Adolfo del Campo
Quantum Lunch Location:
T-Division Conference Room, TA-3,
Building 123, Room 121
Quantum Institute: Visitor Schedule
The Quantum Lunch is regularly held on Thursdays in the Theoretical Division Conference Room, TA-3, Building 123, Room 121.
The organizing committee includes Malcolm Boshier (P-21), Adolfo del Campo (T-4 & CNLS), Michael Di Rosa (C-PCS), Armin Rahmanisisan (T-4 & CNLS), Changhyun Ryu (P-21) , Nikolai Sinitsyn (T-4), Rolando Somma (T-4), Christopher Ticknor (T-1), and Wojciech Zurek (T-4).
For more information, or to nominate a speaker, contact Adolfo del Campo.
To add your name to the Quantum Lunch email list, contact Ellie Vigil.
Thursday June 27, 2013
12:30 PM - 2:00 PM
Speaker: Jonathan Keeling (University of St Andrews)
Technical Host: Adolfo del Campo
TOPIC: Non-equilibrium phases of coupled matter-light systems
Questions about the collective behaviour of large numbers of atoms (or
artificial atoms) interacting with radiation have a long history,
dating back at least to the work of Dicke in 1954. A particularly
notable result is that above a critical coupling strength, the ground
state of the Dicke model is predicted to become one with a non-zero
photon number. However, complications arise from when the diamagnetic
coupling (the A^2 term) between light and matter is included,
suggesting that the Dicke phase transition may be an unobservable
artifact. Nonetheless, in 2010, this transition was observed  in a
system of cold atoms in an optical cavity, where a generalised Dicke
model arises as the effective description of this non-equilibrium
Following a brief review of the history of problems of phase
transitions in coupled matter-light systems, I will discuss examples
of collective behaviour in systems of cold atoms  and
superconducting qubits . These will illustrate various different
approaches to pumping and decay, and illustrate the similarities and
differences between the equilibrium phase diagram and the dynamical
phase diagram of these non-equilibrium systems.
 K. Baumann, C. Guerlin, F. Brennecke and T. Esslinger, Nature 464,
 J. Keeling, M. J. Bhaseen and B. D. Simons, Phys. Rev. Lett 105
043001 (2010); M. J. Bhaseen, J. Mayoh, B. D. Simons and
J. Keeling, Phys. Rev. A 85, 013817 (2012).
 F. Nissen, S. Schmidt, M. Biondi, G. Blatter, H. E. Türeci, and
J. Keeling, Phys. Rev. Lett. 110 203602 (2012)