13 research outputs found
Maximal correlation between flavor entanglement and oscillation damping due to localization effects
Localization effects and quantum decoherence driven by the mass-eigenstate
wave packet propagation are shown to support a statistical correlation between
quantum entanglement and damped oscillations in the scenario of three-flavor
quantum mixing for neutrinos. Once the mass-eigenstates that support flavor
oscillations are identified as three-{\em qubit} modes, a decoherence scale can
be extracted from correlation quantifiers, namely the entanglement of formation
and the logarithmic negativity. Such a decoherence scale is compared with the
coherence length of damped oscillations. Damping signatures exhibited by flavor
transition probabilities as an effective averaging of the oscillating terms are
then explained as owing to loss of entanglement between mass modes involved in
the relativistic propagation.Comment: 13 pages, 03 figure
Generating long-lived entangled states with free-space collective spontaneous emission
International audienceConsidering the paradigmatic case of a cloud of two-level atoms interacting through common vacuum modes, we show how cooperative spontaneous emission, which is at the origin of superradiance, leads the system to long-lived entangled states at late times. These subradiant modes are characterized by an entanglement between all particles, independently of their geometrical configuration. While there is no threshold on the interaction strength necessary to entangle all particles, stronger interactions lead to longer-lived entanglement
Steady-state entanglement generation for non-degenerate qubits
We propose a scheme to dissipatively produce steady-state entanglement in a
two-qubit system, via an interaction with a bosonic mode. The system is driven
into a stationary entangled state, while we compensate the mode dissipation by
injecting energy via a coherent pump field. We also present a scheme which
allows us to adiabatically transfer all the population to the desired entangled
state. The dynamics leading to the entangled state in these schemes can be
understood in analogy with electromagnetically induced transparency (EIT) and
stimulated Raman adiabatic passage (STIRAP), respectively.Comment: 7 pages, 4 figure
Electromagnetically Induced Transparency with Single Atoms in a Cavity
Optical nonlinearities offer unique possibilities for the control of light
with light. A prominent example is electromagnetically induced transparency
(EIT) where the transmission of a probe beam through an optically dense medium
is manipulated by means of a control beam. Scaling such experiments into the
quantum domain with one, or just a few particles of both light and matter will
allow for the implementation of quantum computing protocols with atoms and
photons or the realisation of strongly interacting photon gases exhibiting
quantum phase transitions of light. Reaching these aims is challenging and
requires an enhanced matter-light interaction as provided by cavity quantum
electrodynamics (QED). Here we demonstrate EIT with a single atom
quasi-permanently trapped inside a high-finesse optical cavity. The atom acts
as a quantum-optical transistor with the ability to coherently control the
transmission of light through the cavity. We furthermore investigate the
scaling of EIT when the atom number is increased one by one. The measured
spectra are in excellent agreement with a theoretical model. Merging EIT with
cavity QED and single quanta of matter is likely to become the cornerstone for
novel applications, e.g. the dynamic control of the photon statistics of
propagating light fields or the engineering of Fock-state superpositions of
flying light pulses.Comment: 6 pages, 4 figure