Enhancement of Cavity Cooling of a Micromechanical Mirror Using Parametric Interactions (2008)
It is shown that an optical parametric amplifier inside a cavity can considerably improve the cooling of the micromechanical mirror by radiation pressure. The micromechanical mirror can be cooled...
Multipartite Entanglement Criterion from Uncertainty Relations (2008)
Gillet, J., Bastin, T., Agarwal, G. S.
We formulate an entanglement criterion using Peres-Horodecki positive partial transpose operations combined with the Schr\"odinger-Robertson uncertainty relation. We show that any pure entangled...
Nonclassical Correlation of Polarization Entangled Photons in a Biexciton-Exciton Cascade (2008)
We develop a theoretical model to study the Intensity-Intensity correlation of polarization entangled photons emitted in a biexciton-exciton cascade. We calculate the degree of correlation and show...
Quantum Interferences in Cooperative Dicke Emission from Spatial Variation of Laser Phase (2008)
Das, Sumanta, Agarwal, G. S., Scully, Marlan O.
We report generation of a new quantum interference effect in spontaneous emission from a resonantly driven system of two identical two-level atoms due to the spatial variation of the laser phase at...
Transport and Quantum Walk of Nonclassical Light in Coupled Waveguides (2008)
Rai, Amit, Agarwal, G. S., Perk, J. H. H.
We study the transport and quantum walk of nonclassical light in an array of coupled waveguides which have novel properties like very low decoherence and thus making them ideal for storage of quantum...
Sub-Rayleigh Quantum Imaging Using Single Photon Sources (2008)
Thiel, C., Bastin, T., Von Zanthier, J., Agarwal, G. S.
We propose a technique capable of imaging a distinct physical object with sub-Rayleigh resolution in an ordinary far-field imaging setup using single-photon sources and linear optical tools only. We...
Quantum interferometry using coherent beam stimulated parametric down-conversion (2008)
Kolkiran, Aziz, Agarwal, G. S.
We show how stimulated parametric processes can be employed in experiments on beyond the diffraction limit to overcome the problem of low visibility obtained by using spontaneous down conversion...
Entanglement of two distant Bose-Einstein condensates by detection of Bragg-scattered photons (2008)
We show that it is possible to generate entanglement between two distant Bose-Einstein condensates by detection of Hanbury Brown-Twiss type correlations in photons Bragg-scattered by the condensates....
A Quantum Optical Spring (2008)
We study the dynamics of the quantum optical spring, i.e., a spring whose spring constant undergoes discreet jumps depending on the quantum state of another system. We show the existence of revivals...
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...
Photon-Photon Correlations as a Probe of Vacuum Induced Coherence Effects (2007)
We present new experimental implications of the effects of vacuum induced coherence on the photon -photon correlation in the pi-polarized fluorescence in j = 1/2 to j = 1/2 transition. These effects...
Operational monitoring of multi-qubit entanglement classes via tuning of local operations (2007)
Bastin, T., Thiel, C., Von Zanthier, J., Lamata, L., Solano, E., Agarwal, G. S.
Entanglement is a distinctive property of quantum physics associated with the nonseparable character of multipartite quantum systems. For the case of two-qubit systems, entanglement is well...
Solitons in interacting Dicke models of coupled cavities with two-level systems (2007)
Paternostro, M., Agarwal, G. S., Kim, M. S.
We consider an array of coupled optical cavities, each containing a multi-atom ensemble. We show that the nonlinearity inherent in the cooperative dynamics of the atoms in each ensemble coupled to...
Heisenberg limited Sagnac interferometry (2007)
We show how the entangled photons produced in parametric down conversion can be used to improve the sensitivity of a Sagnac interferometer. Two-photon and four-photon coincidences increases the...
Laser induced resonance shifts of single molecules self-coupled by a metallic surface (2007)
Labeau, O., Tamarat, Ph., Courtois, Hervé, Agarwal, G. S., Lounis, B.
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...
Laser induced resonance shifts of single molecules self-coupled by a metallic surface (2007)
Labeau, O., Tamarat, Ph., Courtois, Hervé, Agarwal, G. S., Lounis, B.
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...
Generation of Symmetric Dicke States of Remote Qubits with Linear Optics (2007)
Thiel, C., Von Zanthier, J., Bastin, T., Solano, E., Agarwal, G. S.
We propose a method for generating all symmetric Dicke states, either in the long-lived internal levels of N massive particles or in the polarization degrees of freedom of photonic qubits, using...
Quantum Imaging with Incoherent Photons (2007)
Thiel, C., Bastin, T., Martin, J., Solano, E., Von Zanthier, J., Agarwal, G. S.
We propose a technique to obtain sub-wavelength resolution in quantum imaging with potentially 100% contrast using incoherent light. Our method requires neither path-entangled number states nor...
Realization of quantum mechanical weak values of observables using entangled photons (2006)
We present a scheme for realization of quantum mechanical weak values of observables using entangled photons produced in parametric down conversion. We consider the case when the signal and idler...
Nonclassicality and decoherence of photon-subtracted squeezed states (2006)
We discuss nonclassical properties of single-photon subtracted squeezed vacuum states in terms of the sub-Poissonian statistics and the negativity of the Wigner function. We derive a compact...
Quantum Properties of a Nanomechanical Oscillator (2006)
Kolkiran, Aziz, Agarwal, G. S.
We study the quantum properties of a nanomechanical oscillator via the squeezing of the oscillator amplitude. The static longitudinal compressive force $F_0$ close to a critical value at the Euler...
We consider the evolution of a two-mode 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...
Competition between Electromagnetically Induced Transparency and Raman Processes (2006)
Agarwal, G. S., Dey, T. N., Gauthier, Daniel J.
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...
Towards Heisenberg Limit in Magnetometry with Parametric Down Converted Photons (2006)
Kolkiran, Aziz, Agarwal, G. S.
Recent theoretical and experimental papers have shown how one can achieve Heisenberg limited measurements by using entangled photons. Here we show how the photons in non-collinear down conversion...
Quantum random walk of two photons in separable and entangled state (2006)
We discuss quantum random walk of two photons using linear optical elements. We analyze the quantum random walk using photons in a variety of quantum states including entangled states. We find that...
Two-bit Deutsch-Jozsa algorithm using an atomic ensemble (2006)
Dasgupta, Shubhrangshu, Agarwal, G. S.
The first optical proposal for the realization of the two-bit version of the Deutsch-Jozsa algorithm [D. Deutsch and R. Jozsa, Proc. R. Soc. London A {\bf 493}, 553 (1992)] is presented. The proposal...
Haas, M., Jentschura, U. D., Keitel, C. H., Kolachevsky, Nikolai, Herrmann, Maximilian, Fendel, Peter, ...
Haas, Martin, Jentschura, Ulrich David, Keitel, Christoph Helmut, Kolachevsky, N., Herrmann, M., Fendel, P., ...
One of the dominant systematic effects that shift resonance lines in high-precision measurements of two-photon transitions is the dynamic (ac) Stark shift. For suitable laser frequencies, the ac...
A new class of exact solitary wave solutions of one dimensional Gross-Pitaevskii equation (2005)
Atre, Rajneesh, Panigrahi, Prasanta K., Agarwal, G. S.
We present a large family of {\it{exact}} solitary wave solutions of the one dimensional Gross-Pitaevskii equation, with time-varying scattering length and gain/loss, in both expulsive and regular...
Ultraslow light in inhomogeneously broadened media (2005)
We calculate the characteristics of ultraslow light in an inhomogeneously broadened medium. We present analytical and numerical results for the group delay as a function of power of the propagating...
Entangling Pairs of Nano-Cantilevers, Cooper-Pair Boxes and Mesoscopic Teleportation (2005)
We propose two schemes to establish entanglement between two mesoscopic quantum systems through a third mesoscopic quantum system. The first scheme entangles two nano-mechanical oscillators in a...
N-qubit quantum memory through a well-defined sequence of optical pulses (2005)
Kapale, Kishor T., Agarwal, G. S., Scully, M. O.
NASA
Inseparability inequalities for higher-order moments for bipartite systems (2005)
There are several examples of bipartite entangled states of continuous variables for which the existing criteria for entanglement using the inequalities involving the second order moments are...
Quantum random walk of the field in an externally driven cavity (2005)
Using resonant interaction between atoms and the field in a high quality cavity, we show how to realize quantum random walks as proposed by Aharonov et al [Phys. Rev. A {\bf48}, 1687 (1993)]. The...
Quantitative measures of entanglement in pair coherent states (2005)
The pair coherent states for a two-mode radiation field are known to belong to a family of states with non-Gaussian wave function. The nature of quantum entanglement between the two modes and some...
Generation of a superposition of multiple mesoscopic states of radiation in a resonant cavity (2004)
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 quasi-probability...
A collective system of atoms in a high quality cavity can be described by a nonlinear interaction which arises due to the Lamb shift of the energy levels due to the cavity vacuum [Agarwal et al.,...
Causality in Propagation of a Pulse in a Nonlinear Dispersive Medium (2004)
Agarwal, G. S., Dey, Tarak Nath
We investigate the causal propagation of the pulse through dispersive media by very precise numerical solution of the coupled Maxwell-Bloch equations without any approximations about the strength of...
A Langevin analysis of fundamental noise limits in Coherent Anti-Stokes Raman Spectroscopy (2004)
Das, Kunal K., Agarwal, G. S., Golubev, Yu. M., Scully, M. O.
We use a Langevin approach to analyze the quantum noise in Coherent Anti-Stokes Raman Spectroscopy (CARS) in several experimental scenarios: with continuous wave input fields acting simultaneously...
Large two-atom two-photon vacuum Rabi oscillations in a high quality cavity (2004)
We predict large cooperative effect involving two atom two photon vacuum Rabi oscillations in a high quality cavity. The two photon emission occurs as a result of simultaneous de-excitation of both...
Quantum holography and multiparticle entanglement using ground-state coherences (2004)
Agarwal, G. S., Lougovski, P., Walther, H.
A method of storing and retrieving quantum states of radiation fields using the ground-state coherences is discussed. We demonstrate the generation of multiparticle entangled states starting from...
Nanosecond Dynamics of Single-Molecule Fluorescence Resonance Energy Transfer (2004)
Ariunbold, G. O., Agarwal, G. S., Wang, Z., Walther, H., Scully, M. O.
Motivated by recent experiments on photon statistics from individual dye pairs planted on biomolecules and coupled by fluorescence resonance energy transfer (FRET), we show here that the FRET...
Nonclassical Imaging for a quantum search of trapped ions (2004)
Agarwal, G. S., Ariunbold, G. O., Von Zanthier, J., Walther, H.
We discuss a simple search problem which can be pursued with different methods, either on a classical or on a quantum basis. The system is represented by a chain of trapped ions. The ion to be...
Quantum logic gates using Stark shifted Raman transitions in a cavity (2004)
We present a scheme to realise the basic two-quibit logic gates such as quantum phase gate and controlle-NOT gate using a detuned optical cavity interacting with a three-level Raman system. We...
DC field induced enhancement and inhibition of spontaneous emission in a cavity (2003)
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 for the...
Mesoscopic Superposition of States with Sub-Planck Structures in Phase Space (2003)
We propose a method using the dispersive interaction between atoms and a high quality cavity to realize the mesoscopic superposition of coherent states which would exhibit sub-Planck structures in...
Preparation of W, GHZ, and two-qutrit states using bimodal cavities (2003)
We show how one can prepare three-qubit entangled states like W states, Greenberger-Horne-Zeilinger states as well as two-qutrit entangled states using the multiatom two-mode entanglement. We propose...
Slow Light in Doppler Broadened Two level Systems (2003)
Agarwal, G. S., Dey, Tarak Nath
We show that the propagation of light in a Doppler broadened medium can be slowed down considerably eventhough such medium exhibits very flat dispersion. The slowing down is achieved by the...
We develop models for the propagation of intense pulses in solid state media which can have either saturated absorption or exhibit reverse absorption . We show that the experiments of Bigelow {\it et...
Strong subadditivity inequality for quantum entropies and four-particle entanglement (2003)
Strong subadditivity inequality for a three-particle composite system is an important inequality in quantum information theory which can be studied via a four-particle entangled state. We use two...
Transfer of an unknown quantum state, quantum networks, and memory (2003)
We present a protocol for transfer of an unknown quantum state. The protocol is based on a two-mode cavity interacting dispersively in a sequential manner with three-level atoms in $\Lambda$...
Agarwal, G. S., Dasgupta, Shubhrangshu
We calculate magneto-optical rptation of spectrally impure fileds in an optically thick cold atmic medium. We show that the spectral impurity leads to non-linear dependence of the rotation angle on...
Influence of damping on the vanishing of the electro-optic effect in chiral isotropic media (2002)
Agarwal, G. S., Boyd, Robert W.
Using first principles, it is demonstrated that radiative damping alone cannot lead to a nonvanishing electro-optic effect in a chiral isotropic medium. This conclusion is in contrast with that...
Existence of superposition solutions for pulse propagation in nonlinear resonant media (2002)
Panigrahi, P. K., Agarwal, G. S.
Existence of self-similar, superposed pulse-train solutions of the nonlinear, coupled Maxwell-Schr\"odinger equations, with the frequencies controlled by the oscillator strengths of the transitions,...
From Storage and Retrieval of Pulses to Adiabatons (2002)
Dey, Tarak Nath, Agarwal, G. S.
We investigate whether it is possible to store and retrieve the intense probe pulse from a $\Lambda$-type homogeneous medium of cold atoms. Through numerical simulations we show that it is possible...
Arbitrary qubit rotation through nonadiabatic evolution (2002)
We show how one can perform arbitrary rotation of any qubit, using delayed laser pulses through nonadiabatic evolution, i.e., via transitions among the adiabatic states. We use a double-Lambda scheme...
Single Atom and Two Atom Ramsey Interferometry with Quantized Fields (2002)
Agarwal, G. S., Pathak, P. K., Scully, M. O.
Implications of field quantization on Ramsey interferometry are discussed and general conditions for the occurrence of interference are obtained. Interferences do not occur if the fields in two...
Entangling Two Bose-Einstein Condensates by Stimulated Bragg Scattering (2002)
We propose an experiment for entangling two spatially separated Bose-Einstein condensates by Bragg scattering of light. When Bragg scattering in two condensates is stimulated by a common probe, the...
Agarwal, G. S., Dasgupta, Shubhrangshu
We show how a medium, under the influece of a coherent control field which is resonant or close to resonance to an appropriate atomic transition, can lead to very strong asymmetries in the...
Agarwal,G. S., Von Zanthier,J., Skornia,C., Walther,H.
The different behavior of first-order interferences and second-order correlations are investigated for the case of two coherently excited atoms. For intensity measurements this problem is in many...
Dark States and Interferences in Cascade Transitions of Ultra-Cold Atoms in a Cavity (2002)
We examine the competition among one- and two-photon processes in an ultra-cold, three-level atom undergoing cascade transitions as a result of its interaction with a bimodal cavity. We show...
Scheme to Measure Quantum Stokes Parameters and their Fluctuations and Correlations (2002)
Agarwal, G. S., Chaturvedi, S.
We propose a scheme to measure quantum Stokes parameters, their fluctuations and correlations. The proposal involves measurements of intensities and intensity- intensity correlations for suitably...
Strong-driving-assisted multipartite entanglement in cavity QED (2002)
Solano, E., Agarwal, G. S., Walther, H.
We propose a method of generating multipartite entanglement by considering the interaction of a system of N two-level atoms in a cavity of high quality factor with a strong classical driving field....
Heisenberg's Uncertainty Relations and Quantum Optics (2002)
We present a brief review of the impact of the Heisenberg uncertainty relations on quantum optics. In particular we demonstrate how almost all coherent and nonclassical states of quantum optics can...
Coherent medium as a polarization splitter of pulses (2002)
Agarwal, G. S., Dasgupta, Shubhrangshu
We show how one can use the anisotropic properties of a coherent medium to separate temporally the two polarization components of a linearly polarized pulse. This is achieved by applying a control...
Agarwal, G. S., Von Zanthier, J., Skornia, C., Walther, H.
The different behavior of first-order interferences and second-order correlations are investigated for the case of two coherently excited atoms. For intensity measurements this problem is in many...
Agarwal, G. S., Puri, R. R., Singh, R. P.
We point out the relation between the work of Zheng and ours, APS [G.S. Agarwal, R.R. Puri, and R.P. Singh, Phys. Rev. A 56, 2249 (2001)] and show the important connection between the atomic cat...
Stoppage of Light Made Flexible by an Additional Control Field (2001)
Agarwal, G. S., Dey, Tarak Nath
We show how the application of a coupling field connecting the two lower metastable states of a Lambda system facilitates stoppage of light in a coheren tly driven Doppler broadened atomic medium via...
Tripartite Entanglement in a Bose Condensate by Stimulated Bragg Scattering (2001)
We show that it is possible to entangle three different many-particle states by Bragg spectroscopy with nonclassical light in a Bose condensate of weakly interacting atomic gases. Among these three...
Agarwal, G. S., Von Zanthier, J., Skornia, C., Walther, H.
The different behaviour of first order interferences and second order correlations are investigated for the case of two coherently excited atoms. For intensity measurements this problem is equivalent...
Coherent Control of Magneto-optical Rotation in Inhomogeneously Broadened Medium (2001)
Patnaik, Anil K., Agarwal, G. S.
We extend our earlier investigations [Opt. Commun. {\bf 179}, 97 (2000)] on the enhancement of magneto-optical rotation (MOR) to include inhomogeneous broadening. We introduce a control field that...
A Knob for Changing Light Propagation from Subluminal to Superluminal (2001)
Agarwal, G. S., Dey, Tarak Nath, Menon, Sunish
We show how the application of a coupling field connecting the two lower metastable states of a lambda-system can produce a variety of new results on the propagation of a weak electromagnetic pulse....
Monitoring the Dipole-Dipole Interaction via Quantum Jumps of Individual Atoms (2001)
Skornia, C., Von Zanthier, J., Agarwal, G. S., Werner, E., Walther, H.
The emission characteristics in the fluorescence of two laser-driven dipole-dipole-interacting three level atoms is investigated. When the light from both atoms is detected separately a correlation...
Nonclassical Interference Effects In The Radiation From Coherently Driven Uncorrelated Atoms (2001)
Skornia, C., Von Zanthier, J., Agarwal, G. S., Werner, E., Walther, H.
We demonstrate the existence of new nonclassical correlations in the radiation of two atoms, which are coherently driven by a continuous laser source. The photon-photon-correlations of the...
Tunneling and Traversal of Ultra-cold Atoms through Vacuum Induced Potentials (2001)
We examine the passage of ultra-cold two-level atoms through the potential produced by the vacuum of the cavity field. The peak of the transmitted wave packet generally occurs at the instant given by...
Quantum State Tomography of Complex Multimode Fields using Array Detectors (2001)
We demonstrate that it is possible to use the balanced homodyning with array detectors to measure the quantum state of correlated two-mode signal field. We show the applicability of the method to...
Inhibition of Decoherence due to Decay in a Continuum (2001)
Agarwal, G. S., Scully, M. O., Walther, H.
We propose a scheme for slowing down decay into a continuum. We make use of a sequence of ultrashort $2\pi$-pulses applied on an auxiliary transition of the system so that there is a destructive...
Giant Radiative Interactions Among Distant Atoms (2000)
Agarwal, G. S., Gupta, S. Dutta
We examine the feasibility of enhancing the fundamental radiative interactions between distant atoms. We present general arguments for producing enhancement. In particular, we show how giant...
Vacuum Induced Coherences in Radiatively Coupled Multilevel Systems (2000)
Agarwal, G. S., Patnaik, Anil K.
We show that radiative coupling between two multilevel atoms having near-degenerate states can produce new interference effects in spontaneous emission. We explicitly demonstrate this possibility by...
Improving the Fidelity of Quantum Cloning by Fast Cycling away the Unwanted Transition (2000)
Dasgupta, Shubhrangshu, Agarwal, G. S.
The fidelity of quantum cloning is very often limited by the accompanying unwanted transitions. We show how the fidelity can be improved by using a coherent field to cycle away the unwanted...
Quantum Coherence in a Single Ion due to strong Excitation of a metastable Transition (2000)
Von Zanthier, J., Skornia, C., Agarwal, G. S., Walther, H.
We consider pump-probe spectroscopy of a single ion with a highly metastable (probe) clock transition which is monitored by using the quantum jump technique. For a weak clock laser we obtain the well...