NIST Physics Laboratory http://physics.nist.gov QIBEC seminars Transcripts of Quantum information/Bose-Einstein condensation (QIBEC) seminars at the National Institute of Standards and Technology. Transcripts of Quantum information/Bose-Einstein condensation (QIBEC) seminars at the National Institute of Standards and Technology. en-us Work of the U.S. Government - not subject to copyright no Charles Clark charles.clark@nist.gov science laser atom ion molecule electron string spin photon Bose Einstein Fermi Dirac condensate physics quantum Bran Flakes cryptography mathematics chemistry entanglement boson fermion microscopy government nanotechnology measurement qubit exchange Ana Maria Rey Fisica y Sociedad - Año Mundial de la Fisica 2005 En esta conferencia presento bajo un contexto apropiado para el público general algunas de las contribuciones de mi tesis de doctorado al campo de átomos fríos en redes ópticas. Mi tesis se dedicó particularmente a estudiar la transición cuántica de superfluido a aislante de Mott. Esta transición tiene lugar debido a la competencia entre la energía de movimiento y la energía de interacción. Aunque es un trabajo teórico se realizo en el contexto de experimentos encaminados en la implementación de un computador cuántico con átomos neutros. En esta presentación comienzo con una introducción básica al tema de átomos fríos, seguido de una visión general de los avances experimentales y teóricos mas recientes en el campo. Después presento brevemente un resumen de mi tesis concentrándome en dos puntos específicos: la dinámica de átomos selectivamente cargados cada tres pozos en una red unidimensional, y la inicialización de un registro cuántico. El primero fue motivado por la realización experimental de este sistema por el grupo del enfriamiento láser del NIST (Instituto Nacional de Estándares y Medidas). Después de demostrar como las teorías cinéticas estándares fallan en describir la dinámica de los átomos en la red selectivamente cargada, presento nuevos métodos capaces de describir adecuadamente la dinámica cuántica. Respecto al segundo punto, discuto como es posible a través de la transición de Mott generar una configuración en la red con exactamente un átomo por pozo haciendo uso apropiado del campo magnético presente en los experimentos. Presentado originalmente en la conferencia, Fisica y Sociedad - Año Mundial de la Fisica 2005, Simposio del Programa Nacional de Ciencias Basicas, Colciencias, Septiembre 5-7 /2005, Bogotá, Colombia. 00:16:03 no Fri, 12 May 2006 20:00:00 EST Ciencia Ana Maria Rey Fisica y Sociedad - Año Mundial de la Fisica 2005 En esta conferencia presento bajo un contexto apropiado para el público general algunas de las contribuciones de mi tesis de doctorado al campo de átomos fríos en redes ópticas. Mi tesis se dedicó particularmente a estudiar la transición cuántica de superfluido a aislante de Mott. Esta transición tiene lugar debido a la competencia entre la energía de movimiento y la energía de interacción. Aunque es un trabajo teórico se realizo en el contexto de experimentos encaminados en la implementación de un computador cuántico con átomos neutros. En esta presentación comienzo con una introducción básica al tema de átomos fríos, seguido de una visión general de los avances experimentales y teóricos mas recientes en el campo. Después presento brevemente un resumen de mi tesis concentrándome en dos puntos específicos: la dinámica de átomos selectivamente cargados cada tres pozos en una red unidimensional, y la inicialización de un registro cuántico. El primero fue motivado por la realización experimental de este sistema por el grupo del enfriamiento láser del NIST (Instituto Nacional de Estándares y Medidas). Después de demostrar como las teorías cinéticas estándares fallan en describir la dinámica de los átomos en la red selectivamente cargada, presento nuevos métodos capaces de describir adecuadamente la dinámica cuántica. Respecto al segundo punto, discuto como es posible a través de la transición de Mott generar una configuración en la red con exactamente un átomo por pozo haciendo uso apropiado del campo magnético presente en los experimentos. Presentado originalmente en la conferencia, Fisica y Sociedad - Año Mundial de la Fisica 2005, Simposio del Programa Nacional de Ciencias Basicas, Colciencias, Septiembre 5-7 /2005, Bogotá, Colombia. 00:16:57 no Fri, 12 May 2006 19:59:00 EST Ciencia Ana Maria Rey Fisica y Sociedad - Año Mundial de la Fisica 2005 En esta conferencia presento bajo un contexto apropiado para el público general algunas de las contribuciones de mi tesis de doctorado al campo de átomos fríos en redes ópticas. Mi tesis se dedicó particularmente a estudiar la transición cuántica de superfluido a aislante de Mott. Esta transición tiene lugar debido a la competencia entre la energía de movimiento y la energía de interacción. Aunque es un trabajo teórico se realizo en el contexto de experimentos encaminados en la implementación de un computador cuántico con átomos neutros. En esta presentación comienzo con una introducción básica al tema de átomos fríos, seguido de una visión general de los avances experimentales y teóricos mas recientes en el campo. Después presento brevemente un resumen de mi tesis concentrándome en dos puntos específicos: la dinámica de átomos selectivamente cargados cada tres pozos en una red unidimensional, y la inicialización de un registro cuántico. El primero fue motivado por la realización experimental de este sistema por el grupo del enfriamiento láser del NIST (Instituto Nacional de Estándares y Medidas). Después de demostrar como las teorías cinéticas estándares fallan en describir la dinámica de los átomos en la red selectivamente cargada, presento nuevos métodos capaces de describir adecuadamente la dinámica cuántica. Respecto al segundo punto, discuto como es posible a través de la transición de Mott generar una configuración en la red con exactamente un átomo por pozo haciendo uso apropiado del campo magnético presente en los experimentos. Presentado originalmente en la conferencia, Fisica y Sociedad - Año Mundial de la Fisica 2005, Simposio del Programa Nacional de Ciencias Basicas, Colciencias, Septiembre 5-7 /2005, Bogotá, Colombia. 00:16:36 no Fri, 12 May 2006 19:58:00 EST Ciencia John Sidles QIBEC Seminar 05/08/2006 This talk introduces a new technique for model order reduction in large-scale quantum spin simulations. The technique has three stages: first the deliberate introduction of noise into the simulation; then the conversion of that noise into an equivalent continuous measurement process; and finally the projection of the resulting quantum trajectory onto a product-sum manifold of Beylkin-Mohlenkamp type. The application of this technique is illustrated by numerical quantum trajectory simulations of single-spin detection by magnetic resonance force microscopy (MRFM). Excellent agreement with experimental results is obtained. It is shown that in the Markovian noise limit single-spin data statistics can be predicted in closed form to all orders, despite the nonlinearity of the underlying quantum model. A new closed-form positive P-representation of the thermal density matrix is derived as an auxiliary result. Large-scale quantum simulations of up to eighteen interacting spins are then presented, in the context of a spin-dust model that has no symmetries, no spatial ordering, and high temperature; the technique is found to work well even within this deliberately challenging model. Classical and quantum model order reduction (MOR) techniques are compared, and the invariance associated with Choi's Theorem is shown to be essential to quantum model order reduction. A surprising equivalence between compressed wave functions and cryptographic keys is noted, and as a proof-of-principle, the numerical spin-dust trajectories are used to implement a public key exchange protocol. A large class of quantum systems can be simulated in polynomial space and time by this method, with the main restriction that the noise level be large enough that the system being simulated is not running a quantum computation. 01:28:36 no Mon, 08 May 2006 20:00:00 EST magnetic force microscopy Joseph Traub QIBEC Seminar 04/05/2006 For the foreseeable future the number of qubits will be a crucial computational resource. We show how to lower bound the qubit complexity using the classical query complexity. We use this result to present a simple problem which cannot be solved on a quantum computer in the standard quantum setting with deterministic queries but can be solved on a classical computer using randomized queries (Monte Carlo). This suggests introducing a quantum setting with randomized queries. We apply this setting to high dimensional integration and to path integration. In particular, there is an exponential improvement in the qubit complexity of path integration using the quantum setting with randomized queries. We end by discussing future directions and where to learn more. 01:03:27 no Wed, 05 Apr 2006 20:00:00 EST helium superfluid Josepson Richard Packard QIBEC Seminar 03/29/2006 During the past few years arrays of nanometer sized apertures connecting reservoirs of superfluid helium have been found to exhibit properties described by the two Josephson equations. This talk will describe some of the experiments, in ³He below 1 mK, and in 4He near 2 K, which reveal the quantum nature of these weak links. Both of these superfluids exhibit Josephson oscillations, the so called "quantum whistle". As temperature rises, 4He weak link arrays morph continuously from a phase slip regime into a Josephson sine-like current-phase relation. It is still a mystery why these arrays exhibit quantum coherence over thousands of apertures. Sensitive rotation sensors, analogous to the superconducting dc-squid, have been demonstrated in both ³He and 4He. These matter-wave quantum interferometers may find multiple applications such as examining some fundamental interactions in nature, monitoring small changes in the Earth's motion, and navigating submarines. 01:31:58 no Wed, 29 Mar 2006 20:00:00 EST helium superfluid Josepson Gerard Milburn QIBEC Seminar 03/08/2006 Few-body interacting systems are generically nonlinear dynamical systems and exhibit a rich structure of fixed point bifurcations. In a quantum description fixed points correspond to stationary states, usually the ground state. How does the associated stationary state reflect the loss of stability of the corresponding fixed point in the classical description? Using a number of examples I will show that ground state entanglement is large for those parameter values at which a bifurcation occurs in the stability of the corresponding fixed point. Various examples will be used to illustrate this ¬correspondence principle­ including: two component BECs, coupled magnetic molecules, Jahn-Teller models and nano mechanical systems. I will also describe a similar class of phenomenon based on quantum versions of area preserving maps. These are more easily implemented on quantum computer systems, especially ion traps. Finally I will conclude with a discussion of the relation between entanglement at semiclassical bifurcations and quantum phase transitions. 01:33:36 no Wed, 08 Mar 2006 20:00:00 EST chaos entanglement phase transitions Carlos Sa de Melo QIBEC Seminar 03/01/2006 I will review briefly some old results of the evolution from BCS to BEC superfluidity in dilute Fermi gases, including critical temperature, order parameter amplitude, chemical potential, collective modes, and time dependent Ginzburg-Landau theory for the s-wave channel in three dimensions. Following this discussion, I will present new results for the BCS to BEC evolution of Fermi gases in the p-wave channel. I will make comparisons between s-wave and p-wave superfluidity and point out the main differences between the two cases. Lastly, I will discuss superfluidity of s-wave and p-wave Fermi gases in a restricted two-dimensional geometry (one dimensional optical lattice), where a Berezinskii-Kosterlitz-Thouless-type transition is proposed as the system evolves from the weak to the strong attraction limit. I will show that spontaneous vortex-antivortex pairs form and that they can condense into a vortex-antivortex lattice at lower temperatures. 01:22:53 no Wed, 01 Mar 2006 20:00:00 EST helium superfluid Josepson Rudolf Grimm QIBEC Seminar 02/08/2006 Transcript of the Quantum information/Bose-Einstein condensation (QIBEC) seminar of February 8, 2006. 01:18:18 no Wed, 08 Feb 2006 20:00:00 EST Efimov halo Borromean rings Sandro Stringari QIBEC Seminar 01/25/2006 The problem of the Casimir-Polder-Lifshitz force between an atom and the surface of a substrate is discussed. When the temperatures of the substrate and the environment are different, new physical phenomena arise, including the new decay law 1/z^3 of the force at large distances, which is slower than at thermal equilibrium. New experimental possibilities of measurement of the forces are discussed: the oscillations of a Bose-Einstein condensate near the surface, Bloch oscillations of fermions in an optical lattice and the phase evolution of a Bose-Einstein condensate in a double well trap. 01:30:20 no Fri, 27 Jan 2006 14:00:00 EST surface-atom interaction casimir force sapphire rubidium Mikkel Andersen QIBEC Seminar 01/18/2006 Transcript of the Quantum information/Bose-Einstein condensation (QIBEC) seminar of January 18, 2006. 01:13:03 no Fri, 20 Jan 2006 14:00:00 EST vortex angular momentum Bragg Steven Anlage QIBEC Seminar 01/11/2006 Transcript of the Quantum information/Bose-Einstein condensation (QIBEC) seminar of January 11, 2006. 01:32:16 no Fri, 13 Jan 2006 14:00:00 EST vortex angular momentum Bragg NIST Quantum Communication Testbed Team QIBEC Seminar 12/14/2005 Transcript of the Quantum information/Bose-Einstein condensation (QIBEC) seminar of December 14, 2005. 01:22:07 no Wed, 14 Dec 2005 21:00:00 EST cryptography broadband Fraunhofer photodetector gigabit ethernet cryptographic key Ennio Arimondo QIBEC Seminar 12/07/2005 Collisional properties of a mixture of Cs and Rb atoms in a magnetic trap at microK temperatures were studied. By selectively evaporating the Rb atoms using a radio-frequency field, sympathetic cooling of Cs down to a few microK was achieved. Microwave radiation was also applied selectively evaporate Rb or Cs atoms in different Zeeman states. The interspecies collisional cross section was determined through rethermalization measurements, leading to good agreement with a theoretical prediction of 595 a0 for the triplet s-wave scattering length for Rb in the F=2,mF=2 and Cs in the F=4,mF=4 magnetic states. The experimental results were analysed through a model for collisional properties of the mixture. By supposing that each atomic cloud was in thermal equilibrium the rethermalization process was modeled through differential equations for the two atomic temperatures. An alternative approach was based on the Monte Carlo simulations of the individual collisional processes. 01:11:12 no Mon, 12 Dec 2005 14:00:00 EST quantum Bose Einstein physics laser cooling rubidium caesium imaging atom molecule optics Jacob Taylor QIBEC Seminar 11/30/2005 Solid state approaches to quantum computation offer intriguing prospects for large scale integration and long term stability. However, achieving fault tolerant quantum computation entails significant mitigation of environmental couplings, which is particularly challenging in the solid state. We will discuss the theoretical and experimental development of a scalable architecture for solid-state quantum computation based on actively protected two electron spin states in quantum dots. Specifically, we find a universal set of gates for two-spin states that can be implemented using only local electrical control, with explicit suppression of hyperfine interactions, the dominant source of error. The architecture allows for a modular, hierarchical design, and includes autonomous control and non-local coupling using controlled electron transport. Fault tolerance properties of the architecture will be considered. 01:32:10 no Wed, 07 Dec 2005 14:30:00 EST quantum Bose Einstein physics laser cooling solid state imaging atom molecule optics Jennifer Sebby-Strabley and Marco Anderlini QIBEC Seminar 11/16/2005 Transcript of the Quantum information/Bose-Einstein condensation (QIBEC) seminar of November 16, 2005. 01:54:19 no Wed, 07 Dec 2005 14:25:00 EST quantum Bose Einstein physics laser cooling optical lattice imaging atom molecule optics Andrew Skinner QIBEC Seminar 11/09/2005 I develop a Born-Markov master equation for a chain of coupled spin-boson models. Each subsystem is treated as an effectively unbiased two-level system, or qubit, dissipating independently into an ohmic bath of oscillators. For a few qubits, I show how the low-temperature bath causes the chain to dissipate and decohere at selection-ruled rates that thermalize the chain. The independent dissipation of each qubit can induce entanglement and, in resonant transitions, can cause coherence to flow, along with the populations, into a less decoherent subspace. 01:47:12 no Wed, 07 Dec 2005 14:20:00 EST quantum Bose Einstein physics laser cooling superconductor imaging atom molecule optics Frederick Strauch QIBEC Seminar 10/26/2005 Many experimental groups have studied superconducting circuits specially designed to observe and manipulate the quantum mechanical states of (a macroscopic number of) Cooper pairs oscillating across Josephson tunnel junctions. Evidence observed so far includes quantum tunneling, energy level quantization (spectroscopy), and coherent oscillations (Larmor, Rabi, and Ramsey), in devices with multiple degrees of freedom (i.e. entanglement) and extended electromagnetic geometries (i.e. cavities). Alongside this significant progress remain many fundamental questions. Some recent experiments, for example, suggest significant new physics for Josephson junctions, while certain theories have developed classical analogies to multi-photon excitations and Rabi oscillations. This talk will critically survey these issues, including the question of what constitutes true evidence (i.e. proof) for quantum mechanical behavior. 01:46:25 no Wed, 07 Dec 2005 14:15:00 EST quantum Bose Einstein physics laser cooling superconductor imaging atom molecule optics Lincoln Turner QIBEC Seminar 10/19/2005 Almost all measurements of cold atoms are made optically with near-resonant light, with most being made with absorption imaging. A single photon has enough momentum to knock many thousands of atoms out of a condensate, and so absorption imaging destroys the cold atom sample. Off-resonant phase imaging greatly reduces absorption, allowing many sequential images of the same cloud. It has not been widely used as traditional phase imaging techniques require elaborate optics. I will describe how off-resonant images can be made with only a point-source of light and a CCD detector. Lenses (and their aberrations) are not needed, mis-focus is impossible and resolution down to 2-3 wavelengths should be practical. 01:04:40 no Wed, 07 Dec 2005 14:10:00 EST quantum Bose Einstein physics laser cooling holography imaging atom molecule optics Zachary Dutton QIBEC Seminar 10/12/2005 01:38:05 no Wed, 07 Dec 2005 14:05:00 EST quantum Bose Einstein physics laser cooling holography imaging atom molecule optics Jabez McClelland QIBEC Seminar 9/28/2005 Transcript of the Quantum information/Bose-Einstein condensation (QIBEC) seminar of August 31, 2005. 01:00:50 no Wed, 07 Dec 2005 14:00:00 EST quantum Bose Einstein physics laser cooling erbium atom molecule optics Yehuda Band QIBEC Seminar 9/21/2005 We consider the conversion of ultracold Fermi gases into diatomic molecule Bose gases using Feshbach resonance sweep experiments upon preparation of an incoherent mixture of equal populations of two internal states of the fermionic atoms. The preparation process produces a mixture of even and odd parity pair-states, where only even parity can produce molecules. Analysis of the dynamical equations of motion for the gas, supported by mean-field and many-body numerical results, shows that the dependence of the remaining atomic fraction on the sweep rate varies from exponential Landau-Zener behavior for a single pair of particles to a power-law dependence for large particle number. 01:52:26 no Thu, 01 Dec 2005 14:15:00 EST quantum Bose Einstein physics laser atom molecule optics Chui-ping Yang QIBEC Seminar 9/14/2005 Transcript of the Quantum information/Bose-Einstein condensation (QIBEC) seminar of August 31, 2005. 01:13:25 no Wed, 01 Dec 2005 14:15:00 EST quantum Bose Einstein condensate Josephson resonator Lin Tian QIBEC Seminar 9/7/2005 I present my recent work on the control of low frequency noise in solid-state devices with continuous measurement, and quantum teleportation with nanomechanical systems without photons. 01:45:32 no Thu, 01 Dec 2005 14:10:00 EST quantum Bose Einstein condensate solid state teleportation measurement molecule optics photon Indu Satija QIBEC Seminar 8/31/2005 Transcript of the Quantum information/Bose-Einstein condensation (QIBEC) seminar of August 31, 2005. 01:35:37 no Thu, 01 Dec 2005 14:00:00 EST quantum Bose Einstein condensate Mott insulator disorder physics laser atom molecule optics photon Hadley Lawler QIBEC Seminar 8/17/2005 Polaritons were originally considered within the context of the dielectric response of bulk systems, and its relation to the dispersion of fundamental solid-state excitations, such as excitons and optical phonons. More recently, excitonic cavity polaritons have been theoretically described and observed. These excitonic cavity polaritons represent a tunable Rabi coupling between a condensed matter excitation within a microstructure and a cavity-resonant electromagnetic mode. Like excitons, optical phonons possess well-characterized cross-sections with the electromagnetic field, but at lower energies and larger length and time scales. We present theory relevant to a phononic cavity polariton, discuss the prospects for the observation of such a system, and detail our progress toward the prediction of the Rabi coupling's variation with tunable parameters. While susceptibility-type measurements are a possible route for the detection of such a system, we emphasize the possibility of measuring the Rabi oscillation directly in the time domain using ultrafast lasers. 01:37:32 no Wed, 31 Aug 2005 14:20:00 EDT quantum Bose Einstein physics laser atom molecule optics polariton exciton photon phonon Rainer Dumke QIBEC Seminar 8/10/2005 By driving photoassociation transitions we form electronically excited molecules (Na2 ) from ultracold (50-300 microkelvin) Na atoms. Using a second laser to drive transitions from the excited state to a level in the molecular ground state, we are able to split the photoassociation line and observe features with a width smaller than the natural linewidth of the excited molecular state. The quantum interference which gives rise to this effect is analogous to that which leads to electromagnetically induced transparency in three level atomic systems, but here one of the ground states is a pair of free atoms while the other is a bound molecule. The linewidth is limited primarily by the finite temperature of the atoms. To generate even lower temperatures we have setup an all optical BEC experiment. 01:31:10 no Tue, 30 Aug 2005 14:20:00 EDT quantum Bose Einstein physics laser atom molecule optics photoassociation Paul Julienne QIBEC Seminar 8/3/2005 Transcript of the Quantum information/Bose-Einstein condensation (QIBEC) seminar of August 3, 2005 01:49:12 no Mon, 29 Aug 2005 14:10:00 EDT quantum Bose Einstein physics laser atom molecule optics Xiao-Gang Wen QIBEC Seminar 7/27/2005 Recent advances in condensed matter theory have revealed that spin models can realize new and exotic phases of matter via a simple physical mechanism, known as "string-net condensation." These new phases of matter have the unusual property that their collective excitations are gauge bosons and fermions. In some cases, the collective excitations can behave just like the photons, electrons, gluons, and quarks in our vacuum. This suggests that photons, electrons, and other elementary particles may originate from string-net condensation in our vacuum. In addition, the string-net picture indicates how to make artificial photons, artificial electrons, and artificial quarks and gluons in condensed matter systems. 01:41:16 no Mon, 15 Aug 2005 14:00:00 EDT quantum Bose Einstein physics laser atom molecule optics electron photon spin string The NIST Physics Laboratory The Quantum information/Bose-Einstein condensation seminar series Welcome to the enhanced podcasts of the Quantum Information and Bose-Einstein Condensation lecture series at the National Institute of Standards and Technology, where we bring to you discussion-filled lectures on the hottest topics in the ultracool. This is your portal to the exhilarating world of ultracold atomic physics, where the pristine quantum behavior at the atomic scale confronts the complexities of many-body physics to help unlock the secrets of quantum mechanics at the macroscopic scale. Activate "show song artwork" (fourth button from left in the lower left corner of the iTunes interface) to see speakers' slides in synchronism with the presentation. Now sit back and enjoy the show! 00:00:55 no Mon, 15 Aug 2005 12:00:00 EDT quantum Bose Einstein physics laser atom molecule optics electron photon spin string NIST seminar