Quantum control of binary and many-body interactions in ultracold molecular gases

Ultracold molecules are expected to find applications in cold chemistry, quantum phases, precision measurements and quantum information. In this thesis three novel applications of cold molecules are studied. First the thesis presents a general method for coherent control of collisions between non-i...

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Main Author: Herrera, Felipe Andres
Language:English
Published: University of British Columbia 2012
Online Access:http://hdl.handle.net/2429/42542
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spelling ndltd-UBC-oai-circle.library.ubc.ca-2429-425422018-01-05T17:25:51Z Quantum control of binary and many-body interactions in ultracold molecular gases Herrera, Felipe Andres Ultracold molecules are expected to find applications in cold chemistry, quantum phases, precision measurements and quantum information. In this thesis three novel applications of cold molecules are studied. First the thesis presents a general method for coherent control of collisions between non-identical particles. It is shown that by preparing two alkali-metal atoms in a superposition of hyperfine states, the elastic-to-inelastic cross section ratio can be manipulated at ultracold temperatures by tuning laser parameters in the presence of a magnetic field. The static field is needed to induce quantum interference between scattering states. Extensions of this scheme for ultracold molecular reactive scattering are discussed. Second, the thesis describes rotational excitons and polarons in molecular ensembles trapped in optical lattices. Rotational excitons can be manipulated using static electric and magnetic fields. For a one-dimensional molecular array with substitutional impurities any localized exciton state can be delocalized by applying a suitable electric field. The electric field induces correlations between diagonal and off-diagonal disorder. It is also shown that the translational motion of polar molecules in an optical lattice can lead to phonons. The lattice dynamics and the phonon spectrum depend on the strength and orientation of a static electric field. An array of polar molecules in an optical lattice can be described by generalized polaron model with tunable parameters including diagonal and off-diagonal exciton-phonon interactions. It is shown that in a strong electric field the system is described by a generalized Holstein model, and at weak electric fields by the Su-Schrieffer-Heeger (SSH) model. The possibility of observing a sharp polaron transition in the SSH model using polar alkali-metal dimers is discussed. Finally, the thesis presents a method to generate entanglement of polar molecules using strong off-resonant laser pulses. Bipartite entanglement between alkali-metal dimers separated by hundreds of nanometers can be generated. Maximally entangled states can be prepared by tuning the pulse intensity and duration. A scheme is proposed to observe the violation of Bell’s inequality based on molecular orientation correlation measurements. It is shown that using a combination of microwave and off-resonant optical pulses, arbitrary tripartite and many-particle states can be prepared. Science, Faculty of Chemistry, Department of Graduate 2012-06-22T17:07:43Z 2012-06-22T17:07:43Z 2012 2012-11 Text Thesis/Dissertation http://hdl.handle.net/2429/42542 eng Attribution-ShareAlike 3.0 Unported http://creativecommons.org/licenses/by-sa/3.0/ University of British Columbia
collection NDLTD
language English
sources NDLTD
description Ultracold molecules are expected to find applications in cold chemistry, quantum phases, precision measurements and quantum information. In this thesis three novel applications of cold molecules are studied. First the thesis presents a general method for coherent control of collisions between non-identical particles. It is shown that by preparing two alkali-metal atoms in a superposition of hyperfine states, the elastic-to-inelastic cross section ratio can be manipulated at ultracold temperatures by tuning laser parameters in the presence of a magnetic field. The static field is needed to induce quantum interference between scattering states. Extensions of this scheme for ultracold molecular reactive scattering are discussed. Second, the thesis describes rotational excitons and polarons in molecular ensembles trapped in optical lattices. Rotational excitons can be manipulated using static electric and magnetic fields. For a one-dimensional molecular array with substitutional impurities any localized exciton state can be delocalized by applying a suitable electric field. The electric field induces correlations between diagonal and off-diagonal disorder. It is also shown that the translational motion of polar molecules in an optical lattice can lead to phonons. The lattice dynamics and the phonon spectrum depend on the strength and orientation of a static electric field. An array of polar molecules in an optical lattice can be described by generalized polaron model with tunable parameters including diagonal and off-diagonal exciton-phonon interactions. It is shown that in a strong electric field the system is described by a generalized Holstein model, and at weak electric fields by the Su-Schrieffer-Heeger (SSH) model. The possibility of observing a sharp polaron transition in the SSH model using polar alkali-metal dimers is discussed. Finally, the thesis presents a method to generate entanglement of polar molecules using strong off-resonant laser pulses. Bipartite entanglement between alkali-metal dimers separated by hundreds of nanometers can be generated. Maximally entangled states can be prepared by tuning the pulse intensity and duration. A scheme is proposed to observe the violation of Bell’s inequality based on molecular orientation correlation measurements. It is shown that using a combination of microwave and off-resonant optical pulses, arbitrary tripartite and many-particle states can be prepared. === Science, Faculty of === Chemistry, Department of === Graduate
author Herrera, Felipe Andres
spellingShingle Herrera, Felipe Andres
Quantum control of binary and many-body interactions in ultracold molecular gases
author_facet Herrera, Felipe Andres
author_sort Herrera, Felipe Andres
title Quantum control of binary and many-body interactions in ultracold molecular gases
title_short Quantum control of binary and many-body interactions in ultracold molecular gases
title_full Quantum control of binary and many-body interactions in ultracold molecular gases
title_fullStr Quantum control of binary and many-body interactions in ultracold molecular gases
title_full_unstemmed Quantum control of binary and many-body interactions in ultracold molecular gases
title_sort quantum control of binary and many-body interactions in ultracold molecular gases
publisher University of British Columbia
publishDate 2012
url http://hdl.handle.net/2429/42542
work_keys_str_mv AT herrerafelipeandres quantumcontrolofbinaryandmanybodyinteractionsinultracoldmoleculargases
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