Theoretical Atomic, Molecular, and Optical Physics

Most of the polyatomic systems studied in physics, chemistry, and biology are quite complex. One of the approaches to understanding their properties is "top-down", i.e. by isolating individual parts of the system and studying its behavior at ever smaller scales. However, strong correlations between the constituent parts, their couplings to the environment, and a general lack of control over the "realistic" systems, makes such a separation challenging.

Recently, we witnessed a tremendous progress in the experimental study of controllable quantum systems, such as cold atoms, molecules, and ions; photons coupled to cavities; defects in solids; superconducting circuits; mechanical oscillators; as well as numerous hybrid systems. In several instances, scientists have reached an ultimate degree of controllability, allowing to prepare particles in a desired quantum state, control their evolution by engineering the microscopic Hamiltonian, and measure the resulting collective states at a single-particle level. In addition, it has become possible to "open" the system in a tunable way, by coupling it to a controlled environment.

This provides a complete toolbox for pursuing the "bottom-up" approach, i.e. studying how the many-body phenomena emerge with an increasing number of particles. At the moment, such bottom-up studies of quantum phenomena coalesce into a new research area, whose rapid development is fostered by an intense collaboration of theorists and experimentalists. The research of Mikhail Lemeshko aims at advancing this research area by theoretically studying strongly-interacting and far-from-equilibrium systems based on ultracold atoms, molecules, and ions, along the lines outlined below.

Contact

Mikhail Lemeshko
Institute of Science and Technology Austria (IST Austria)
Am Campus 1
A – 3400 Klosterneuburg

Phone: +43 (0)2243 9000-6001
Fax: +43 (0)2243 9000 2000
E-mail: mikhail.lemeshko@remove-this.ist.ac.at

CV and publication list

Lemeshko Group website

Assistant

Dana Domnisor

Phone: +43 (0)2243 9000-1096
E-mail: dana.domnisor@remove-this.ist.ac.at

Team

  • Clemens Jochum, Intern
  • Jan Kaczmarczyk, Postdoc (ISTfellow)
  • Laleh Safari, Postdoc (ISTfellow)
  • Bikashkali Midya, Postdoc (ISTfellow)

Open Positions

I am looking for highly motivated PhD students and postdocs interested in theoretical research at the interface of atomic, molecular, optical, chemical, and condensed matter physics. If you are interested in joining my research group as a PhD student, please apply to the IST graduate school (you are welcome to contact me first); if you are interested in working with me as a postdoc, please e-mail me directly.

Selected Projects

• Studying open quantum systems and understanding how dissipation acts at the microscopic scale.

In a number of applications, such as quantum information processing and coherent spectroscopy, coupling to a fluctuating bath leads to undesired decoherence. In some other cases, however, interaction with the environment results in novel effects, such as the localization transition in the spin-boson model, or enhanced efficiency of energy transfer in photosynthetic complexes. The controllability offered by modern ultracold experiments allows not only to understand the effects of dissipation, but also to make use of it as a convenient resource for quantum state preparation.

As a recent example, we have shown that bonding between ultracold atoms or molecules can arise due to non-conservative forces induced by dissipation [1]. Remarkably, such "dissipatively-bound molecules" can be formed even if interparticle interactions are purely repulsive. An extension of this idea to a many-particle system results in a dissipation-induced spatial long-range order in ultracold gases [2].

• Many-body physics of ultracold quantum gases: quantum simulation of phenomena taking place in "conventional" condensed matter physics, as well as engineering Hamiltonians featuring novel, unobserved phenomena.

Our recent research concerned the many-body behavior of quadrupolar quantum gases [3] and preparation of strongly interacting states of polar molecules in optical lattices [4].

• Developing techniques to manipulate atoms, molecules, and interactions between them with electromagnetic fields [5, 6], and applying this knowledge to the fundamental directions described above, as well as to practical applications, such as using cold molecules as electromagnetic field sensors [7].

Selected Publications

[1] M. Lemeshko, H. Weimer
Dissipative binding of atoms by non-conservative forces,
Nature Communications 4, 2230 (2013)

[2] J. Otterbach, M. Lemeshko
Dissipative Preparation of Long-Range Spatial Order in Rydberg-Dressed Bose-Einstein Condensates, Phys. Rev. Lett. 113, 070401 (2014)

[3] S. G. Bhongale, L. Mathey, E. Zhao, S. F. Yelin, M. Lemeshko
Quantum phases of quadrupolar Fermi gases in optical lattices,
Phys. Rev. Lett., 110, 155301 (2013)

[4] M. Lemeshko, R. V. Krems, H. Weimer.
Non-adiabatic preparation of spin crystals with ultracold polar molecules,
Phys. Rev. Lett. 109, 035301 (2012)

[5] M. Lemeshko, R. V. Krems, J. M. Doyle, S. Kais
Manipulation of molecules with electromagnetic fields
Molecular Physics 111, 1648 (2013)arXiv:1306.0912

[6] M. Lemeshko
Shaping interactions between polar molecules with far-off-resonant light
Phys. Rev. A 83, 051402 (Rapid Comm.) (2011)

[7] S. V. Alyabyshev, M. Lemeshko, R. V. Krems
Sensitive imaging of electromagnetic fields with paramagnetic polar molecules, Phys. Rev. A 86, 013409 (2012)

Career

Since 2014 Assistant Professor, IST Austria
2011-2014 ITAMP postdoctoral fellow, Harvard University, Cambridge, MA, USA
2011 PhD in AMO physics, Fritz Haber Institute of Max Planck Society, Berlin
2007 MSc in Condensed Matter Physics, Southern Federal Univ, Rostov, Russia

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