Search results for "quantum optic"
showing 10 items of 153 documents
Manifestation of Curie-Weiss law for optical phase transition
2001
Considerable slowing down is observed for both the temporal development of the coherent oscillation slightly above the threshold and the refractive index grating decay slightly below the threshold for a semilinear photorefractive oscillator with two counter-propagating pump waves. It is shown that in the vicinity of the threshold the reciprocal characteristic time is a linear function of deviation from the threshold coupling strength. This behaviour is similar to an empirical Curie–Weiss law and points to the analogy of the oscillation threshold to a second-order phase transition.
Entanglement of distant superconducting quantum interference device rings
2005
We consider two distant mesoscopic SQUID rings, approximated with two-level systems, interacting with two-mode microwaves. The Hamiltonian of the system is used to calculate its time evolution. The cases with microwaves which at t = 0 are in separable states (classically correlated) or entangled states (quantum mechanically correlated) are studied. It is shown that the Josephson currents in the two SQUID rings are also correlated.
Motion of the wave-function zeros in spin-boson systems.
1995
In the analytic Bargmann representation associated with the harmonic oscillator and spin coherent states, the wave functions considered as consisting of entire complex functions can be factorized in terms of their zeros in a unique way. The Schr\"odinger equation of motion for the wave function is turned to a system of equations for the zeros of the wave function. The motion of these zeros as a nonlinear flow of points is studied and interpreted for linear and nonlinear bosonic and spin Hamiltonians. Attention is given to the study of the zeros of the Jaynes-Cummings model and to its finite analog. Numerical solutions are derived and dicussed.
Stimulated emission control in Photonic Crystals: Strong coupling regime in QNM approach
2006
Stimulated emission, in strong coupling regime, in a one dimensional photonic crystals is described by considering two counter-propagating pumps. Quasi normal mode approach is used and coherent control of the Rabi splitting is discussed.
Acousto-electric single-photon detector
2007
We propose a novel concept for a semiconductor-based single-photon detector for quantum information processing, which is capable of discriminating the number of photons in a light pulse. The detector exploits the charge transport by a surface acoustic wave (SAW) in order to combine a large photon absorption area (thus providing high photon collection efficiency) with a microscopic charge detection area, where the photo generated charge is detected with resolution at the single electron level using single electron transistors (SETs). We present preliminary results on acoustic transport measured in a prototype for the detector as well as on the fabrication of radio-frequency single-electron t…
Quantum fluctuations in cavity solitons
2005
Quantum fluctuations of degenerate optical parametric oscillators' cavity solitons (CS) are studied. We show that CSs are sources of perfectly squeezed light that exhibit photon fluctuations below the shot-noise level as well.
Integrated generation of complex optical quantum states and their coherent control
2018
Complex optical quantum states based on entangled photons are essential for investigations of fundamental physics and are the heart of applications in quantum information science. Recently, integrated photonics has become a leading platform for the compact, cost-efficient, and stable generation and processing of optical quantum states. However, onchip sources are currently limited to basic two-dimensional (qubit) two-photon states, whereas scaling the state complexity requires access to states composed of several (<2) photons and/or exhibiting high photon dimensionality. Here we show that the use of integrated frequency combs (on-chip light sources with a broad spectrum of evenly-spaced fre…
Distortion of the virtual photon cloud due to a static electric field
1988
The structure of the virtual transverse-photon cloud surrounding a ground-state hydrogen atom is considered in the presence of a uniform static electric field, which is capable of polarizing the atom. It is shown that this virtual cloud is distorted with respect to the spherically symmetric shape which is obtained when no static electric field is present. The distortion is carried by new components of the cloud, arising from the contributions of magnetic-dipole and electric-quadrupole virtual photons. These new contributions are shown to possess an overall cylindrical symmetry around the direction of the static field, and to be present also at large distances from the atom. The possibility …
Observation of instabilities in a Paul trap with higher-order anharmonicities
1995
Systematic measurements of the relative ion number stored in a Paul trap within the stability diagram given by the solution of the equation of motion reveal many lines, where only few or no ions can be confined. The observations can be explained by the presence of perturbations from higher-order components in the trapping potential, which is a quadrupole potential in the ideal case. The resonances follow the equation (nr/2)βr + (nr/2)βz = 1,nr +nz =N, where 2N is the order of the perturbation,nr,nz are integer andβr,βz are stability parameters of the trap. The experiments were performed on H+ and H2+ ions, which are detected after a storage time of 0.3 s by ejection from the trap.
A test of special relativity with stored lithium ions
1993
Laser spectroscopy at the heavy ion storage ring TSR in Heidelberg allows for precision experiments testing the limits of the special theory of relativity. With an opticalΛ-type three-level system of7Li+ the Doppler shift has been measured by saturation spectroscopy as a test of the time dilatation factor γ = (1 −β2)−1/2 at an ion velocity ofυ = 6.4% c. A precision ofΔν/ν < 9 × 10−9 has been obtained, which sets a second-order limit of 1.1 × 10−6 for any deviation from the time dilatation factor. The fourth-order limit of this deviation is set below 2.7 × 10−4 by the present experiment. These limits are given at a 1 σ confidence level.