Momentum diffusion is a possible mechanism for driving macroscopic quantum

systems towards classical behaviour. Experimental tests of this hypothesis rely

on a precise estimation of the strength of this diffusion. We show that

quantum-mechanical squeezing offers significant improvements, including when

measuring position. For instance, with 10dB of mechanical squeezing,

experiments would require a tenth of proposed free-fall times. Momentum

measurement is better by an additional factor of three, while another

# All

When absorbing boundary conditions are used to evaporate a black hole in

AdS/CFT, we show that there is a phase transition in the location of the

quantum Ryu-Takayanagi surface, at precisely the Page time. The new RT surface

lies slightly inside the event horizon, at an infalling time approximately the

scrambling time $\beta/2\pi \log S_{BH}$ into the past. We can immediately

derive the Page curve, using the Ryu-Takayanagi formula, and the

Hayden-Preskill decoding criterion, using entanglement wedge reconstruction.

In this article, we investigate the bound state solution of the Klein Gordon

equation under mixed vector and scalar coupling of an energy-dependent deformed

Hulth\'en potential in D-dimensions. We obtain a transcendental equation after

we impose the boundary conditions. We calculate energy spectra in four

different limits and in arbitrary dimension via the Newton-Raphson method.

Then, we use a statistical method, namely canonical partition function, and

We consider lattice Hamiltonian realizations of ($d$+1)-dimensional

Dijkgraaf-Witten theory. In (2+1)d, it is well-known that the Hamiltonian

yields point-like excitations classified by irreducible representations of the

twisted quantum double. This can be confirmed using a tube algebra approach. In

this paper, we propose a generalization of this strategy that is valid in any

dimensions. We then apply the tube algebra approach to derive the algebraic

structure of loop-like excitations in (3+1)d, namely the twisted quantum

The studies of multi-magnon excitations will extend our understandings of

quantum magnetism and strongly correlated matters. Here, by using the

time-evolving block decimation algorithm, we investigate the Bloch oscillations

of two-magnon excitations under a gradient magnetic field. Through analyzing

the symmetry of the Hamiltonian, we derive a rigorous and universal relation

between ferromagnetic and anti-ferromagnetic systems. Under strong

interactions, in addition to free-magnon Bloch oscillations, there appear

Isolated systems consisting of many interacting particles are generally

assumed to relax to a stationary equilibrium state whose macroscopic properties

are described by the laws of thermodynamics and statistical physics. Time

crystals, as first proposed by Wilczek, could defy some of these fundamental

laws and for instance display persistent non-decaying oscillations. They can be

engineered by external driving or contact with an environment, but are believed

Photonic switching is a key building block of many optical applications

challenging its development. We report a 2$\times$2 photonic coupler with

arbitrary splitting ratio switchable by a low-voltage electronic signal with 10

GHz bandwidth and tens of nanoseconds latency. The coupler is based on a single

Mach-Zehnder interferometer in dual-wavelength configuration allowing real-time

phase lock with sub-degree stability. The coupler can be set to any splitting

We report on the realization and verification of quantum entanglement between

an NV electron spin qubit and a telecom-band photonic qubit. First we generate

entanglement between the spin qubit and a 637 nm photonic time-bin qubit,

followed by photonic quantum frequency conversion that transfers the

entanglement to a 1588 nm photon. We characterize the resulting state by

correlation measurements in different bases and find a lower bound to the Bell

state fidelity of F = 0.77 +/- 0.03. This result presents an important step

We report on the realization of large-scale 3D multilayer configurations of

planar arrays of individual neutral atoms with immediate applications in

quantum science and technology: a microlens-generated Talbot optical lattice In

this novel platform, the single-beam illumination of a microlens array

constitutes a structurally robust and wavelength-universal method for the

realization of 3D atom arrays with favourable scaling properties due to the

inherent self-imaging of the focal structure. Thus, 3D scaling comes without

Author(s): Mohamed Abdelhafez, David I. Schuster, and Jens Koch

We present a gradient-based optimal-control technique for open quantum systems that utilizes quantum trajectories to simulate the quantum dynamics during optimization. Using trajectories allows for optimizing open systems with less computational cost than the regular density matrix approaches in mos...

[Phys. Rev. A 99, 052327] Published Mon May 20, 2019