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DWC Seminar Series 2017


 
The DWC is hosting a series of seminars and public lectures open for everyone to attend, details can be found below.  


what's on this week: 

The Dodd-Walls centre is proud to present a series of seminars hosted by our themes on different topics and everyone is welcome to attend.   Friday’s seminar is presented by Ricardo Gutierrez Jauregui from University of Auckland.   Ricardo will present the seminar in room 303.610 at the University of Auckland and this will also be available via Zoom. 

Title:       Dissipative Phases of Cavity-Mediated Photon Interactions

When:    Date: Friday 24 February, 12 noon (sharp) to 1.00pm

Room:    303.610, University of Auckland + remote locations via Zoom

                University of Otago – Room 320e, Dodd-Walls Centre, Science III

               

Anyone can join from anywhere with the use of a laptop or computer via Zoom.

 

Zoom Meeting ID: 478-489-695 

 

Abstract:

The exquisite control acquired over quantum systems in recent years has provided a playground for studies of transitions between different phases of light and matter[1;2]. The realization of the Bose-Einstein condensate opened the door for quantum optics experiments using matter waves, while the advent of circuit quantum electrodynamics has allowed for strongly interacting systems to be simulated by light fields[3]. However, due to dissipation, the duality between light and matter systems is not complete. Dissipation affects both the evolution and the physical properties of a quantum system in a fundamental way.

In this seminar we address the question of how phase transitions in equilibrium relate to their driven dissipative analogues. This is done by contrasting the phases acquired by a quasi-conservative system, interacting BEC in an optical trap, with a driven-dissipative system, two driven cavities presenting a Kerr nonlinearity. We present the phases the system can acquire in both scenarios. First, for the single cavity limit where tunnelling is suppressed, then for the full Hamiltonian where competition of J and g leads to different phases of the system. The effect of quantum fluctuations on the phases of the system is highlighted.

 

[1] M. Greiner, O. Mandel, T. Esslinger, T. W. Hansch, I. Bloch, Nature 415, 39 (2002).

[2] A. D. Greentree, C. Tahan, J. H. Cole, and L. C. L. Hollenberg, Nature Physics 2, 856 (2006).

[3] G. Kirchmair, B. Vlastakis, Z. Leghtas, S. E. Nigg, H. Paik, E. Ginossar, M. Mirrahimi, Lu. Frunzio, S. M. Girvin

 & R. J. Schoelkopf, Nature 495, 205209 (2013).

 

 

DWC Seminar Series 2017


 
The DWC is hosting a series of seminars and public lectures open for everyone to attend, details can be found below.  


what's on this week: 

Presenter: Professor Sergej Flach from Institute for Basic Science, Daejeon.   Sergei will present the seminar at Massey (Albany) University and this will also be available via Zoom. 

Title:       Intermittent Many-Body Dynamics at Equilibrium

When:    Date: Friday 17 February, 12 noon (sharp) to 1.00pm

Room:    MS 3.32 (Massey Albany) + remote locations via Zoom

                University of Otago – Room 320e, Dodd-Walls Centre, Science III

Anyone can join from anywhere with the use of a laptop or computer via Zoom.

Zoom Meeting ID: 478-489-695

Abstract:

The equilibrium value of an observable defines a manifold in the phase space of an ergodic and equipartitioned many-body system. A typical trajectory pierces that manifold infinitely often as time goes to infinity. We use these piercings to measure both the relaxation time of the lowest frequency eigenmode of the Fermi-Pasta-Ulam chain, as well as the fluctuations of the subsequent dynamics in equilibrium. We show that previously obtained scaling laws for equipartition times are modified at low energy density due to an unexpected slowing down of the relaxation. The dynamics in equilibrium is characterized by a power-law distribution of excursion times far off equilibrium, with diverging variance. The long excursions arise from sticky dynamics close to regular orbits in the phase space. Our method is generalizable to large classes of many-body systems.