718 research outputs found
All Optical Switch of Vacuum Rabi Oscillations: The Ultrafast Quantum Eraser
We study the all-optical time-control of the strong coupling between a single
cascade three-level quantum emitter and a microcavity. We find that only
specific arrival-times of the control pulses succeed in switching-off the Rabi
oscillations. Depending on the arrival times of control pulses, a variety of
exotic non-adiabatic cavity quantum electrodynamics effects can be observed. We
show that only control pulses with specific arrival times are able to suddenly
switch-off and -on first-order coherence of cavity photons, without affecting
their strong coupling population dynamics. Such behavior may be understood as a
manifestation of quantum complementarity
Towards formal models and languages for verifiable Multi-Robot Systems
Incorrect operations of a Multi-Robot System (MRS) may not only lead to
unsatisfactory results, but can also cause economic losses and threats to
safety. These threats may not always be apparent, since they may arise as
unforeseen consequences of the interactions between elements of the system.
This call for tools and techniques that can help in providing guarantees about
MRSs behaviour. We think that, whenever possible, these guarantees should be
backed up by formal proofs to complement traditional approaches based on
testing and simulation.
We believe that tailored linguistic support to specify MRSs is a major step
towards this goal. In particular, reducing the gap between typical features of
an MRS and the level of abstraction of the linguistic primitives would simplify
both the specification of these systems and the verification of their
properties. In this work, we review different agent-oriented languages and
their features; we then consider a selection of case studies of interest and
implement them useing the surveyed languages. We also evaluate and compare
effectiveness of the proposed solution, considering, in particular, easiness of
expressing non-trivial behaviour.Comment: Changed formattin
Photodetection probability in quantum systems with arbitrarily strong light-matter interaction
Cavity-QED systems have recently reached a regime where the light-matter
interaction strength amounts to a non-negligible fraction of the resonance
frequencies of the bare subsystems. In this regime, it is known that the usual
normal-order correlation functions for the cavity-photon operators fail to
describe both the rate and the statistics of emitted photons. Following
Glauber's original approach, we derive a simple and general quantum theory of
photodetection, valid for arbitrary light-matter interaction strengths. Our
derivation uses Fermi's golden rule, together with an expansion of system
operators in the eigenbasis of the interacting light-matter system, to arrive
at the correct photodetection probabilities. We consider both narrow- and
wide-band photodetectors. Our description is also valid for point-like
detectors placed inside the optical cavity. As an application, we propose a
gedanken experiment confirming the virtual nature of the bare excitations that
enrich the ground state of the quantum Rabi model.Comment: 9 pages, 1 figur
Theory of local optical spectroscopy of quantum wires with interface fluctuations
We present a theory of local optical spectroscopy in quantum wires taking into account structural disorder. The calculated spatially resolved spectra show the individual spectral lines due to the exciton states localized by the disordered potential in agreement with experimental findings.We investigate systematically the influence of the potential profile and of the spatial resolution on the local optical spectra. Several line scans along the wire axis are obtained for different spatial correlations and strength of the disorder potential and for different spatial resolutions ranging from the subwavelength to the diffraction limit. Lowering the spatial resolution causes the disappearance of many spectral lines due to destructive spatial interference. However, our results show that information on the individual eigenstates of this quasi one-dimensional quantum system can be obtained at also resolutions significantly lower than the correlation length of interface fluctuations
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