $N+1$ qutrits,...
[Phys. Rev. A 100, 012343] Published Thu Jul 25, 2019

Author(s): Yafei Wen, Pai Zhou, Zhongxiao Xu, Liang Yuan, Haoyi Zhang, Shengzhi Wang, Long Tian, Shujing Li, and Hai Wang
A source that can generate atom-photon quantum correlations or entanglement based on a quantum memory is a basic building block of quantum repeaters (QRs). To achieve high entanglement generation rates in ensemble-based QRs, spatial-, temporal-, and spectral-multimode memories are needed. Previous t...
[Phys. Rev. A 100, 012342] Published Thu Jul 25, 2019