The Experts below are selected from a list of 3051 Experts worldwide ranked by ideXlab platform
Suhail M Zubairy - One of the best experts on this subject based on the ideXlab platform.
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gaussian state entanglement in a Quantum Beat laser
2011Co-Authors: Rabia Tahira, Manzoor Ikram, Hyunchul Nha, Suhail M ZubairyAbstract:Recently Quantum Beat lasers have been considered as a source of entangled radiation [S. Qamar, F. Ghafoor, M. Hillery, and M. S. Zubairy, Phys. Rev. A 77, 062308 (2008)]. We investigate and quantify the entanglement of this system when the initial cavity modes are prepared in a Gaussian two-mode state, one being a nonclassical state and the other a thermal state. It is investigated how the output entanglement varies with the nonclassicality of the input Gaussian state, thermal noise, and the strength of the driving field.
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Quantum Beat laser as a source of entangled radiation
2008Co-Authors: Shahid Qamar, Fazal Ghafoor, Suhail M Zubairy, Mark HilleryAbstract:We consider a Quantum Beat laser [Scully and Zubairy, Phys. Rev. A 35 752 (1987)] as a source of entangled radiation. The system essentially consists of three-level atoms inside a doubly resonant cavity such that coherence is introduced by driving the upper two levels with a strong classical field of Rabi frequency $\ensuremath{\Omega}$. We study the dynamics of this system for different values of Rabi frequencies in the presence of cavity losses. It is shown that entanglement can be generated in this system for different initial states of the field in the two modes.
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entanglement generation in a two mode Quantum Beat laser
2007Co-Authors: Manzoor Ikram, Suhail M ZubairyAbstract:We analyze the Quantum correlations between side modes of a Quantum Beat laser when a two-level atomic medium is driven strongly by a classical field. The squeezing and the entanglement generation of the cavity radiation are investigated. It turns out that there is neither squeezing nor entanglement when the strong driving field is resonant with the atomic transition but the generated light exhibits both two-mode squeezing and entanglement when the driving field is tuned away from the atomic transition.
Robert J Huber - One of the best experts on this subject based on the ideXlab platform.
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Quantum Beat spectroscopy in chemistry
2000Co-Authors: Robert T Carter, Robert J HuberAbstract:Quantum Beat spectroscopy is a Doppler-free time domain method based on the creation of molecular coherences with a laser pulse and the measurement of their subsequent time evolution. Fourier transformation of the time evolution allows a spectrum in the frequency domain with lifetime- limited resolution to be recovered. This article gives an account of the technique applied in high resolution mode which allows the study of isolated molecules, radicals and complexes in extensive detail and with great accuracy.
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Quantum Beat study of the nuclear hyperfine structure of od and ar od in their a 2σ electronic states
1996Co-Authors: Robert T Carter, H Bitto, Ian M Povey, Robert J HuberAbstract:The nuclear hyperfine structure of OD and Ar⋅OD in their A 2Σ+ electronic states has been studied by Quantum Beat spectroscopy. The very cold transient species were produced in a supersonic expansion using a pulsed discharge nozzle. Coherent excitation of hyperfine (hf) states, arising from one fine structure (OD) or rotational (Ar⋅OD) level, created Quantum Beats on the fluorescence decay. The Beat frequencies, which correspond to energy separations between hf levels, could be measured to ±75 kHz. The splitting of the hf levels into their Zeeman components was investigated in a weak magnetic field. A fit of the zero field and Zeeman data yielded the relevant constants for the nuclear magnetic and electric quadrupole hyperfine interactions as well as the pertinent g‐factors in each species. In the case of OD, the hf parameters agree well with those reported previously but are more accurately defined. For Ar⋅OD the previously unknown hyperfine and spin‐rotation parameters of the A 2Σ+ state were determined...
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Quantum Beat spectroscopy of jet cooled transient radicals generated by a pulsed electrical discharge
1996Co-Authors: Ian M Povey, Robert T Carter, H Bitto, Robert J HuberAbstract:Abstract Using a pulsed electrical discharge nozzle, we have extended Quantum Beat spectroscopy to radicals in a molecular beam. To demonstrate the method, we studied three prototypical systems: the diatomic radical OD, the radical van der Waals complex Ar·OD and the polyatomic vinoxy radical (CH 2 CHO). In all three cases hyperfine Quantum Beats were observed and identified on the fluorescence decays from excited electronic states with or without an external magnetic field. The application of this method to other radical systems is discussed.
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nuclear quadrupole Quantum Beat spectroscopy in the electronic ground state of a polyatomic molecule by an ir uv double resonance method
1995Co-Authors: Robert T Carter, Th Walther, Herbert Bitto, Robert J HuberAbstract:The feasibility of determining nuclear quadrupole hyperfine splittings in the ground electronic state of a polyatomic molecule using a double resonance Quantum Beat method has been demonstrated. Pyrimidine molecules were coherently excited into single rotational states of the S0 201 (13a1) vibrational level. The resulting hyperfine level coherences were then probed, after a variable time delay, by excitation to the S1 O0 level with subsequent fluorescence detection. Analysis showed that the quadrupole structure in the 201 (13a1) level is similar to that previously measured in the vibrational ground state. Applications of this method and possible experimental extensions are discussed.
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spin uncoupling in 3a2 cs2 studied by high resolution zeeman and hyperfine Quantum Beat spectroscopy
1992Co-Authors: D T Cramb, H Bitto, Robert J HuberAbstract:The magnetic properties of the evsB2 spin component of the 3A2 state in the molecule CS2 have been investigated with a resolution of ∼100 kHz by Quantum Beat spectroscopy in a supersonic jet. Zeeman‐level tuning in 12CS2 and 13CS2, providing Lande g factors, and measurements of the 13CS2 nuclear hyperfine structure were carried out, particularly to investigate their J dependence. Based on these results, it is proposed that both the magnetic moment and the hyperfine splitting are dominated by spin‐uncoupling interactions, described in the rotational Hamiltonian by B(J−S).2 In addition, the g factors and rotational state lifetimes were used to provide spectroscopic assignments and to elucidate details of the state mixing.
C V Shank - One of the best experts on this subject based on the ideXlab platform.
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investigation of femtosecond electronic dephasing in cdse nanocrystals using Quantum Beat suppressed photon echoes
2005Co-Authors: R W Schoenlein, Daniel M Mittleman, J J Shiang, A P Alivisatos, C V ShankAbstract:We report the first direct measurements of femtosecond electronic dephasing in CdSe nanocrystals using three-pulse photon echoes and a novel mode-suppression technique. We are able to separate the dynamics of the coherently excited LO phonons from the underlying electron-hole dephasing by suppressing the Quantum Beats. The homogeneous linewidth of these materials at 15 K results from electronic dephasing in -85 fs, approximately half of which is due to acoustic phonon modes. Contributions from acoustic phonons dominate the homogeneous linewidth at room temperature.
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investigation of femtosecond electronic dephasing in cdse nanocrystals using Quantum Beat suppressed photon echoes
1993Co-Authors: R W Schoenlein, Daniel M Mittleman, J J Shiang, A P Alivisatos, C V ShankAbstract:We report the first direct measurements of femtosecond electronic dephasing in CdSe nanocrystals using three-pulse photon echoes and a novel mode-suppression technique. We are able to separate the dynamics of the coherently excited LO phonons from the underlying electron-hole dephasing by suppressing the Quantum Beats. The homogeneous linewidth of these materials at 15 K results from electronic dephasing in \ensuremath{\sim}85 fs, approximately half of which is due to acoustic phonon modes. Contributions from acoustic phonons dominate the homogeneous linewidth at room temperature.
John S. Muenter - One of the best experts on this subject based on the ideXlab platform.
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dipole moment of water in highly vibrationally excited states analysis of photofragment Quantum Beat spectroscopy measurements using a local mode hamiltonian
2009Co-Authors: Patrice Theule, John S. Muenter, A CallegariAbstract:We present here the analysis of experimental Stark effect measurements made using photofragment Quantum Beat spectroscopy on the 14,0->, 15,0->, 18,0+> and 14,0-> 12 > vibrational states of H2O [Callegari, A.; et al. Science 2002, 297, 993.]. To link the measured Stark coefficients with the dipole surface, we analyze our results using a coupled anharmonic oscillator model, which takes into account the local-mode nature of higly excited OH stretching vibrations in water, and the tunneling between the two equivalent bonds. The large inertial frame tilt associated with the local-mode bond stretching results in a complex interaction between rotational-, vibrational-, and tunneling-motion, all of which become deeply entangled in the Stark coefficients. A perturbational approach makes it possible to analyze the problem at increasingly higher levels of approximation and to disentangle the different contributions, according to the different time scales involved. This simple model reproduces most experimental values to within a few percent, even for these highly vibrationally excited levels, and gives valuable insight into the complex rotational and vibrational motions that link the dipole moment surface with the Stark coefficients.
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dipole moments of hdo in highly excited vibrational states measured by stark induced photofragment Quantum Beat spectroscopy
2005Co-Authors: Patrice Theule, A Callegari, Thomas R Rizzo, John S. MuenterAbstract:We report here a measurement of electric dipole moments in highly vibrationally excited HDO molecules. We use photofragment yield detected Quantum Beat spectroscopy to determine electric field induced splittings of the J=1 rotational levels of HDO excited with 4, 5, and 8 quanta of vibration in the OH stretching mode. The splittings allow us to deduce μa and μb, the projections of dipole moment onto the molecular rotation inertial axes. We compare the measured HDO dipole moment components with the results of quantitative calculations based on Morse oscillator wave functions and an ab initio dipole moment surface. The vibrational dependence of the dipole moment components reflect both structural and electronic changes in HDO upon vibrational excitation; principally the vibrational dependence of the O–H bond length and bond angle, and the resulting change in orientation of the principal inertial coordinate system. The dipole moment data also provide a sensitive test of theoretical dipole moment and potentia...
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dipole moments of hdo in highly excited vibrational states measured by stark induced photofragment Quantum Beat spectroscopy
2005Co-Authors: Patrice Theule, A Callegari, Thomas R Rizzo, John S. MuenterAbstract:We report here a measurement of electric dipole moments in highly vibrationally excited HDO molecules. We use photofragment yield detected Quantum Beat spectroscopy to determine electric field induced splittings of the J=1 rotational levels of HDO excited with 4, 5, and 8 quanta of vibration in the OH stretching mode. The splittings allow us to deduce mu(a) and mu(b), the projections of dipole moment onto the molecular rotation inertial axes. We compare the measured HDO dipole moment components with the results of quantitative calculations based on Morse oscillator wave functions and an ab initio dipole moment surface. The vibrational dependence of the dipole moment components reflect both structural and electronic changes in HDO upon vibrational excitation; principally the vibrational dependence of the O-H bond length and bond angle, and the resulting change in orientation of the principal inertial coordinate system. The dipole moment data also provide a sensitive test of theoretical dipole moment and potential energy surfaces, particularly for molecular configurations far from equilibrium.
Patrice Theule - One of the best experts on this subject based on the ideXlab platform.
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dipole moment of water in highly vibrationally excited states analysis of photofragment Quantum Beat spectroscopy measurements using a local mode hamiltonian
2009Co-Authors: Patrice Theule, John S. Muenter, A CallegariAbstract:We present here the analysis of experimental Stark effect measurements made using photofragment Quantum Beat spectroscopy on the 14,0->, 15,0->, 18,0+> and 14,0-> 12 > vibrational states of H2O [Callegari, A.; et al. Science 2002, 297, 993.]. To link the measured Stark coefficients with the dipole surface, we analyze our results using a coupled anharmonic oscillator model, which takes into account the local-mode nature of higly excited OH stretching vibrations in water, and the tunneling between the two equivalent bonds. The large inertial frame tilt associated with the local-mode bond stretching results in a complex interaction between rotational-, vibrational-, and tunneling-motion, all of which become deeply entangled in the Stark coefficients. A perturbational approach makes it possible to analyze the problem at increasingly higher levels of approximation and to disentangle the different contributions, according to the different time scales involved. This simple model reproduces most experimental values to within a few percent, even for these highly vibrationally excited levels, and gives valuable insight into the complex rotational and vibrational motions that link the dipole moment surface with the Stark coefficients.
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dipole moments of hdo in highly excited vibrational states measured by stark induced photofragment Quantum Beat spectroscopy
2005Co-Authors: Patrice Theule, A Callegari, Thomas R Rizzo, John S. MuenterAbstract:We report here a measurement of electric dipole moments in highly vibrationally excited HDO molecules. We use photofragment yield detected Quantum Beat spectroscopy to determine electric field induced splittings of the J=1 rotational levels of HDO excited with 4, 5, and 8 quanta of vibration in the OH stretching mode. The splittings allow us to deduce μa and μb, the projections of dipole moment onto the molecular rotation inertial axes. We compare the measured HDO dipole moment components with the results of quantitative calculations based on Morse oscillator wave functions and an ab initio dipole moment surface. The vibrational dependence of the dipole moment components reflect both structural and electronic changes in HDO upon vibrational excitation; principally the vibrational dependence of the O–H bond length and bond angle, and the resulting change in orientation of the principal inertial coordinate system. The dipole moment data also provide a sensitive test of theoretical dipole moment and potentia...
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dipole moments of hdo in highly excited vibrational states measured by stark induced photofragment Quantum Beat spectroscopy
2005Co-Authors: Patrice Theule, A Callegari, Thomas R Rizzo, John S. MuenterAbstract:We report here a measurement of electric dipole moments in highly vibrationally excited HDO molecules. We use photofragment yield detected Quantum Beat spectroscopy to determine electric field induced splittings of the J=1 rotational levels of HDO excited with 4, 5, and 8 quanta of vibration in the OH stretching mode. The splittings allow us to deduce mu(a) and mu(b), the projections of dipole moment onto the molecular rotation inertial axes. We compare the measured HDO dipole moment components with the results of quantitative calculations based on Morse oscillator wave functions and an ab initio dipole moment surface. The vibrational dependence of the dipole moment components reflect both structural and electronic changes in HDO upon vibrational excitation; principally the vibrational dependence of the O-H bond length and bond angle, and the resulting change in orientation of the principal inertial coordinate system. The dipole moment data also provide a sensitive test of theoretical dipole moment and potential energy surfaces, particularly for molecular configurations far from equilibrium.
