Browsing Agarwal, Girish by Title
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Cavitymediated longrange interaction for fast multiqubit quantum logic operations
(Physical Review A, 20051105)Interactions among qubits are essential for performing twoqubit quantum logic operations. However, nature gives us only nearest neighbor interactions in simple and controllable settings. Here we propose a strategy to ... 
Competition between electromagnetically induced transparency and Raman processes
(Physical Review A, 20061005)We present a theoretical formulation of competition among electromagnetically induced transparency (EIT) and Raman processes. The latter become important when the medium can no longer be considered to be dilute. Unlike the ... 
DC field induced enhancement and inhibition of spontaneous emission in a cavity
(Physical Review A, 20040820)We demonstrate how spontaneous emission in a cavity can be controlled by the application of a dc field. The method is specially suitable for Rydberg atoms. We present a simple argument based on Stark shifts for the control ... 
Electromagnetic field induced modification of branching ratios for emission in structured vacuum
(New Journal of Physics, 20080117)We report a fundamental effect of the electromagnetic field induced modification of the branching ratios for emission into several final states. The modifications are especially significant if the vacuum into which the ... 
Electromagnetically induced magnetochiral anisotropy in a resonant medium
(Physical Review Letters, 20050714)Chirality has been extensively studied for well over a century, and its potential applications range from optics to chemistry, medicine, and biology. Ingenious experiments have been designed to measure this naturally small ... 
Entanglement by linear SU(2) transformations: generation and evolution of quantum vortex states
(Journal of Physics A: Mathematical and General, 20060731)We consider the evolution of a twomode system of bosons under the action of a Hamiltonian that generates linear SU(2) transformations. The Hamiltonian is generic in that it represents a host of entanglement mechanisms, ... 
Entanglement of two distant BoseEinstein condensates by detection of Braggscattered photons
(Physical Review A, 20080731)We show that it is possible to generate entanglement between two distant BoseEinstein condensates by detection of Hanbury BrownTwiss type correlations in photons Braggscattered by the condensates. Upon coincident detection ... 
Entangling pairs of nanocantilevers, Cooperpair boxes and mesoscopic teleportation
(New Journal of Physics, 20060307)We propose two schemes to establish entanglement between two mesoscopic quantum systems through a third mesoscopic quantum system. The first scheme entangles two nanomechanical oscillators in a nonGaussian entangled state ... 
Extreme subwavelength atom localization via coherent population trapping
(Journal of Physics B: Atomic, Molecular and Optical Physics, 20060906)We demonstrate an atom localization scheme based on monitoring of the atomic coherences. We consider atomic transitions in a Lambda configuration where the control field is a standingwave field. The probe field and the ... 
Fast light solitons in resonant media
(Physical Review A, 20070405)Using the structure of the MaxwellSchrodinger equations in twolevel systems in the transient domain, we derive both singlesoliton and multisoliton (2n pi pulse) solutions associated with fast light in resonant media. ... 
Generation of a superposition of multiple mesoscopic states of radiation in a resonant cavity
(Physical Review A, 20050627)Using resonant interaction between atoms and the field in a high quality cavity, we show how to generate a superposition of many mesoscopic states of the field. We study the quasiprobability distributions and demonstrate ... 
Generation of Werner states via collective decay of coherently driven atoms
(Physical Review A, 20060308)We show deterministic generation of Werner states as a steady state of the collective decay dynamics of a pair of neutral atom coupled to a leaky cavity and strong coherent drive. We also show how the scheme can be extended ... 
Implementing DeutschJozsa algorithm using light shifts and atomic ensembles
(Physical Review A, 20050127)We present an optical scheme to implement the DeutschJozsa algorithm using ac Stark shifts. The scheme uses an atomic ensemble consisting of fourlevel atoms interacting dispersively with a field. This leads to a Hamiltonian ... 
Inducing disallowed twoatom transitions with temporally entangled photons
(Physical Review Letters, 20040825)Two uncoupled twolevel atoms cannot be jointly excited by classical light under general circumstances, due to destructive interference of excitation pathways in twophoton absorption. However, with temporally entangled ... 
Inseparability inequalities for higher order moments for bipartite systems
(New Journal of Physics, 20051007)There are several examples of bipartite entangled states of continuous variables for which the existing criteria for entanglement using the inequalities involving the secondorder moments are insufficient. We derive new ... 
Interferences in parametric interactions driven by quantized fields
(Physical Review Letters, 20060711)We report interferences in the quantum fluctuations of the output of a parametric amplifier when the cavity is driven by a quantized field at the signal frequency. The interferences depend on the phase fluctuations of the ... 
Langevin analysis of fundamental noise limits in coherent antiStokes Raman spectroscopy
(Physical Review A, 20050104)We use a Langevin approach to analyze the quantum noise in coherent antiStokes Raman spectroscopy in several experimental scenarios: with continuouswave input fields acting simultaneously and with fast sequential pulsed ... 
Large two atom two photon vacuum Rabi oscillations in a high quality cavity
(Physical Review A, 20041011)We predict large cooperative effect involving two atom two photon vacuum Rabi oscillations in a high quality cavity. 
Laser induced resonance shifts of single molecules selfcoupled by a metallic surface
(Physical Review Letters, 20070405)The spectral properties of single molecules placed near a metallic surface are investigated at low temperatures. Because of the high quality factor of the optical resonance, a laser induced shift of the molecular lines is ... 
Measurementinduced spatial modulation of spontaneous decay and photon arrival times
(Physical Review A, 20061220)We report a way of manipulating the spontaneous emission process leading to a spatial modulation of spontaneous decay. The effect is observed in the case of coherently driven atoms separated by less than a transition ...