Search results for "cavity quantum electrodynamic"
showing 10 items of 70 documents
Simulating open quantum systems with trapped ions
2005
This paper focuses on the possibility of simulating the open system dynamics of a paradigmatic model, namely the damped harmonic oscillator, with single trapped ions. The key idea consists in using a controllable physical system, i.e. a single trapped ion interacting with an engineered reservoir, to simulate the dynamics of other open systems usually difficult to study. The exact dynamics of the damped harmonic oscillator under very general conditions is firstly derived. Some peculiar characteristic of the system’s dynamics are then presented. Finally a way to implement with trapped ion the specific quantum simulator of interest is discussed.
Elements of Quantum Electrodynamics and Weak Interactions
2013
Quantum field theory in its application to electroweak and strong interactions has two rather different facets: A pragmatic, empirical one, and an algebraic, systematical one. The pragmatic approach consists in a set of rules and formal calculational procedures which are extremely successful in their application to concrete physical processes, but rest on mathematically shaky ground. The mathematically rigorous approach, in turn, is technically difficult and not very useful, from a practical point of view, for reaching results which can be compared with phenomenology. Generally speaking, quantum field theory quickly becomes rather technical if one wants to understand it in some depth, and g…
Efficient generation of N-photon binomial states and their use in quantum gates in cavity QED
2010
A high-fidelity scheme to generate N-photon generalized binomial states (NGBSs) in a single-mode high-Q cavity is proposed. A method to construct superpositions of exact orthogonal NGBSs is also provided. It is then shown that these states, for any value of N, may be used for a realization of a controlled-NOT gate, based on the dispersive interaction between the cavity field and a control two-level atom. The possible implementation of the schemes is finally discussed.
Observation of high-purity single photons hopping between optical cavities
2014
We experimentally demonstrate high-purity single photons hopping coherently between coupled optical cavities. The system shows high performance also as a controllable single-photon source, which emits single photons with a negative Wigner function.
Bell's inequality violation for entangled generalized Bernoulli states in two spatially separate cavities
2005
We consider the entanglement of orthogonal generalized Bernoulli states in two separate single-mode high-$Q$ cavities. The expectation values and the correlations of the electric field in the cavities are obtained. We then define, in each cavity, a dichotomic operator expressible in terms of the field states which can be, in principle, experimentally measured by a probe atom that ``reads'' the field. Using the quantum correlations of couples of these operators, we construct a Bell's inequality which is shown to be violated for a wide range of the degree of entanglement and which can be tested in a simple way. Thus the cavity fields directly show quantum non-local properties. A scheme is als…
Validating and controlling quantum enhancement against noise by motion of a qubit
2019
Experimental validation and control of quantum traits for an open quantum system are important for any quantum information purpose. We consider a traveling atom qubit as a quantum memory with adjustable velocity inside a leaky cavity, adopting a quantum witness as a figure of merit for quantumness assessment. We show that this model constitutes an inherent physical instance where the quantum witness does not work properly if not suitably optimized. We then supply the optimal intermediate blind measurements which make the quantum witness a faithful tester of quantum coherence. We thus find that larger velocities protect quantumness against noise, leading to lifetime extension of hybrid qubit…
Quantum Computation with Generalized Binomial States in Cavity Quantum Electrodynamics
2008
We study universal quantum computation in the cavity quantum electrodynamics (CQED) framework exploiting two orthonormal two-photon generalized binomial states as qubit and dispersive interactions of Rydberg atoms with high-$Q$ cavities. We show that an arbitrary qubit state may be generated and that controlled-NOT and 1-qubit rotation gates can be realized via standard atom-cavity interactions.
Non-classicality of optomechanical devices in experimentally realistic operating regimes
2013
Enforcing a non-classical behavior in mesoscopic systems is important for the study of the boundaries between quantum and classical world. Recent experiments have shown that optomechanical devices are promising candidates to pursue such investigations. Here we consider two different setups where the indirect coupling between a three-level atom and the movable mirrors of a cavity is achieved. The resulting dynamics is able to conditionally prepare a non-classical state of the mirrors by means of projective measurements operated over a pure state of the atomic system. The non-classical features are persistent against incoherent thermal preparation of the mechanical systems and their dissipati…
Dressed states of a quantum emitter strongly coupled to a metal nanoparticle
2016
Hybrid molecule-plasmonic nanostructures have demonstrated their potential for surface enhanced spectroscopies, sensing, or quantum control at the nanoscale. In this Letter, we investigate the strong coupling regime and explicitly describe the hybridization between the localized plasmons of a metal nanoparticle and the excited state of a quantum emitter, offering a simple and precise understanding of the energy exchange in full analogy with cavity quantum electrodynamics treatment and a dressed atom picture. Both near-field emission and far-field radiation are discussed, revealing the richness of such optical nanosources.
Cavity QED of a leaky planar resonator coupled to an atom and an input single-photon pulse
2013
In contrast to the free-space evolution of an atom governed by a multi-mode interaction with the surrounding electromagnetic vacuum, the evolution of a cavity-QED system can be characterized by just three parameters, (i) atom-cavity coupling strength g, (ii) cavity relaxation rate \kappa, and (iii) atomic decay rate into the non-cavity modes \gamma. In the case of an atom inserted into a planar resonator with an input beam coupled from the outside, it has been shown by Koshino [Phys. Rev. A 73, 053814 (2006)] that these three parameters are determined not only by the atom and cavity characteristics, but also by the spatial distribution of the input pulse. By an ab-initio treatment, we gener…