We introduce a multi-step protocol for optical quantum state engineering that

performs as deterministic "bright quantum scissors" (BQS), namely truncates an

arbitrary input quantum state to have at least a certain number of photons. The

protocol exploits single-photon pulses and is based on the effect of

single-photon Raman interaction, which is implemented with a single three-level

$\Lambda$ system (e.g. a single atom) Purcell-enhanced by a single-sided

cavity. A single step of the protocol realises the inverse of the bosonic

# All

The equivalence principle in combination with the special relativistic

equivalence between mass and energy, $E=mc^2$, is one of the cornerstones of

general relativity. However, for composite systems a long-standing result in

general relativity asserts that the passive gravitational mass is not simply

equal to the total energy. This seeming anomaly is supported by all explicit

derivations of the dynamics of bound systems, and is only avoided after

time-averaging. Here we rectify this misconception and derive from first

This paper is devoted to the study of the evolution of holographic complexity

after a local perturbation of the system at finite temperature. We calculate

the complexity using both the complexity=action(CA) and the

complexity=volume(CA) conjectures and find that the CV complexity of the total

state shows the unbounded late time linear growth. The CA computation shows

linear growth with fast saturation to a constant value. We estimate the CV and

CA complexity linear growth coefficients and show, that finite temperature

We may infer a transition $|n \rangle \to |m \rangle$ between energy

eigenstates of an open quantum system by observing the emission of a photon of

Bohr frequency $\omega_{mn} = (E_n-E_m) / \hbar$. In addition to the

"collapses" to the state $|m\rangle$, the measurement must also have brought

into existence the pre-measurement state $|n \rangle$. As quantum trajectories

are based on past observations, the condition state will jump to $| m \rangle$,

but the state $|n\rangle$ does not feature in any essential way. We resolve

We introduce an approach to find the Tomita-Takesaki modular flow for

multi-component regions in chiral conformal field theory. Our method is based

only locality (or braid-relations) of primary fields and the so-called

Kubo-Martin-Schwinger (KMS) condition. These methods can be used to transform

the problem to a Riemann-Hilbert problem on a covering of the complex plane cut

along the regions. The method for instance gives a formula for the modular flow

in the case of a thermal state for the free fermion net, but is in principle

Recent technological breakthroughs have precipitated the availability of

specialized devices that promise to solve NP-Hard problems faster than standard

computers. These `Ising Machines' are however analog in nature and as such

inevitably have implementation errors. We find that their success probability

decays exponentially with problem size for a fixed error level, and we derive a

sufficient scaling law for the error in order to maintain a fixed success

probability. We corroborate our results with experiment and numerical

We propose a novel type of composite light-matter interferometer based on a

supersolid-like phase of a driven Bose-Einstein condensate coupled to a pair of

degenerate counterpropagating electromagnetic modes of an optical ring cavity.

The supersolid-like condensate under the influence of the gravity drags the

cavity optical potential with itself, thereby changing the relative phase of

the two {cavity electromagnetic fields}. Monitoring the phase evolution of the

Geometric integrators of the Schr\"{o}dinger equation conserve exactly many

invariants of the exact solution. Among these integrators, the split-operator

algorithm is explicit and easy to implement, but, unfortunately, is restricted

to systems whose Hamiltonian is separable into a kinetic and potential terms.

Here, we describe several implicit geometric integrators applicable to both

separable and non-separable Hamiltonians, and, in particular, to the

nonadiabatic molecular Hamiltonian in the adiabatic representation. These

In compressed sensing one uses known structures of otherwise unknown signals

to recover them from as few linear observations as possible. The structure

comes in form of some compressibility including different notions of sparsity

and low rankness. In many cases convex relaxations allow to efficiently solve

the inverse problems using standard convex solvers at almost-optimal sampling

rates. A standard practice to account for multiple simultaneous structures in

Nuclear spins in the solid state have long been envisaged as a platform for

quantum computing, due to their long coherence times and excellent

controllability. Measurements can be performed via localised electrons, for

example those in single atom dopants or crystal defects. However, establishing

long-range interactions between multiple dopants or defects is challenging.

Conversely, in lithographically-defined quantum dots, tuneable interdot

electron tunnelling allows direct coupling of electron spin-based qubits in