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At zero energy the Dirac equation has interesting behaviour. The asymmetry in

the number of spin up and spin down modes is determined by the topology of both

space and the gauge field in which the system sits. An analogous phenomenon

also occurs in electromagnetism. Writing Maxwell's equations in a Dirac-like

form, we identify cases where a material parameter plays the role of energy. At

zero energy we thus find electromagnetic modes that are indifferent to local

We consider a protocol for sharing quantum states using continuous variable

systems. Specifically we introduce an encoding procedure where bosonic modes in

arbitrary secret states are mixed with several ancillary squeezed modes through

a passive interferometer. We derive simple conditions on the interferometer for

this encoding to define a secret sharing protocol and we prove that they are

satisfied by almost any interferometer. This implies that, if the

Quantum tomography is currently ubiquitous for testing any implementation of

a quantum information processing device. Various sophisticated procedures for

state and process reconstruction from measured data are well developed and

benefit from precise knowledge of the model describing state preparation and

the measurement apparatus. However, physical models suffer from intrinsic

limitations as actual measurement operators and trial states cannot be known

The electron and positron magnetic moments are the most precise prediction of

the standard model of particle physics. The most accurate measurement of a

property of an elementary particle has been made to test this result. A new

experimental method is now being employed in an attempt to improve the

measurement accuracy by an order of magnitude. Positrons from a "student

source" now suffice for the experiment. Progress toward a new measurement is

summarized.

Solid-state experimental realizations of Majorana bound states are based on

materials with strong intrinsic spin-orbit interactions. In this work, we

explore an alternative approach where spin-orbit coupling is induced

artificially through a non-uniform magnetic field that originates from an array

of micromagnets. Using a recently developed optimization algorithm, we find

suitable micromagnet geometries for the emergence of topological

superconductivity in a one-dimensional wire without intrinsic spin-orbit

High-fidelity entangling quantum gates based on Rydberg interactions are

required for scalable quantum computing with neutral atoms. Their realization,

however, meets a major stumbling block -- the motion-induced dephasing of the

transition between the ground and Rydberg states. By using quantum interference

between different detuned Rabi oscillations, we propose a practical scheme to

realize a class of accurate entangling Rydberg quantum gates subject to a

The so-called information-thermodynamics link created by a thought experiment of Szilard became a

core of modern orthodoxy in the field of quantum information and resources theory in quantum

thermodynamics. We recall existing objections against standard interpretation of Szilard engine

operation and illustrate them by two quantum models: a particle in a box with time-dependent thin

potential barrier and the spin-boson model. The consequences of the emerging superselection rules

- Read more about Information-thermodynamics link revisited
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In this paper we present a rigorous method for deciding whether a birational three point mapping

that has the singularity confinement property is integrable or not, based only on the structure of

its (confined) singularity patterns. We also explain how the exact value of the dynamical degree for

such a mapping may be deduced from the singularity patterns.

- Read more about Singularity confinement as an integrability criterion
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The B 1 vertex model is studied by the off-diagonal Bethe ansatz method. New closed operator product

identities of the fused transfer matrices are obtained by using the fusion technique. Based on them

and the asymptotic behaviors as well as the values of the fused transfer matrices at certain points,

the exact solutions of the B 1 model with periodic and with integrable off-diagonal open boundary

conditions are obtained. We find that the degree of the polynomial of the inhomogeneous T − Q

- Read more about Exact solution of the B 1 model
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Author(s): Xudan Chai, Yi-Ping Lu, An-ning Zhang, and Qing Zhao

Quantum state tomography is of crucial importance in assessing the quality of quantum information processing devices. Tomography fundamentally requires both experiments and data processing resources, which increase exponentially with the size of qubits. We propose using phase lift to precisely chara...

[Phys. Rev. A 99, 042321] Published Fri Apr 12, 2019