EDP Sciences eBooks

Ultra-cold atoms, ions, molecules and quantum technologies

Hélène Perrin, Robin Kaiser, Michèle Leduc

Published Dec 31, 2022• 0 citations

Abstract

Physicists know how to produce gases at a few billionths of a degree above absolute zero. The cooling methods apply not only to atoms but also to ions and molecules. This field of research has three times been awarded the Nobel Prize. The field experienced remarkable growth when experimentalists learned how to vary at will the interactions between particles, trapping them with optical tweezers or in optical gratings with adjustable geometry. Artificial crystals made of atoms or molecules can be built to simulate the structure of matter and elucidate some of its magnetic properties, hopefully contributing to the understanding of high-temperature superconductivity. The phenomenon of quantum entanglement is the basis for new devices for the storage and transmission of quantum information. Spectacular progress is constantly being made in metrology. For example, ultra-cold atom or ion clocks measure time to better than one second over the lifetime of the Universe. New types of industrial gravimeters and gyroscopes are improving the sensitivity of seismology and navigation in space. In addition, the extreme precision of the measurements allows tests of the fundamental laws of physics, such as quantum electrodynamics, Lorentz invariance or possible variations of the fundamental constants. The field of ultra-cold particles has now reached the stage where it provides insights in the fields of condensed matter, chemistry and even cosmology.

DOI: 10.1051/978-2-7598-2745-9

Related papers

Ultra-cold atoms, ions, molecules and quantum technologies

Hélène Perrin, Robin Kaiser, Michèle Leduc

EDP Sciences eBooksDec 31, 20221 citation

Preamble

Robin Kaiser, Michèle Leduc, Hélène Perrin

Forty years ago, twenty years after the discovery of the laser, physicists were developing laser cooling methods for ions trapped in electromagnetic fields.From the 1980s onwards, these techniques were refined and extended to atoms, thanks to the audacity and inventiveness of a generation of pioneering researchers.Actually, it was necessary to succeed simultaneously in trapping and cooling samples of atomic gases in a vacuum at a distance from any wall.Spectacular results followed and extraordinarily low temperatures were quickly reached, very close to absolute zero.The field of "cold atoms" was born, rewarded by successive Nobel prizes, first of which was awarded in 1997 to William D. Phillips, Steven Chu and Claude Cohen-Tannoudji, last in 2022 to Alain Aspect.Gaseous samples of a few thousand to a few billion atoms can be prepared at a few millionths of a degree above absolute zero, which means that the particles move at extremely low speed, of the order of centimetres per second.At these extreme temperatures, the behaviour of matter changes and its properties can only be described using quantum mechanics and the wave properties of particles.New physical phenomena have been discovered and innovations have followed the theoretical and experimental progress of the research.Initially imagined as a wonderful method for perfecting atomic physics, cold atoms have gradually proved to be powerful tools for research in cross-cutting fields of physics, such as condensed matter and even high-energy physics.These atoms are now referred to as 'quantum gases' at such low temperatures that their collective behaviour is modified by the laws of quantum mechanics.

EDP Sciences eBooksDec 31, 20220 citations

Quantum simulation ‐ an exciting adventure

R. Blatt, Immanuel Bloch, J. I. Cirac +1 more

Quantum many-body systems, as they appear in different branches of physics and chemistry, are very hard to simulate. The number of parameters defining their quantum states grows exponentially with the number of constituents. This prevents us from exploring and investigating relevant problems involving relatively small numbers of subsystems even with the help of the most powerful supercomputers. Richard Feynman already noticed this difficulty back in 1981 when he wrote his visionary paper “Simulating Physics with Computers” [Int. J. Theor. Phys. 21:6/7, 467 (1982)]. There, he proposed to use quantum systems (as opposed to classical computers) to perform the simulation and in this way to circumvent the need to store and compute a colossal number of parameters, necessary to describe the pertaining superpositions. What was a visionary idea at that time has become a very active field of research in the last few years. The extraordinary progress of both theoretical and experimental research in quantum physics allows us now to tame, control, and manipulate various quantum systems with unprecedented precision. Laser, magnetic, electronic and other technologies enable us to arrange quantum subsystems in different geometries, modify their interactions, and detect them. This allows us to engineer Hamiltonians and emulate systems displaying some of the most intriguing quantum phenomena. This tremendous progress is, to a large extent, due to the pioneering work of many researchers during the last twenty to thirty years. Here, the investigations of basic phenomena with one or few atoms or photons were of particular impact. The degree of control achieved in the experiments has enabled the observation of mind-boggling quantum effects, related to the superposition principle or to entangled states, and their disappearance due to decoherence. In fact, the 2012 Nobel Prize has been awarded to two scientists, S. Haroche and D. Wineland, for such ground-breaking experiments. Such experiments, often in combination with laser cooling of atoms or ions and Bose-Einstein condensation, have formed one of the pillars on which the field of quantum simulations is being established. Quantum simulations with cold atoms, either in magnetic traps or in optical lattices, with trapped ions, with photons, with superconducting devices, with quantum dots, etc., have been theoretically proposed and experimentally considered by many researchers. Most of the proposals so far deal with problems in condensed matter physics that are either difficult to tackle with modern supercomputers or are difficult to observe in solid state systems. This has established a very close link between different disciplines, like atomic, molecular, and optical (AMO) physics, and condensed matter physics. Although some of the experiments are still in their infancy, and a lot of research is still needed, the extraordinary progress made in all these research areas during the last few years makes us feel confident that in the not too distant future quantum simulators will provide a key tool to investigate many-body quantum systems. Furthermore, we also expect that quantum simulators will help quantum physicists to establish new and fruitful links to other scientific communities, like high-energy physics or quantum chemistry. The present special issue contains various review papers as well as research papers on quantum simulations. It starts out with two papers written by last year's Nobel Prize winners describing their foundational work (Wineland, p. 739 and Haroche, p. 763). The issue continues with three thorough, invited review papers covering different topics on quantum simulations. The first one reviews recent theoretical proposals to use cold atoms in optical lattices to simulate lattice gauge theories of the sort that appear in high-energy physics (U.-J. Wiese, p. 783). The second covers both theoretical proposals and experimental demonstrations of cold-atom systems to simulate the physics of matter in the presence of gauge fields, displaying so-called topological phenomena, which so far have only been observed in solid-state systems (I. Spielman, p. 794). The third one contains an extensive overview and new proposals to perform a broad range of quantum simulations using quantum dot systems (P. Barthelmy et al., p. 813). The issue also includes six original papers with a variety of theoretical proposals as well as the introduction of novel theoretical techniques related to the field of quantum simulation. The field of quantum simulations is just starting, but we are confident that it will soon generate an even larger plethora of new ideas and discoveries, trigger interdisciplinary research, and lead us to the adventure of describing and understanding the quantum world. We hope that this special issue will help future researchers in such an exciting adventure. Rainer Blatt received his PhD degree in physics from the University of Mainz in 1981. As a postdoctoral fellow he worked on atomic beam cooling in Boulder, CO and later as a research assistant in Hamburg with single trapped ions. In 1995 he accepted a chair in experimental physics at the University of Innsbruck working on quantum information processing with trapped ions. Since 2003 he is also scientific director at the Institute for Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences. Immanuel Bloch received his PhD degree in physics from the Ludwig Maximilians University of Munich in 2000. As a junior group leader, he continued in Munich starting his work on ultracold quantum gases in optical lattices. In 2008 he was appointed scientific director of the newly founded division on Quantum Many-Body Systems at the Max Planck Institute of Quantum Optics. Since 2009 he also holds a chair in quantum optics at the Ludwig-Maximilians University of Munich. Ignacio Cirac received his PhD degree in physics from the Universidad Complutense de Madrid in 1991. He was professor at the Universities of Castilla-La Mancha and Innsbruck from 1991–1996 and 1996–2001, respectively. In 2001 he joined the Max-Planck Institute of Quantum Optics, where he leads the Theory Division. His current research interests include quantum information theory and quantum optics. Peter Zoller obtained his doctorate from the University of Innsbruck in 1977. He was Max Kade Fellow at the University of Southern California from 1978/79, and was JILA visiting Fellow 1981/82 and 1988. In 1990 he became JILA Fellow and professor of physics at the University of Colorado. At the end of 1994, he accepted a chair at the University of Innsbruck, where he has worked ever since. Since 2003, he has also held the position of Scientific Director at the Institute for Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences.

Annalen der PhysikNov 1, 20133 citations

The quantum world of ultra-cold atoms

William D. Phillips, Christopher J. Foot

Introduction This chapter describes remarkable new experiments that have been made possible through recent advances in laser cooling of atoms. Cooling of atoms in a gas by laser light is in itself surprising and this technique is important in a range of applications. In particular the experiments described here take atoms that have been laser cooled and then use other methods to reach even lower temperatures, at which wonderful and fascinating quantum effects occur. As well as revealing new phenomena, these experiments explore the deep analogies between the roles played by light waves in lasers and matter waves. These techniques are widely accessible and enable skilled researchers in laboratories all over the world to explore exciting new physics. The key physics and techniques of laser cooling are described in depth in Chapter 6. What is “temperature”? We use the words “cold” and “hot” every day; for example to refer to the temperature of the air outside. But what do “cold” and “hot” mean for the air’s molecules? Broadly speaking, we can say that atoms in a hot gas move faster than those in a cold gas and that cooling, by taking energy out of the gas, slows the atoms down. In this description of the gas as a collection of atoms behaving like billiard balls, or little hard spheres, the lowest possible temperature occurs when the atoms stop moving but, as we shall see, this picture does not give an accurate description at very low energies, for which quantum effects become important. In this chapter we will look at the fascinating properties of atomic gases cooled to temperatures within one millionth of a degree Kelvin from absolute zero. We shall use the term “ultra-cold” to refer to such extremely low temperatures that have only recently been achieved in experiments on atomic gases. The techniques used to cool liquids and solids have a longer history and have made available a different set of possibilities (see Chapter 8). Note that most of this chapter refers to gases in which the individual particles are atoms, but the general statements about temperature scales apply equally well to gases of molecules, e.g. air, whose major constituents, oxygen and nitrogen, exist as diatomic molecules.

Cambridge University Press eBooksFeb 13, 20060 citations

Focus on Cold and Ultracold Molecules

Lincoln D. Carr, Jun Ye

Cold and ultracold molecules are the next wave of ultracold physics, giving rise to an exciting array of scientific opportunities, including many body physics for novel quantum phase transitions, new states of matter, and quantum information processing. Precision tests of fundamental physical laws benefit from the existence of molecular internal structure with exquisite control. The study of novel collision and reaction dynamics will open a new chapter of quantum chemistry. Cold molecules bring together researchers from a variety of fields, including atomic, molecular, and optical physics, chemistry and chemical physics, quantum information science and quantum simulations, condensed matter physics, nuclear physics, and astrophysics, a truly remarkable synergy of scientific explorations. For the past decade there have been steady advances in direct cooling techniques, from buffer-gas cooling to cold molecular beams to electro- and magneto-molecular decelerators. These techniques have allowed a large variety of molecules to be cooled for pioneering studies. Recent amazing advances in experimental techniques combining the ultracold and the ultraprecise have furthermore brought molecules to the point of quantum degeneracy. These latter indirect cooling techniques magnetically associate atoms from a Bose–Einstein condensate and/or a quantum degenerate Fermi gas, transferring at 90% efficiency highly excited Fano–Feshbach molecules, which are on the order of 10 000 Bohr radii in size, to absolute ground state molecules just a few Bohr across. It was this latter advance, together with significant breakthroughs in internal state manipulations, which inspired us to coordinate this focus issue now, and is the reason why we say the next wave of ultracold physics has now arrived. Whether directly or indirectly cooled, heteronuclear polar molecules offer distinct new features in comparison to cold atoms, while sharing all of their advantages (purity, high coherence, controllability, tunable interactions, no disorder, etc). First, they are more easily manipulated because of the strong response of their electric dipole moment to external electric fields, DC or AC. The electric dipole moment also creates the new aspect of long range interactions. Second, they have a rich internal structure, with vibrational and rotational states, fine or hyperfine structure, and Ω- or Λ-doublets. This internal structure allows for wonderful new possibilities in areas such as precision measurement and exquisite control of system dynamics. Therefore, although this focus issue contains a few articles on homonuclear molecules, more complex molecules such as benzene, and even a contribution on atomic chromium, which has a significant magnetic dipole moment, our main focus is on the heteronuclear polar case. This focus issue explores both direct and indirect cooling of mainly polar molecules, and the theory to support and inspire these advances. Thirty-eight research groups have contributed original work, and there are two review articles to complement these advances: the first covers cold and ultracold molecules broadly from few body to many body physics, including foundational theory, the technology to make them, and their scientific applications. The second is on the search for time variation of fundamental constants. The former review, which is comprehensive in nature, concludes with a list of open questions. This sets the tone for the focus issue, namely, openness, innovation, and possibility, an emphasis for which New Journal of Physics , an open-access journal of the highest quality, is especially fitted. Focus on Cold and Ultracold Molecules Contents Cold and ultracold molecules: science, technology and applications Lincoln D Carr, David DeMille, Roman V Krems and Jun Ye Ultracold molecules: new probes on the variation of fundamental constants Cheng Chin, V V Flambaum and M G Kozlov Probing the unitarity limit at low laser intensities Philippe Pellegrini and Robin Côté Single-photon molecular cooling Edvardas Narevicius, S Travis Bannerman and Mark G Raizen Quantum simulations of extended Hubbard models with dipolar crystals M Ortner, A Micheli, G Pupillo and P Zoller Collisional and molecular spectroscopy in an ultracold Bose–Bose mixture G Thalhammer, G Barontini, J Catani, F Rabatti, C Weber, A Simoni, F Minardi and M Inguscio Multi-channel modelling of the formation of vibrationally cold polar KRb molecules Svetlana Kotochigova, Eite Tiesinga and Paul S Julienne Formation of ultracold, highly polar X 1 Σ + NaCs molecules C Haimberger, J Kleinert, P Zabawa, A Wakim and N P Bigelow Quantum polarization spectroscopy of correlations in attractive fermionic gases T Roscilde, M Rodríguez, K Eckert, O Romero-Isart, M Lewenstein, E Polzik and A Sanpera Inelastic semiclassical collisions in cold dipolar gases Michael Cavagnero and Catherine Newell Quasi-universal dipolar scattering in cold and ultracold gases J L Bohn, M Cavagnero and C Ticknor Stark deceleration of lithium hydride molecules S K Tokunaga, J M Dyne, E A Hinds and M R Tarbutt Molecular vibrational cooling by optical pumping with shaped femtosecond pulses D Sofikitis, S Weber, A Fioretti, R Horchani, M Allegrini, B Chatel, D Comparat and P Pillet Deeply bound ultracold molecules in an optical lattice Johann G Danzl, Manfred J Mark, Elmar Haller, Mattias Gustavsson, Russell Hart, Andreas Liem, Holger Zellmer and Hanns-Christoph Nägerl Toward the production of quantum degenerate bosonic polar molecules, 41 K 87 Rb K Aikawa, D Akamatsu, J Kobayashi, M Ueda, T Kishimoto and S Inouye Influence of a Feshbach resonance on the photoassociation of LiCs J Deiglmayr, P Pellegrini, A Grochola, M Repp, R Côté, O Dulieu, R Wester and M Weidemüller The kinematic cooling of molecules with laser-cooled atoms Ken Takase, Larry A Rahn, David W Chandler and Kevin E Strecker Coherent collapses of dipolar Bose–Einstein condensates for different trap geometries J Metz, T Lahaye, B Fröhlich, A Griesmaier, T Pfau, H Saito, Y Kawaguchi and M Ueda High-energy-resolution molecular beams for cold collision studies L P Parazzoli, N Fitch, D S Lobser and H J Lewandowski Collisional effects in the formation of cold guided beams of polar molecules M Motsch, C Sommer, M Zeppenfeld, L D van Buuren, P W H Pinkse and G Rempe Towards sympathetic cooling of large molecules: cold collisions between benzene and rare gas atoms P Barletta, J Tennyson and P F Barker Efficient formation of ground-state ultracold molecules via STIRAP from the continuum at a Feshbach resonance Elena Kuznetsova, Marko Gacesa, Philippe Pellegrini, Susanne F Yelin and Robin Côté Emergent timescales in entangled quantum dynamics of ultracold molecules in optical lattices M L Wall and L D Carr Rotational state resolved photodissociation spectroscopy of translationally and vibrationally cold MgH + ions: toward rotational cooling of molecular ions K Højbjerre, A K Hansen, P S Skyt, P F Staanum and M Drewsen Collective transverse cavity cooling of a dense molecular beam Thomas Salzburger and Helmut Ritsch A Stark decelerator on a chip Samuel A Meek, Horst Conrad and Gerard Meijer Deceleration of molecules by dipole force potential: a numerical simulation Susumu Kuma and Takamasa Momose Ultracold molecules: vehicles to scalable quantum information processing Kathy-Anne Brickman Soderberg, Nathan Gemelke and Cheng Chin Magnetic field modification of ultracold molecule–molecule collisions T V Tscherbul, Yu V Suleimanov, V Aquilanti and R V Krems Spectroscopy of 39 K 85 Rb triplet excited states using ultracold a 3 Σ + state molecules formed by photoassociation J T Kim, D Wang, E E Eyler, P L Gould and W C Stwalley Pumping vortex into a Bose–Einstein condensate of heteronuclear molecules Z F Xu, R Q Wang and L You Intense atomic and molecular beams via neon buffer-gas cooling David Patterson, Julia Rasmussen and John M Doyle Dynamical properties of dipolar Fermi gases T Sogo, L He, T Miyakawa, S Yi, H Lu and H Pu Collisions of bosonic ultracold polar molecules in microwave traps Alexander V Avdeenkov Cold TiO(X 3 Δ)–He collisions Mei-Ju Lu and Jonathan D Weinstein Investigation of dephasing rates in an interacting Rydberg gas U Raitzsch, R Heidemann, H Weimer, B Butscher, P Kollmann, R Löw, H P Büchler and T Pfau Impact of electric fields on highly excited rovibrational states of polar dimers Rosario González-Férez and Peter Schmelcher Phase transition from straight into twisted vortex lines in dipolar Bose–Einstein condensates M Klawunn and L Santos Stimulating the production of deeply bound RbCs molecules with laser pulses: the role of spin–orbit coupling in forming ultracold molecules Subhas Ghosal, Richard J Doyle, Christiane P Koch and Jeremy M Hutson Sensitive measurement of m p / m e variance using vibrational transition frequencies of cold molecules Masatoshi Kajita

New Journal of PhysicsMay 14, 200975 citations

Cold molecules: Progress in quantum engineering of chemistry and quantum matter

John L. Bohn, Ana María Rey, Jun Ye

Cooling atoms to ultralow temperatures has produced a wealth of opportunities in fundamental physics, precision metrology, and quantum science. The more recent application of sophisticated cooling techniques to molecules, which has been more challenging to implement owing to the complexity of molecular structures, has now opened the door to the longstanding goal of precisely controlling molecular internal and external degrees of freedom and the resulting interaction processes. This line of research can leverage fundamental insights into how molecules interact and evolve to enable the control of reaction chemistry and the design and realization of a range of advanced quantum materials.

arXiv:1708.02806ScienceSep 7, 2017483 citations