Quantum materials research with ultra-cold atoms and molecules

Overview of research theme

Since the advent of laser cooling and trapping, researchers have been using ultra-cold atomic samples for the study of various fundamental physical phenomena in the domains of quantum optics, quantum transport and quantum chaos. With the more recent achievement of Bose-Einstein condensation and degenerate Fermi gases, many-body quantum systems have become a subject of investigation for researchers in this field. One fascinating area of research is in the application of ultra-cold atomic gases to the study of strongly correlated quantum ensembles where, because of interactions, the states of the system can develop correlations and novel behaviors beyond the scope of mean field and independent particle descriptions. This research, on strongly correlated systems, has connections to analogous research in the condensed matter community.

Strongly correlated quantum systems

One of the primary goals of studying strongly correlated quantum systems experimentally is to bridge the fundamental gap which remains between materials experiments on and the theoretical description of certain exotic many-body phenomena including high-Tc superconductivity. The gap exists because of the impossibility of numerically simulating a highly-entangled, many-body quantum system using classical computers. By putting an ultra-cold gas of fermionic atoms into an optical crystal or optical lattice formed by the interference pattern of intersecting laser beams, one can realize a physical system capable of behaving like the system of electrons (also fermions) in a superconducting crystal. Using these atomic systems, researchers hope to simulate the physics of superconductors and determine the essential conditions under which superconductivity persists at high temperatures. Approaching this and other long standing mysteries of condensed matter physics with cold atomic systems may provide additional information crucial to their final unraveling.

Why cold gases?

More generally, the application of ultra-cold atomic gases to the study of many-body systems is an area with relevance to quantum information technologies, quantum simulators and quantum computation, and fundamental condensed matter physics. Because of the freedom to introduce and control both the external confinement potentials and inter-particle interactions as well as the almost perfect isolation from the environment, these systems are well suited for the realization and study of many model quantum systems (Hamiltonians). In addition to providing a novel approach for the study of the long standing mysteries associated with high-Tc superconductivity, these atomic gases also provide an inspiring tool capable of creating completely new and unexplored experimental systems whose realization and study will no doubt reveal exotic and unanticipated phenomena further enriching and advancing the frontiers of quantum materials and condensed matter physics.

Our focus

We are pursuing the experimental observation of both few and many-body quantum effects using cold atoms and cold molecules formed from cold atoms. Our goals include: (i) building the experimental tools to control the interactions between Rb and Li atoms (using both external magnetic and electric fields) and using these tunable interactions to study the dynamics of strongly interacting fermi gases and bose-fermi mixtures; (ii) building the experimental tools to create and study many-body systems realized with ultra-cold molecules, including Li2 and RbLi dimers.

Associated publications

Gene Polovy, Erik Frieling, Denis Uhland, Julian Schmidt, and Kirk W. Madison
Quantum-state-dependent chemistry of ultracold Li2 dimers
Phys. Rev. A 102, 013310 (2020)

Gene Polovy, Julian Schmidt, Denis Uhland, Erik Frieling, Kahan Dare, and Kirk W. Madison
Phase noise reduction of mutually tunable lasers with an external acousto-optic modulator
JOSA B, Vol. 36, Issue 2, pp. 464-469 (2019)

Will Gunton
Photoassociation and Feshbach Resonance Studies in Ultra-Cold Gases of 6Li and Rb Atoms
Doctor of Philosophy, Dissertation – April 2016 || UBC-Circle Link to dissertation

William Bowden, Will Gunton, Mariusz Semczuk, Kahan Dare, and Kirk W. Madison
Dual Species Effusive Source and Zeeman Slower for Cold Atom Experiments
Rev. Sci. Instrum. 87, 043111 (2016) || http://arxiv.org/abs/1509.07460

Will Gunton, Gene Polovy, Mariusz Semczuk, Kirk W. Madison
Transparent Electrodes for High E-Field Production Using A Buried ITO Layer
Rev. Sci. Instrum. 87, 033113 (2016) || http://arxiv.org/abs/1508.04086

Will Gunton, Mariusz Semczuk, and Kirk W. Madison
A method for independent and continuous tuning of N lasers phase-locked to the same frequency comb
Optics Letters, vol. 40, pp. 4372-4375 (2015) || http://arxiv.org/abs/1506.00389

Mariusz Semczuk
Photoassociation spectroscopy of a degenerate Fermi gas of 6Li
Doctor of Philosophy, Dissertation – February 2015 || UBC-Circle Link to dissertation

William J. Bowden
An Experimental Apparatus for the Laser Cooling of Lithium and Rubidium
Master of Science, Thesis – October 2014

Mariusz Semczuk, Will Gunton, William Bowden, and Kirk W. Madison
Anomalous Behavior of Dark States in Quantum Gases of Li6
Phys. Rev. Lett. 113, 055302 (2014) || http://arxiv.org/abs/1407.7904 || local copy

Will Gunton, Mariusz Semczuk, Nikesh S. Dattani, and Kirk W. Madison,
High resolution photoassociation spectroscopy of the 6Li_2 A(1^1\Sigma_u^+) state,
Phys. Rev. A 88, 062510 (2013) || http://arxiv.org/abs/1309.5870

Michal Tomza, Kirk W. Madison, Robert Moszynski, Roman V. Krems
Chemical reactions of ultracold alkali dimers in the lowest-energy $^3\Sigma$ state,
Phys. Rev. A 88, 050701(R) (2013) || http://arxiv.org/abs/1308.4783

Will Gunton, Mariusz Semczuk, and Kirk W. Madison,
Realization of BEC-BCS crossover physics in a compact oven-loaded magneto-optic trap apparatus
Phys. Rev. A 88, 023624 (2013) || arXiv:1307.5445

Felipe Herrera, Kirk W. Madison, Roman V. Krems, Mona Berciu,
Investigating polaron phase transitions with polar molecules,
Phys. Rev. Lett. 110, 223002 (2013) || http://arxiv.org/abs/1212.6212

Mariusz Semczuk, Xuan Li, Will Gunton, Magnus Haw, Nikesh S. Dattani, Julien Witz, Arthur Mills, David J. Jones, and Kirk W. Madison,
High resolution photoassociation spectroscopy of the 6Li_2 1^{3}\Sigma_{g}^{+} state,
Phys. Rev. A 87, 052505 (2013) || http://arxiv.org/abs/1309.6662

B. Deh, W. Gunton, B. G. Klappauf, Z. Li, M. Semczuk, J. Van Dongen, and K. W. Madison
Giant Feshbach resonances in 6Li-85Rb mixtures
Phys. Rev. A 82, 020701(R) (2010)

A. K. Mills, Y.-F. Chen, K. W. Madison, and D. J. Jones,
A widely tunable, single frequency optical frequency synthesizer with a 100 kHz uncertainty,
J. Opt. Soc. Am. B 26, 1276-1280 (2009)

Z. Li and K.W. Madison,
Effects of Electric Fields on Heteronuclear Feshbach Resonances in Ultracold 6Li-87Rb Mixtures,
Phys. Rev. A 79, 042711 (2009) || arXiv:0902.2505

K. Ladouceur, B.G. Klappauf, J. Van Dongen, N. Rauhut, B. Schuster, A.K. Mills, D.J. Jones, and K.W. Madison,
Compact laser cooling apparatus for simultaneous cooling of lithium and rubidium,
J. Opt. Soc. Am. B 26, 210-217 (2009)

Z. Li, S. Singh, T. V. Tscherbul, K. W. Madison,
Feshbach resonances in ultracold 85Rb-87Rb and 6Li-87Rb mixtures
Phys. Rev. A 78, 022710 (2008) || September 2008 issue of Virtual Journal of Quantum Information || http://arxiv.org/abs/0807.0417

A. K. Mills, Y.-F. Chen, J. Jiang, K. W. Madison, and D. J. Jones,
Using Difference Frequency Generation to Lock a CW Visible Laser to a Fiber Laser Frequency Comb,
Proceedings of Quantum Electronics and Laser Science Conference and Photonic Applications Systems Technologies || Optical Society of America, Technical Digest (CD), (2008), paper CFA4. || another link