Skip to main content

S. Guérin

Followers

10

Following

4

Co-authors

3

Public Views

Sofia University "St. Kliment Ohridski"

Dr Jason J Braithwaite

Lancaster University

shant shahbazian

Shahid Beheshti University

Queen Mary, University of London

Rajapandiyan Panneerselvam

SRM UNIVERSITY

Indian Institute of Science

Giovanni Cantele

Consiglio Nazionale delle Ricerche (CNR)

University of Alabama at Birmingham

University of Dr moulay taher

Mustafa Odabasoglu

Pamukkale University

Interests

Uploads

Papers by S. Guérin

Multiphoton processes in lambda three-level systems

AIP Conference Proceedings, 2000

We study population transfer and multiphoton processes occurring in lambda three-level systems dr... more We study population transfer and multiphoton processes occurring in lambda three-level systems driven by two pulse-shaped laser fields. We choose parameters that are known from numerical solutions of the the semiclassical time dependent Schrödinger equation to induce complete population transfer. We construct in the frame of the adiabatic Floquet theory the associated dressed Schrödinger equation and show that it reveals additional information not contained in the semiclassical Schrödinger equation: the population transfer is accompanied by multiphoton absorption from and emission into the laser fields, where time dependence can be explicitly calculated in the Floquet representation. .

Enhanced alignment and orientation of polar molecules by vibrational resonant adiabatic passage

The Journal of Chemical Physics, 2007

The authors show that polar molecules can be adiabatically aligned and oriented by laser pulses m... more The authors show that polar molecules can be adiabatically aligned and oriented by laser pulses more efficiently when the laser frequencies are vibrationally resonant. The aligned molecules are found in a superposition of vibrational pendular states, each associated with the alignment of the rotor in one vibrational state. The authors construct the dressed potential associated with this mechanism. Values of detunings and field amplitudes are given to optimize the degree of alignment and orientation for the CO molecule.

Quantum state engineering in ion-traps via adiabatic passage

The European Physical Journal D, 2012

ABSTRACT We propose two relatively robust schemes to generate entangled W states of three (or gen... more ABSTRACT We propose two relatively robust schemes to generate entangled W states of three (or generally N) ions in ion trap systems by using adiabatic passage technique and appropriately designed ion-field couplings in a single step. In the first scheme, we apply the N-pod fractional stimulated Raman adiabatic passage (F-STIRAP) technique to generate W state of N ions using two Gaussian laser pulses. We also show that the W state of N − 1 ions can be created via a simple N-pod standard STIRAP by two laser pulses. In the second scheme, we generate the entangled state of N ions via π-pulse technique by a single laser pulse. We also study the population transfer of the system by numerical solutions of the master equation, considering the effect of decoherence channels due to laser intensity fluctuations and dissipation in the phonon modes.

Laser control of the radiationless decay in pyrazine using the dynamic Stark effect

The Journal of chemical physics, Jan 21, 2014

The laser control of the radiationless decay between the B(3u)(nπ*) and B(2u)(ππ*) states of pyra... more The laser control of the radiationless decay between the B(3u)(nπ*) and B(2u)(ππ*) states of pyrazine using the dynamic Stark effect has been investigated. A vibronic coupling model Hamiltonian in diabatic representation, including potential energy, transition dipole, and static polarizability surfaces as a function of the four most important vibrational modes of the molecule has been parametrized using multi-reference electronic structure calculations. The interaction of the molecule with a strong non-resonant laser pulse has been analyzed in terms of dressed potential energy surfaces. Because of the large polarizability difference between the vibronically coupled B(3u)(nπ*) and B(2u)(ππ*) states, the Stark effect induced by the non-resonant laser pulse shifts the conical intersection away from the Franck-Condon region. We have shown, by solving the time-dependent Schrödinger equation for the molecule interacting with a relatively weak pump pulse driving the electronic excitation f...

Influence of Unequal Oscillator Strengths on Stimulated Raman Adiabatic Passage Through Bright State

International Journal of Modern Physics: Conference Series, 2012

In the present work an analytical and numerical analysis of the b -STIRAP process in a medium wit... more

La molécule d'éthylène soumise à des impulsions laser femtosecondes : spectroscopie rotationnelle et alignement

Talk given by B. Lavore

Chaotic spin-spin entanglement on a recursive lattice

Physical review. E, Statistical, nonlinear, and soft matter physics, 2015

We propose an exactly solvable multisite interaction spin-1/2 Ising-Heisenberg model on a triangu... more We propose an exactly solvable multisite interaction spin-1/2 Ising-Heisenberg model on a triangulated Husimi lattice for the rigorous studies of chaotic entanglement. By making use of the generalized star-triangle transformation, we map the initial model onto an effective Ising one on a Husimi lattice, which we solve then exactly by applying the recursive method. Expressing the entanglement of the Heisenberg spins, that we quantify by means of the concurrence, in terms of the magnetic quantities of the system, we demonstrate its bifurcation and chaotic behavior. Furthermore, we show that the underlying chaos may slightly enhance the amount of the entanglement and present on the phase diagram the transition lines from the uniform to periodic and from the periodic to chaotic regimes.

Adiabatic Evolution Through Infinitely many Eigenvalue Crossings

Equadiff 99, 2000

Comparing the electronic relaxation dynamics of aniline and d7-aniline following excitation at 272–238 nm

Physical Chemistry Chemical Physics, 2015

Femtosecond studies of electronic relaxation in aniline reveal evidence for a 3-state conical int... more

Coherent destruction of tunneling in a six-dimensional model of NHD2: a computational study using the multi-configuration time-dependent Hartree method

The Journal of chemical physics, Jan 28, 2014

We investigate the phenomenon of coherent destruction of tunneling in a six-dimensional model of ... more We investigate the phenomenon of coherent destruction of tunneling in a six-dimensional model of the NHD2 molecule. Two regimes are considered for the frequency of the laser field. A non-resonant regime where the frequency of the laser field is high with respect to the ground vibrational state tunneling splitting but smaller than the transition frequencies between the ground and excited vibrational states; and a quasi-resonant regime where the frequency of the laser field is close to the transition frequency between the ground and first excited vibrational states. In each case, we study the laser driven dynamics in the framework of the Floquet formalism and derive simple analytical formulas that explain the shape of the quasienergy curves associated with the two tunneling components of the ground vibrational state. This analysis allows us to obtain the parameters (frequency and amplitude) of the laser field that lead to the coherent destruction of tunneling. The multi-configuration ...

Uniform analytic description of dephasing effects in two-state transitions

Physical Review A - Atomic, Molecular, and Optical Physics, 2007

Understanding of the electronic structure and photoexcited state dynamics at well-prepared layere... more Understanding of the electronic structure and photoexcited state dynamics at well-prepared layered functional materials on substrates is essentially important in order to precisely design and control the future electronic or optical nanodevices. I have been so far engaged in this research field experimentally from the view point of molecular science, where the electronic states and dynamics at nanoscale functional films fabricated with organic molecules and/or nanocluster superatoms are investigated by probing photoelectrons, combining with a femtosecond light source and with a nanocluster deposition system. In this account, firstly, I show the electronic structures and photoexcited state dynamics at two-dimensional (2D) molecular monolayer systems of alkanethiolate self-assembled monolayers by two-photon photoemission spectroscopy which clarifies novel ultrafast phenomena characteristic to the 2D assembly of the functional molecules. Secondly, I present the visualization of local photoexcited states in the organic films by changing the probe system into two-photon photoelectron emission microscopy. Finally, the electronic states and chemical properties of nanocluster superatoms as a new class of functional nanomaterials are explained, which are non-destructively landed onto the substrates.

<title>Superluminal pulse propagation in a non-linear Λ-type atomic medium</title>

Photonics and Micro- and Nano-structured Materials 2011, 2011

ABSTRACT Propagation of two optical pulses in a non-linear Λ-type atomic medium is considered. Th... more

High-Fidelity Adiabatic Passage by Composite Sequences of Chirped Pulses

Physical Review Letters, 2011

We present a method for optimization of the technique of adiabatic passage between two quantum st... more We present a method for optimization of the technique of adiabatic passage between two quantum states by composite sequences of frequency-chirped pulses with specific relative phases: composite adiabatic passage (CAP). By choosing the composite phases appropriately the nonadiabatic losses can be canceled to any desired order with sufficiently long sequences, regardless of the nonadiabatic coupling. The values of the composite phases are universal for they do not depend on the pulse shapes and the chirp. The accuracy of the CAP technique and its robustness against parameter variations make CAP suitable for high-fidelity quantum information processing.

Fast SWAP gate by adiabatic passage

Physical Review A, 2005

We present a process for the construction of a SWAP gate which does not require a composition of ... more We present a process for the construction of a SWAP gate which does not require a composition of elementary gates from a universal set. We propose to employ direct techniques adapted to the preparation of this specific gate. The mechanism, based on adiabatic passage, constitutes a decoherence-free method in the sense that spontaneous emission and cavity damping are avoided.

Ultimate field-free molecular alignment by combined adiabatic-impulsive field design

Physical Review A, 2008

We show that a laser pulse designed as an adiabatic ramp followed by a kick allows one to reach a... more We show that a laser pulse designed as an adiabatic ramp followed by a kick allows one to reach a perfect postpulse molecular alignment, free of saturation. The mechanism is based on an optimized distribution of the energy between a weakly efficient but non saturating adiabatic ramp and an efficient but saturating impulsive field. Unprecedent degrees of alignment are predicted using state-of-the-art pulse shaping techniques and non-destructive field intensities. The scheme can be extended to reach high degrees of orientation of polar molecules using designed half-cycle pulses.

Topology of adiabatic passage

Physical Review A, 2002

We examine the topology of eigenenergy surfaces characterizing the population transfer processes ... more We examine the topology of eigenenergy surfaces characterizing the population transfer processes based on adiabatic passage. We show that this topology is the essential feature for the analysis of the population transfers and the prediction of its final result. We reinterpret diverse known processes, such as stimulated Raman adiabatic passage (STIRAP), frequency-chirped adiabatic passage and Stark-chirped rapid adiabatic passage (SCRAP). Moreover, using this picture, we display new related possibilities of transfer. In particular, we show that we can selectively control the level which will be populated in STIRAP process in Λ or V systems by the choice of the peak amplitudes or the pulse sequence.

Field-free molecular alignment induced by elliptically polarized laser pulses: Noninvasive three-dimensional characterization

Physical Review A, 2007

An investigation of field-free molecular alignment produced by elliptically polarized laser pulse... more An investigation of field-free molecular alignment produced by elliptically polarized laser pulses is reported. Experiments are conducted in CO2 at room temperature. A non invasive all-optical technique, based on the cross defocusing of a probe pulse, is used to measure the alignment along two orthogonal directions that is sufficient to provide a 3 dimensional characterization. The fieldfree molecular alignment produced by a laser of elliptical polarization is in good agreement in terms of amplitude and shape with theoretical predictions. It turns out to be almost equivalent to the superposition of the effects that one would obtain with two individual cross-polarized pulses. The investigation highlights notably the occurrence of field-free two-direction alignment alternation for a suitably chosen degree of ellipticity. The analogy between this specific ellipticity and the well known "magic angle" used in time resolved spectroscopy to prevent rotational contributions is discussed.

Field-free one-dimensional alignment of ethylene molecule

Physical Review A, 2006

We report an experimental study of non-adiabatic laser-induced molecular alignment of ethylene (C... more We report an experimental study of non-adiabatic laser-induced molecular alignment of ethylene (C2H4) using a linearly polarized short laser pulse of moderate intensity. The information about the confinement of the C=C bond axis along the direction of the applied electric field is obtained by measuring the depolarization of a second short pulse of weak intensity interacting with the molecules after they have been exposed to the first pulse. The experimental data are compared with the numerical simulation of the Schrödinger equation written for the non-resonant interaction of an asymmetric top rigid rotor with a linearly polarized electric field. The field-free alignment is described by analyzing the time evolution of the angular distribution of the molecular axes together with the expectation value of the relevant squared direction cosine matrix elements.

Optical gratings induced by field-free alignment of molecules

Physical Review A, 2007

We analyze the alignment of molecules generated by a pair of crossed ultra-short pump pulses of d... more We analyze the alignment of molecules generated by a pair of crossed ultra-short pump pulses of different polarizations by a technique based on the induced time-dependent gratings. Parallel polarizations yield an intensity grating, while perpendicular polarizations induce a polarization grating. We show that both configurations can be interpreted at moderate intensity as an alignment induced by a single polarized pump pulse. The advantage of the perpendicular polarizations is to give a signal of alignment that is free from the plasma contribution. Experiments on femtosecond transient gratings with aligned molecules were performed in CO2 at room temperature in a static cell and at 30 K in a molecular expansion jet.

Analog Grover search by adiabatic passage in a cavity-laser-atom system

Physical Review A, 2008

A physical implementation of the adiabatic Grover search is theoretically investigated in a syste... more A physical implementation of the adiabatic Grover search is theoretically investigated in a system of N identical three-level atoms trapped in a single mode cavity. Some of the atoms are marked through the presence of an energy gap between their two ground states. The search is controlled by two partially delayed lasers which allow a deterministic adiabatic transfer from an initially entangled state to the marked states. Pulse schemes are proposed to satisfy the Grover speedup either exactly or approximately, and the success rate of the search is calculated.

Multiphoton processes in lambda three-level systems

AIP Conference Proceedings, 2000

We study population transfer and multiphoton processes occurring in lambda three-level systems dr... more We study population transfer and multiphoton processes occurring in lambda three-level systems driven by two pulse-shaped laser fields. We choose parameters that are known from numerical solutions of the the semiclassical time dependent Schrödinger equation to induce complete population transfer. We construct in the frame of the adiabatic Floquet theory the associated dressed Schrödinger equation and show that it reveals additional information not contained in the semiclassical Schrödinger equation: the population transfer is accompanied by multiphoton absorption from and emission into the laser fields, where time dependence can be explicitly calculated in the Floquet representation. .

Enhanced alignment and orientation of polar molecules by vibrational resonant adiabatic passage

The Journal of Chemical Physics, 2007

The authors show that polar molecules can be adiabatically aligned and oriented by laser pulses m... more The authors show that polar molecules can be adiabatically aligned and oriented by laser pulses more efficiently when the laser frequencies are vibrationally resonant. The aligned molecules are found in a superposition of vibrational pendular states, each associated with the alignment of the rotor in one vibrational state. The authors construct the dressed potential associated with this mechanism. Values of detunings and field amplitudes are given to optimize the degree of alignment and orientation for the CO molecule.

Quantum state engineering in ion-traps via adiabatic passage

The European Physical Journal D, 2012

ABSTRACT We propose two relatively robust schemes to generate entangled W states of three (or gen... more ABSTRACT We propose two relatively robust schemes to generate entangled W states of three (or generally N) ions in ion trap systems by using adiabatic passage technique and appropriately designed ion-field couplings in a single step. In the first scheme, we apply the N-pod fractional stimulated Raman adiabatic passage (F-STIRAP) technique to generate W state of N ions using two Gaussian laser pulses. We also show that the W state of N − 1 ions can be created via a simple N-pod standard STIRAP by two laser pulses. In the second scheme, we generate the entangled state of N ions via π-pulse technique by a single laser pulse. We also study the population transfer of the system by numerical solutions of the master equation, considering the effect of decoherence channels due to laser intensity fluctuations and dissipation in the phonon modes.

Laser control of the radiationless decay in pyrazine using the dynamic Stark effect

The Journal of chemical physics, Jan 21, 2014

The laser control of the radiationless decay between the B(3u)(nπ*) and B(2u)(ππ*) states of pyra... more The laser control of the radiationless decay between the B(3u)(nπ*) and B(2u)(ππ*) states of pyrazine using the dynamic Stark effect has been investigated. A vibronic coupling model Hamiltonian in diabatic representation, including potential energy, transition dipole, and static polarizability surfaces as a function of the four most important vibrational modes of the molecule has been parametrized using multi-reference electronic structure calculations. The interaction of the molecule with a strong non-resonant laser pulse has been analyzed in terms of dressed potential energy surfaces. Because of the large polarizability difference between the vibronically coupled B(3u)(nπ*) and B(2u)(ππ*) states, the Stark effect induced by the non-resonant laser pulse shifts the conical intersection away from the Franck-Condon region. We have shown, by solving the time-dependent Schrödinger equation for the molecule interacting with a relatively weak pump pulse driving the electronic excitation f...

Influence of Unequal Oscillator Strengths on Stimulated Raman Adiabatic Passage Through Bright State

International Journal of Modern Physics: Conference Series, 2012

In the present work an analytical and numerical analysis of the b -STIRAP process in a medium wit... more

La molécule d'éthylène soumise à des impulsions laser femtosecondes : spectroscopie rotationnelle et alignement

Talk given by B. Lavore

Chaotic spin-spin entanglement on a recursive lattice

Physical review. E, Statistical, nonlinear, and soft matter physics, 2015

We propose an exactly solvable multisite interaction spin-1/2 Ising-Heisenberg model on a triangu... more We propose an exactly solvable multisite interaction spin-1/2 Ising-Heisenberg model on a triangulated Husimi lattice for the rigorous studies of chaotic entanglement. By making use of the generalized star-triangle transformation, we map the initial model onto an effective Ising one on a Husimi lattice, which we solve then exactly by applying the recursive method. Expressing the entanglement of the Heisenberg spins, that we quantify by means of the concurrence, in terms of the magnetic quantities of the system, we demonstrate its bifurcation and chaotic behavior. Furthermore, we show that the underlying chaos may slightly enhance the amount of the entanglement and present on the phase diagram the transition lines from the uniform to periodic and from the periodic to chaotic regimes.

Adiabatic Evolution Through Infinitely many Eigenvalue Crossings

Equadiff 99, 2000

Comparing the electronic relaxation dynamics of aniline and d7-aniline following excitation at 272–238 nm

Physical Chemistry Chemical Physics, 2015

Femtosecond studies of electronic relaxation in aniline reveal evidence for a 3-state conical int... more

Coherent destruction of tunneling in a six-dimensional model of NHD2: a computational study using the multi-configuration time-dependent Hartree method

The Journal of chemical physics, Jan 28, 2014

We investigate the phenomenon of coherent destruction of tunneling in a six-dimensional model of ... more We investigate the phenomenon of coherent destruction of tunneling in a six-dimensional model of the NHD2 molecule. Two regimes are considered for the frequency of the laser field. A non-resonant regime where the frequency of the laser field is high with respect to the ground vibrational state tunneling splitting but smaller than the transition frequencies between the ground and excited vibrational states; and a quasi-resonant regime where the frequency of the laser field is close to the transition frequency between the ground and first excited vibrational states. In each case, we study the laser driven dynamics in the framework of the Floquet formalism and derive simple analytical formulas that explain the shape of the quasienergy curves associated with the two tunneling components of the ground vibrational state. This analysis allows us to obtain the parameters (frequency and amplitude) of the laser field that lead to the coherent destruction of tunneling. The multi-configuration ...

Uniform analytic description of dephasing effects in two-state transitions

Physical Review A - Atomic, Molecular, and Optical Physics, 2007

Understanding of the electronic structure and photoexcited state dynamics at well-prepared layere... more Understanding of the electronic structure and photoexcited state dynamics at well-prepared layered functional materials on substrates is essentially important in order to precisely design and control the future electronic or optical nanodevices. I have been so far engaged in this research field experimentally from the view point of molecular science, where the electronic states and dynamics at nanoscale functional films fabricated with organic molecules and/or nanocluster superatoms are investigated by probing photoelectrons, combining with a femtosecond light source and with a nanocluster deposition system. In this account, firstly, I show the electronic structures and photoexcited state dynamics at two-dimensional (2D) molecular monolayer systems of alkanethiolate self-assembled monolayers by two-photon photoemission spectroscopy which clarifies novel ultrafast phenomena characteristic to the 2D assembly of the functional molecules. Secondly, I present the visualization of local photoexcited states in the organic films by changing the probe system into two-photon photoelectron emission microscopy. Finally, the electronic states and chemical properties of nanocluster superatoms as a new class of functional nanomaterials are explained, which are non-destructively landed onto the substrates.

<title>Superluminal pulse propagation in a non-linear Λ-type atomic medium</title>

Photonics and Micro- and Nano-structured Materials 2011, 2011

ABSTRACT Propagation of two optical pulses in a non-linear Λ-type atomic medium is considered. Th... more

High-Fidelity Adiabatic Passage by Composite Sequences of Chirped Pulses

Physical Review Letters, 2011

We present a method for optimization of the technique of adiabatic passage between two quantum st... more We present a method for optimization of the technique of adiabatic passage between two quantum states by composite sequences of frequency-chirped pulses with specific relative phases: composite adiabatic passage (CAP). By choosing the composite phases appropriately the nonadiabatic losses can be canceled to any desired order with sufficiently long sequences, regardless of the nonadiabatic coupling. The values of the composite phases are universal for they do not depend on the pulse shapes and the chirp. The accuracy of the CAP technique and its robustness against parameter variations make CAP suitable for high-fidelity quantum information processing.

Fast SWAP gate by adiabatic passage

Physical Review A, 2005

We present a process for the construction of a SWAP gate which does not require a composition of ... more We present a process for the construction of a SWAP gate which does not require a composition of elementary gates from a universal set. We propose to employ direct techniques adapted to the preparation of this specific gate. The mechanism, based on adiabatic passage, constitutes a decoherence-free method in the sense that spontaneous emission and cavity damping are avoided.

Ultimate field-free molecular alignment by combined adiabatic-impulsive field design

Physical Review A, 2008

We show that a laser pulse designed as an adiabatic ramp followed by a kick allows one to reach a... more We show that a laser pulse designed as an adiabatic ramp followed by a kick allows one to reach a perfect postpulse molecular alignment, free of saturation. The mechanism is based on an optimized distribution of the energy between a weakly efficient but non saturating adiabatic ramp and an efficient but saturating impulsive field. Unprecedent degrees of alignment are predicted using state-of-the-art pulse shaping techniques and non-destructive field intensities. The scheme can be extended to reach high degrees of orientation of polar molecules using designed half-cycle pulses.

Topology of adiabatic passage

Physical Review A, 2002

We examine the topology of eigenenergy surfaces characterizing the population transfer processes ... more We examine the topology of eigenenergy surfaces characterizing the population transfer processes based on adiabatic passage. We show that this topology is the essential feature for the analysis of the population transfers and the prediction of its final result. We reinterpret diverse known processes, such as stimulated Raman adiabatic passage (STIRAP), frequency-chirped adiabatic passage and Stark-chirped rapid adiabatic passage (SCRAP). Moreover, using this picture, we display new related possibilities of transfer. In particular, we show that we can selectively control the level which will be populated in STIRAP process in Λ or V systems by the choice of the peak amplitudes or the pulse sequence.

Field-free molecular alignment induced by elliptically polarized laser pulses: Noninvasive three-dimensional characterization

Physical Review A, 2007

An investigation of field-free molecular alignment produced by elliptically polarized laser pulse... more An investigation of field-free molecular alignment produced by elliptically polarized laser pulses is reported. Experiments are conducted in CO2 at room temperature. A non invasive all-optical technique, based on the cross defocusing of a probe pulse, is used to measure the alignment along two orthogonal directions that is sufficient to provide a 3 dimensional characterization. The fieldfree molecular alignment produced by a laser of elliptical polarization is in good agreement in terms of amplitude and shape with theoretical predictions. It turns out to be almost equivalent to the superposition of the effects that one would obtain with two individual cross-polarized pulses. The investigation highlights notably the occurrence of field-free two-direction alignment alternation for a suitably chosen degree of ellipticity. The analogy between this specific ellipticity and the well known "magic angle" used in time resolved spectroscopy to prevent rotational contributions is discussed.

Field-free one-dimensional alignment of ethylene molecule

Physical Review A, 2006

We report an experimental study of non-adiabatic laser-induced molecular alignment of ethylene (C... more We report an experimental study of non-adiabatic laser-induced molecular alignment of ethylene (C2H4) using a linearly polarized short laser pulse of moderate intensity. The information about the confinement of the C=C bond axis along the direction of the applied electric field is obtained by measuring the depolarization of a second short pulse of weak intensity interacting with the molecules after they have been exposed to the first pulse. The experimental data are compared with the numerical simulation of the Schrödinger equation written for the non-resonant interaction of an asymmetric top rigid rotor with a linearly polarized electric field. The field-free alignment is described by analyzing the time evolution of the angular distribution of the molecular axes together with the expectation value of the relevant squared direction cosine matrix elements.

Optical gratings induced by field-free alignment of molecules

Physical Review A, 2007

We analyze the alignment of molecules generated by a pair of crossed ultra-short pump pulses of d... more We analyze the alignment of molecules generated by a pair of crossed ultra-short pump pulses of different polarizations by a technique based on the induced time-dependent gratings. Parallel polarizations yield an intensity grating, while perpendicular polarizations induce a polarization grating. We show that both configurations can be interpreted at moderate intensity as an alignment induced by a single polarized pump pulse. The advantage of the perpendicular polarizations is to give a signal of alignment that is free from the plasma contribution. Experiments on femtosecond transient gratings with aligned molecules were performed in CO2 at room temperature in a static cell and at 30 K in a molecular expansion jet.

Analog Grover search by adiabatic passage in a cavity-laser-atom system

Physical Review A, 2008

A physical implementation of the adiabatic Grover search is theoretically investigated in a syste... more A physical implementation of the adiabatic Grover search is theoretically investigated in a system of N identical three-level atoms trapped in a single mode cavity. Some of the atoms are marked through the presence of an energy gap between their two ground states. The search is controlled by two partially delayed lasers which allow a deterministic adiabatic transfer from an initially entangled state to the marked states. Pulse schemes are proposed to satisfy the Grover speedup either exactly or approximately, and the success rate of the search is calculated.