# All

## 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

## 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

## 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

## 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

## 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

## Inhibition of spreading in quantum random walks due to quenched Poisson-distributed disorder

We consider a quantum particle (walker) on a line that coherently chooses to jump to the left or right depending on the result of a toss of a quantum coin. The lengths of the jumps are considered to be independent and identically distributed quenched Poisson random variables. We find that the spread...
[Phys. Rev. A 99, 042329] Published Mon Apr 22, 2019

## Entanglement-assisted communication in the absence of shared reference frame

Author(s): Ali Beheshti, Sadegh Raeisi, and Vahid Karimipour
Alice wants to convey the value of a parameter to Bob with whom she does not share a reference frame. What physical object can she use for this task? Shall she encode this value into the angle between two physical vectors such as the angle between two spins? Can she benefit from using entanglement? ...
[Phys. Rev. A 99, 042330] Published Mon Apr 22, 2019

## Generic Bound Coherence under Strictly Incoherent Operations

Author(s): Ludovico Lami, Bartosz Regula, and Gerardo Adesso
We compute analytically the maximal rates of distillation of quantum coherence under strictly incoherent operations (SIO) and physically incoherent operations (PIO), showing that they coincide for all states, and providing a complete description of the phenomenon of bound coherence. In particular, w...
[Phys. Rev. Lett. 122, 150402] Published Fri Apr 19, 2019

## Ballistic Spin Transport in a Periodically Driven Integrable Quantum System

Author(s): Marko Ljubotina, Lenart Zadnik, and Tomaž Prosen
We demonstrate ballistic spin transport of an integrable unitary quantum circuit, which can be understood either as a paradigm of an integrable periodically driven (Floquet) spin chain, or as a Trotterized anisotropic ($XXZ$) Heisenberg spin-$1/2$ model. We construct an analytic family of quasilocal...
[Phys. Rev. Lett. 122, 150605] Published Fri Apr 19, 2019