Search results for "Coherence"
showing 10 items of 905 documents
Theoretical analysis of a recent experiment on mesoscopic state superpositions in cavity QED
2005
Quite recently quantum features exhibited by a mesoscopic field interacting with a single Rydberg atom in a microwave cavity has been observed [A. Auffeves et al., Phys. Rev. Lett. 91, 230405 (2003)]. In this paper we theoretically analyze all the phases of this articulated experiment considering from the very beginning cavity losses. Fully applying the theory of quantum open systems, our modelization succeeds in predicting fine aspects of the measured quantity, reaching qualitative and quantitative good agreement with the experimental results. This fact validates our theoretical approach based on the fundamental atom-cavity interaction model and simple mathematical structure of dissipative…
Hilbert-Huang single-shot spatially multiplexed interferometric microscopy.
2018
Hilbert-Huang single-shot spatially multiplexed interferometric microscopy (H2S2MIM) is presented as the implementation of a robust, fast, and accurate single-shot phase estimation algorithm with an extremely simple, low-cost, and highly stable way to convert a bright field microscope into a holographic one using partially coherent illumination. Altogether, H2S2MIM adds high-speed (video frame rate) quantitative phase imaging capability to a commercially available nonholographic microscope with improved phase reconstruction (coherence noise reduction). The technique has been validated using a 20×/0.46 NA objective in a regular Olympus BX-60 upright microscope for static, as well as dynamic…
Generation of two-mode quantum states of light with timing controllable memories
2020
We created and experimentally verified two-mode entangled states of light, α|0,1⟩ + βe*+|1,0⟩, by means of two phase-sensitive optical quantum memories. The release timing of each optical mode can be independently controlled for up to 400 ns.
Ultrafast collisional dissipation of symmetric-top molecules probed by rotational alignment echoes
2020
We experimentally and theoretically investigate the ultrafast collisional dynamics of a symmetric-top molecule (${\mathrm{C}}_{2}{\mathrm{H}}_{6}$) in pure gas and mixtures with He at high density by employing the rotational alignment echo created by a pair of time-delayed intense laser kicks. The decrease of the amplitude of the echo when increasing the delay between the two laser pulses, reflecting the collisional relaxation of the system, is measured by probing the transient birefringence induced in the medium. The theoretical predictions, carried using purely classical molecular dynamics simulations, reproduce well the observed features, as demonstrated previously for a linear molecule.…
Experimental recovery of quantum correlations in absence of system-environment back-action
2013
Revivals of quantum correlations in composite open quantum systems are a useful dynamical feature against detrimental effects of the environment. Their occurrence is attributed to flows of quantum information back and forth from systems to quantum environments. However, revivals also show up in models where the environment is classical, thus unable to store quantum correlations, and forbids system-environment back-action. This phenomenon opens basic issues about its interpretation involving the role of classical environments, memory effects, collective effects and system-environment correlations. Moreover, an experimental realization of back-action-free quantum revivals has applicative rele…
X-shaped space-time coherence in optical parametric generation
2007
We study the spatiotemporal coherence properties of superfluorescence radiation generated in optical parametric amplification of quantum noise. We show that the angular dispersion properties of the spatiotemporal spectra, measured in different phase-matching conditions, lead to a clear X-shaped structure of the mutual correlation function of the radiation. Within a statistical picture, we interpret the generated superfluorescence as a stochastic “gas” of quasistationary modes characterized by a skewed correlation in the spatiotemporal domain, with characteristics similar to linear and nonlinear X waves not describable within a separable approach in space and time.
On the observability of parity and time reversal violating interactions by trapped ion spectroscopy
1982
The feasibility to measure neutral weak current interactions by spectroscopy on trapped ions is investigated. The sensitivity of the proposed experiment is compared to the sensitivity of similar experiments using atomic gases or beams. It is shown that there is no advantage as far as that part of the interaction is concerned which is a vector in the nucleon current and an axial vector in the electron current. This is mainly due to the relatively low ion density. The circular polarization however depending upon the nuclear spin orientation appears to be proportional to the coherence time, which is three orders of magnitude longer than in ordinary atomic beam resonance experiments. It is poin…
Measurement of in oscillation using quantum correlations in at
2015
We report a measurement of the parameter y(CP) in D-0-(D) over bar (0) oscillations performed by taking advantage of quantum coherence between pairs of D-0(D) over bar (0) mesons produced in e(+)e(-) annihilations near threshold. In this work, doubly-tagged D-0(D) over bar (0) events, where one D decays to a CP eigenstate and the other D decays in a semileptonic mode, are reconstructed using a data sample of 2.92 fb(-1) collected with the BESIII detector at the center-of-mass energy of root s = 3.773 GeV. We obtain y(CP) = (-2.0 +/- 1.3 +/- 0.7)%, where the first uncertainty is statistical and the second is systematic. This result is compatible with the current world average.
CPT violation in entangled B0–B¯0 states and the demise of flavour tagging
2005
Abstract We discuss the demise of flavour tagging due to the loss of the particle–antiparticle identity of neutral B -mesons in the Einstein–Podolsky–Rosen correlated states. Such a situation occurs in cases where the CPT operator is ill-defined, as happens, for example, in quantum gravity models with induced decoherence in the matter sector. The time evolution of the perturbed B 0 – B ¯ 0 initial state, as produced in B -factories, is sufficient to generate new two-body states. For flavour specific decays at equal times, we discuss two definite tests of the two body entanglement: (i) search for the would-be forbidden B 0 B 0 and B ¯ 0 B ¯ 0 states; (ii) deviations from the indistinguishabl…
CPT Violating Decoherence and LSND: a possible window to Planck scale Physics
2004
Decoherence has the potential to explain all existing neutrino data including LSND results, without enlarging the neutrino sector. This particular form of CPT violation can preserve the equality of masses and mixing angles between particle and antiparticle sectors, and still provide seizable differences in the oscillation patterns. A simplified minimal model of decoherence is sufficient to explain the existing neutrino data quite neatly, while making dramatic predictions for the upcoming experiments. Some comments on the order of the decoherence parameters in connection with theoretically expected values from some models of quantum-gravity are given. In particular, the quantum gravity decoh…