Quantum Interference And Coherent Control In Dissipative Atomic Systems

This book brings together and discusses for the first time detailed analyses of the experiments with trapped ions, experiments on quantum beats, coherent population trapping, electromagnetically induced transparency (EIT), electromagnetically induced absorption, creation of dark-states polaritons, subluminal and superluminal light, realization of a Fock state, and interference experiments in atom optics on atom grating, momentum distribution, and atom tunneling. This book is unique in many respects and will fill a gap in the literature.

"Coherent Control of Four-Wave Mixing" discusses the frequency, temporal and spatial domain interplays of four-wave mixing (FWM) processes induced by atomic coherence in multi-level atomic systems. It covers topics in five major areas: the ultrafast FWM polarization beats due to interactions between multi-color laser beams and multi-level media; coexisting Raman-Rayleigh-Brillouin-enhanced polarization beats due to color-locking noisy field correlations; FWM processes with different kinds of dual-dressed schemes in ultra-thin, micrometer and long atomic cells; temporal and spatial interference between FWM and six-wave mixing (SWM) signals in multi-level electromagnetically induced transparency (EIT) media; spatial displacements and splitting of the probe and generated FWM beams, as well as the observations of gap soliton trains, vortex solitons, and stable multicomponent vector solitons in the FWM signals. The book is intended for scientists, researchers, advanced undergraduate and graduate students in Nonlinear Optics. Dr. Yanpeng Zhang is a professor and Zhiqiang Nie is a Ph. D. student at the Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi'an Jiaotong University, China. Dr. Min Xiao is a professor of physics at the University of Arkansas, Fayetteville, U.S.A.

The field of atomic, molecular, and optical (AMO) science underpins many technologies and continues to progress at an exciting pace for both scientific discoveries and technological innovations. AMO physics studies the fundamental building blocks of functioning matter to help advance the understanding of the universe. It is a foundational discipline within the physical sciences, relating to atoms and their constituents, to molecules, and to light at the quantum level. AMO physics combines fundamental research with practical application, coupling fundamental scientific discovery to rapidly evolving technological advances, innovation and commercialization. Due to the wide-reaching intellectual, societal, and economical impact of AMO, it is important to review recent advances and future opportunities in AMO physics. Manipulating Quantum Systems: An Assessment of Atomic, Molecular, and Optical Physics in the United States assesses opportunities in AMO science and technology over the coming decade. Key topics in this report include tools made of light; emerging phenomena from few- to many-body systems; the foundations of quantum information science and technologies; quantum dynamics in the time and frequency domains; precision and the nature of the universe, and the broader impact of AMO science.

Advanced research reference examining the closed and open quantum systems Control of Quantum Systems: Theory and Methods provides an insight into the modern approaches to control of quantum systems evolution, with a focus on both closed and open (dissipative) quantum systems. The topic is timely covering the newest research in the field, and presents and summarizes practical methods and addresses the more theoretical aspects of control, which are of high current interest, but which are not covered at this level in other text books. The quantum control theory and methods written in the book are the results of combination of macro-control theory and microscopic quantum system features. As the development of the nanotechnology progresses, the quantum control theory and methods proposed today are expected to be useful in real quantum systems within five years. The progress of the quantum control theory and methods will promote the progress and development of quantum information, quantum computing, and quantum communication. Equips readers with the potential theories and advanced methods to solve existing problems in quantum optics/information/computing, mesoscopic systems, spin systems, superconducting devices, nano-mechanical devices, precision metrology. Ideal for researchers, academics and engineers in quantum engineering, quantum computing, quantum information, quantum communication, quantum physics, and quantum chemistry, whose research interests are quantum systems control.

In memoriam. Herbert Walther, scientist extraordinaire / P. Meystre. Willis E. Lamb / P. Berman -- Nobel Laureate session. When is a quantum gas a quantum liquid? / E.A. Cornell. Cooperative emission of light quanta : a theory of coherent radiation damping / R.J. Glauber. Coherent control of ultracold matter : fractional quantum Hall physics and large-area atom interferometry / S. Chu -- Precision measurements. More accurate measurement of the electron magnetic moment and the fine structure constant / G. Gabrielse. Determination of the fine structure constant with atom interferometry and Bloch oscillations / F. Biraben. Precise measurements of s-wave scattering phase shifts with a juggling atomic clock / K. Gibble. Quantum control of spins and photons at nanoscales / M.D. Lukin -- Quantum information and quantum optics. Atomic ensemble quantum memories / A. Kuzmich. Quantum non-demolition photon counting and time-resolved reconstruction of non-classical field states in a cavity / S. Haroche. Spin squeezing on an atomic-clock transition / V. Vuletić. Quantum micro-mechanics with ultracold atoms / D. Stamper-Kurn. Improved "position squared" readout using degenerate cavity modes / J.G.E. Harris -- Quantum degenerate systems. Tunable interactions in a Bose-Einstein condensate of Lithium : photoassociation and disorder-induced localization / R.G. Hulet. A purely dipolar quantum gas / T. Pfau. Bose-Einstein condensation of exciton-polaritons / Y. Yamamoto. Anderson localization of matter waves / P. Bouyer. Anderson localization of a non-interacting Bose-Einstein condensate / M. Inguscio. Fermi gases with tunable interactions / J.E. Thomas. Photoemission spectroscopy for ultracold atoms / D.S. Jin. Universality in strongly interacting Fermi gases / P.D. Drummond. Mapping the phase diagram of a two-component Fermi gas with strong interactions / Y. Shin. Exploring universality of few-body physics based on ultracold atoms near Feshbach resonances / C. Chin -- Optical lattices and cold molecules. Atom interferometry with a weakly interacting Bose-Einstein condensate / G. Modugno. An optical plaquette : minimum expressions of topological matter / B. Paredes. Strongly correlated bosons and fermions in optical lattices / I. Bloch. Laser cooling of molecules / P. Pillet. A dissipative Tonks-Girardeau gas of molecules / S. Dürr. Spectroscopy of ultracold KRb molecules / W.C. Stwalley. Cold molecular ions : single molecule studies / M. Drewsen -- Ultrafast phenomena. The frontiers of attosecond physics / L.F. DiMauro. Strong-field control of X-ray processes / L. Young

Quantum mechanics, arguably one of the greatest achievements of modern physics, has not only fundamentally changed our understanding of nature but is also taking an ever increasing role in engineering. Today, the control of quantum systems has already had a far-reaching impact on time and frequency metrology. By gaining further control over a large variety of different quantum systems, many potential applications are emerging. Those applications range from the development of quantum sensors and new quantum metrological approaches to the realization of quantum information processors and quantum networks. Unfortunately most quantum systems are very fragile objects that require tremendous experimental effort to avoid dephasing. Being able to control the interaction between a quantum system with its local environment embodies therefore an important aspect for application and hence is at the focus of this thesis.

Quantum interference and coherence lead to many interesting phenomenon and applications in quantum optics. In this dissertation, we study the quantum coherent properties in the following systems and aspects. We first investigate the optical bistability in a combined cavity-cold atoms system. In such a system the atom-photon interaction provides an optical lattice to the atoms and affects the mechanical motion of the atoms while atoms induce a position dependent phase shift on the cavity field. This highly nonlinearity induces optical bistability of intra-cavity photon number with respect to the pumping light added along the cavity axis. We show that the presence of this bistability can be controlled by a second pumping field added perpendicular to the cavity axis. It is also found that the critical input intensity of switching from one branch of bistability to the other depends on the the way of the field being added. This behavior is similar to the anomalous switching of the dispersive optical bistability of atomic media in the cavity. We also study the effect of counter-rotating terms in the control of spontaneous emission. We make use of a unitary transformation method and investigate the effect of dynamic energy shifts on the spontaneous emission modification via quantum interference in a four-level atomic system. We show that the counter-rotating terms, which are normally neglected in the usual investigation of atomic systems, do produce a significant influence on the evolution of the atomic amplitudes and the emission spectrum. This effect of counter-rotating terms can be observed in the time scale of the decay rate even when the dipole moments of the two upper levels are orthogonal to each other. The effect of counter-rotating terms on the spontaneous emission in a 3-D anisotropic photonic crystal is also discussed. It is shown that the behavior of the emission is similar to the case making rotating wave approximation, i.e., the localized and propagating fields are also separated by two characteristic atomic transition frequencies. However, the two characteristic frequencies are shifted due to the full Lamb shift which is obtained with counter-rotating terms being included in the Hamiltonian. We also utilize the unitary transformation method to show how the Lamb shift in a multi-level atom can be controlled by a driving field. Finally, we propose a subwavelength atom localization scheme for an atom located in a standing-wave field. The strategy is based on the observation that the photon statistics of resonance fluorescence depends on the position-dependent Rabi frequency. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/151685

Control is important for transferring theoretical scientific knowledge into practical technology for applications in numerous fields. This is why coherent control study is significant on every timescale to have a complete understanding of dynamic processes that occur on the electron, atomic and molecular levels. As a result, numerous schemes have been proposed to carry out effective quantum control of diverse systems and study the dynamics of these systems based on their natural timescales from the picoseconds (10-12 s), femtosecond (10-15 s) to attosecond (10-18 s) regimes. The goals of these various studies depend on the desired application, for instance in Photochemistry a long standing objective is achieving selective population transfer from an initial state to a desired target state with little or no diminution in the energy transferred. In quantum computation, a central issue is the excitation of unoccupied Rydberg states with numerous proposals for its use in the design and implementation of robust fast quantum gates. Also, since the advent of the generation of attosecond XUV pulses, doors have been opened for achieving control of atomic-scale electron dynamics and observing them in real-time. This thesis explores the modelling of dynamical light-matter interaction processes, like effective population inversion and generation of vibrational coherences in atoms and molecules, on their fundamental timescales using the density matrix (DM) theory under and beyond the rotating wave approximation (RWA). The thesis begins by introducing the concept of coherent control of simple quantum systems based on the DM formalism and expands the application to a more complex Oxazine system. Multiphoton p-pulse scheme is demonstrated for the control of population transfer in multilevel systems, for example with a trichromatic p-pulse having a set of areas v3 p, 2p and v3 p, complete population transfer in a four level system can be achieved. The aforementioned scheme is used to achieve effective control of low-lying Rydberg states in rubidium atoms, demonstrating how the effective control can be crucially affected by numerous physical processes. One main advantage of the density matrix approach over other theoretical approaches is that it allows the possibility of easily computing relaxation terms and other physical parameters critical to successful coherent control. The DM formalism is shown to be successful in properly describing the enhancement effects in atoms and complex molecular systems. It is robust in coherent control and quantum control spectroscopy (QCS) schemes and is extendable to numerous systems and geometric configurations. In the last part of the thesis, experiments on laser dressing processes in attosecond transient absorption spectroscopy are compared to numerical simulations using the DM analysis beyond the RWA. The research in this thesis opens a pathway to numerous studies using the DM formalism for applications in diverse fields of femtochemistry, attophysics, high precision spectroscopy and quantum information processing.