CQED

The concept of temperature is critical in describing many physical phenomena, such as the transition from one phase of matter to another. Turn the temperature knob and interesting things can happen. But other knobs might be just as important for studying some phenomena. One such knob is chemical potential, a thermodynamic parameter first introduced in the nineteenth century by scientists for keeping track of potential energy absorbed or emitted by a system during chemical reactions.In these reactions different atomic species rearranged themselves into new configuration while conserving the overall inventory of atoms. That is, atoms could change their partners but the total number of identity of the atoms remained invariant.

The quantum speed limit describes the maximum rate at which a quantum system, here the quantized field of the optical cavity, can transition from one state to another. Now, Luis Orozco’s group at JQI, in collaboration with researchers from Shanxi University, China and Los Alamos National Laboratory have studied how fast a photon trapped inside of a cavity settled as they varied its coupling to a reservoir of laser-cooled atoms. The results were published recently in the journal Physical Review Letters, and show that the atomic environment could provide a speed-up in the time it took for the system to reach equilibrium.

If you could peek at the inner workings of a computer processor you would see billions of transistors switching back and forth between two states. In optical communications, information from the switches can be encoded onto light, which then travels long distances through glass fiber. Researchers at the Joint Quantum Institute and the Department of Electrical and Computer Engineering are working to harness the quantum nature of light and semiconductors to expand the capabilities of computers in remarkable ways.

The Joint Quantum Institute would like to again congratulate the 2012 Nobel Prize in physics recipients, David Wineland and Serge Haroche. The Nobel Prize committee cites Wineland and Haroche “for ground-breaking experimental methods that enable measuring and manipulation of individual quantum systems.” The awards were bestowed during the ceremony in Stockholm on December 10, 2012.

Qubit-based computing exploiting spooky quantum effects like entanglement and superposition will speed up factoring and searching calculations far above what can be done with mere zero-or-one bits. To domesticate quantum weirdness, however, to make it a fit companion for mass-market electronic technology, many tricky bi-lateral and multi-lateral arrangements---among photons, electrons, circuits, cavities, etc.---need to be negotiated.