Reply to 'Comment on "Detuning effects in the one-photon mazer" '

We refute in this Reply the criticisms made by M. Abdel-Aty [Phys. Rev. A 70, 047801 (2004)]. We show that none of them are founded and we demonstrate very explicitly what is wrong in the arguments developed by this author.Comment: 5 pages, 2 figure

Phase space tweezers for tailoring cavity fields by quantum Zeno dynamics

We discuss an implementation of Quantum Zeno Dynamics in a Cavity Quantum Electrodynamics experiment. By performing repeated unitary operations on atoms coupled to the field, we restrict the field evolution in chosen subspaces of the total Hilbert space. This procedure leads to promising methods for tailoring non-classical states. We propose to realize `tweezers' picking a coherent field at a point in phase space and moving it towards an arbitrary final position without affecting other non-overlapping coherent components. These effects could be observed with a state-of-the-art apparatus

Generating and Revealing a Quantum Superposition of Electromagnetic Field Binomial States in a Cavity

We introduce the $N$-photon quantum superposition of two orthogonal generalized binomial states of electromagnetic field. We then propose, using resonant atom-cavity interactions, non-conditional schemes to generate and reveal such a quantum superposition for the two-photon case in a single-mode high-$Q$ cavity. We finally discuss the implementation of the proposed schemes.Comment: 4 pages, 3 figures. Title changed (published version

Mesoscopic ensembles of polar bosons in triple-well potentials

Mesoscopic dipolar Bose gases in triple-well potentials offer a minimal system for the analysis of the long-range character of the dipole-dipole interactions. We show that this long-range character may be clearly revealed by a variety of possible ground-state phases. In addition, an appropriate control of short-range and dipolar interactions may lead to novel scenarios for the dynamics of atoms and polar molecules in lattices, including the dynamical creation of mesoscopic Schr\"odinger cats, which may be employed as a source of highly-nonclassical states for Heisenberg-limited interferometry.Comment: 4 pages, 3 figures. Identical to the published version, including supplemental material (4 pages, 6 figures)

Continuous monitoring can improve indistinguishability of a single-photon source

A new engineering technique using continuous quantum measurement in conjunction with feed-forward is proposed to improve indistinguishability of a single-photon source. The technique involves continuous monitoring of the state of the emitter, processing the noisy output signal with a simple linear estimation algorithm, and feed forward to control a variable delay at the output. In the weak coupling regime, the information gained by monitoring the state of the emitter is used to reduce the time uncertainty inherent in photon emission from the source, which improves the indistinguishability of the emitted photons.Comment: 4 pages, 4 figure

Qubit-oscillator system under ultrastrong coupling and extreme driving

We introduce an approach to studying a driven qubit-oscillator system in the ultrastrong coupling regime, where the ratio $g/\Omega$ between coupling strength and oscillator frequency approaches unity or goes beyond, and simultaneously for driving strengths much bigger than the qubit energy splitting (extreme driving). Both qubit-oscillator coupling and external driving lead to a dressing of the qubit tunneling matrix element of different nature: the former can be used to suppress selectively certain oscillator modes in the spectrum, while the latter can bring the qubit's dynamics to a standstill at short times (coherent destruction of tunneling) even in the case of ultrastrong coupling.Comment: 4+ pages, 5 figures (published version

A ‘Geopolitical Commission’: Supranationalism Meets Global Power Competition

This article examines the origins and operationalisation of the concept of a ‘geopolitical Commission’, which has been promoted by President of the European Commission Ursula von der Leyen since 2019. This concept has been used to guide the stronger co-ordination of the external aspects of the Commission’s work. It is also symptomatic of the growing role of strategic considerations in the Commission’s recent initiatives, particularly through the objective of strengthening the EU’s ‘open strategic autonomy’. To explain this phenomenon, I combine three different theoretical perspectives: neorealism, neofunctionalism, and geoeconomics. I conclude that the geopolitical Commission should be understood as the result of the interactions between exogenous factors–the intensification of global power competition and the rise of geoeconomic strategies–and endogenous factors, such as the rivalry between the Commission and the European ExternalAction Service and the functional link between the Commission’s economic powers and international security issues

Fermionic collective excitations in a lattice gas of Rydberg atoms

We investigate the many-body quantum states of a laser-driven gas of Rydberg atoms confined to a large spacing ring lattice. If the laser driving is much stronger than the van-der-Waals interaction among the Rydberg sates, these many-body states are collective fermionic excitations. The first excited state is a spin-wave that extends over the entire lattice. We demonstrate that our system permits to study fermions in the presence of disorder although no external atomic motion takes place. We analyze how this disorder influences the excitation properties of the fermionic states. Our work shows a route towards the creation of complex many-particle states with atoms in lattices

Why the EU needs a wartime investment plan

EU member states moved quickly to provide support to Ukraine following Russia’s invasion in February. However, with an extended conflict now looking likely, the EU can no longer rely on short-term ad-hoc measures, writes Pierre Haroche. Instead, European leaders should establish a coherent Wartime INvestment (WIN) plan to both support Ukraine and provide coordinated investments in the military capabilities of EU member states

Dynamical Behavior of a Squid Ring Coupled to a Quantized Electromagnetic Field

In this paper we investigate the dynamical behavior of a SQUID ring coupled to a quantized single-mode electromagnetic field. We have calculated the eigenstates of the combined fully quantum mechanical SQUID-field system. Interesting phenomena occur when the energy difference between the usual symmetric and anti-symmetric SQUID states equals the field energy . We find the low-energy lying entangled stationary states of the system and demonstrate that its dynamics is dominated by coherent Rabi oscillations.Comment: 6 pages, 2 figures. to be published on International Journal of Modern Physics