# All

## Foundations of quantum physics I. A critique of the tradition. (arXiv:1902.10778v2 [quant-ph] UPDATED)

This paper gives a thorough critique of the foundations of quantum physics in
its mainstream interpretation (i.e., treating pure states as primitives,
without reference to hidden variables, and without modifications of the quantum
laws). This is achieved by cleanly separating a concise version of the
(universally accepted) formal core of quantum physics from the (controversial)
interpretation issues. The latter are primarily related to measurement, but
also to questions of existence and of the meaning of basic concepts like

## Material Size Dependence on Fundamental Constants

Author(s): Lukáš F. Pašteka, Yongliang Hao, Anastasia Borschevsky, Victor V. Flambaum, and Peter Schwerdtfeger
Searching for variations in fundamental constants—which are predicted by some theories of dark matter—might potentially be done by monitoring the sizes of solid crystals.
[Phys. Rev. Lett. 122, 160801] Published Wed Apr 24, 2019

## Cluster State Generation with Spin-Orbit Coupled Fermionic Atoms in Optical Lattices

Author(s): M. Mamaev, R. Blatt, J. Ye, and A. M. Rey
Measurement-based quantum computation, an alternative paradigm for quantum information processing, uses simple measurements on qubits prepared in cluster states, a class of multiparty entangled states with useful properties. Here we propose and analyze a scheme that takes advantage of the interplay ...
[Phys. Rev. Lett. 122, 160402] Published Wed Apr 24, 2019

## Kinked Entropy and Discontinuous Microcanonical Spontaneous Symmetry Breaking

Author(s): Hai-Jun Zhou
Spontaneous symmetry breaking (SSB) in statistical physics is a macroscopic collective phenomenon. For the paradigmatic $Q$-state Potts model it means a transition from the disordered color-symmetric phase to an ordered phase in which one color dominates. Existing mean field theories imply that SSB ...
[Phys. Rev. Lett. 122, 160601] Published Wed Apr 24, 2019

## Simulation Complexity of Open Quantum Dynamics: Connection with Tensor Networks

Author(s): I. A. Luchnikov, S. V. Vintskevich, H. Ouerdane, and S. N. Filippov
The difficulty to simulate the dynamics of open quantum systems resides in their coupling to many-body reservoirs with exponentially large Hilbert space. Applying a tensor network approach in the time domain, we demonstrate that effective small reservoirs can be defined and used for modeling open qu...
[Phys. Rev. Lett. 122, 160401] Published Tue Apr 23, 2019

## Approximate exchange-only entangling gates for the three-spin-$1/2$ decoherence-free subsystem

Author(s): James R. van Meter and Emanuel Knill
The three-spin-$1/2$ decoherence-free subsystem defines a logical qubit protected from collective noise and supports exchange-only universal gates. Such logical qubits are well suited for implementation with electrically defined quantum dots. Exact exchange-only entangling logical gates exist but ar...
[Phys. Rev. A 99, 042331] Published Tue Apr 23, 2019

## Two-dimensional Wigner crystals of classical Lennard-Jones particles

The ground-state of two-dimensional (2D) systems of classical particles interacting pairwisely by
the generalized Lennard-Jones potential is studied. Taking the surface area per particle A as a free
parameter and restricting oneself to periodic Bravais lattices with one particle per unit cell,
Bétermin (2018 Nonlinearity 31 3973) proved that the hexagonal, rhombic, square and rectangular
structures minimize successively the interaction energy per particle as A increases. We show here

## Generalisation of Chaplygin’s reducing multiplier theorem with an application to multi-dimensional nonholonomic dynamics

A generalisation of Chaplygin’s reducing multiplier theorem is given by providing sufficient
conditions for the Hamiltonisation of Chaplygin nonholonomic systems with an arbitrary number r of
degrees of freedom via Chaplygin’s multiplier method. The crucial point in the construction is to
add an hypothesis of geometric nature that controls the interplay between the kinetic energy metric
and the non-integrability of the constraint distribution. Such hypothesis can be systematically

## Kinetic regimes in aggregating systems with spontaneous and collisional fragmentation

We analyze systems of clusters and interacting upon colliding—a collision between two clusters may
lead to merging or fragmentation—and we also investigate the influence of additional spontaneous
fragmentation events. We consider both closed systems in which the total mass remains constant and
open systems driven by a source of small-mass clusters. In closed systems, the size distribution of
aggregates approaches a steady state. For these systems the relaxation time and the steady state

## Experimental simulation of shift operators in a quantum processor

Author(s): Xiangyu Kong, Shijie Wei, Jingwei Wen, Tao Xin, and Gui-Lu Long
The ability to implement quantum operations plays a fundamental role in manipulating quantum systems. Creation and annihilation operators which transform one quantum state into another by adding or subtracting a particle are crucial in constructing the quantum description of many-body quantum theory...
[Phys. Rev. A 99, 042328] Published Mon Apr 22, 2019