Bulletin of the American Physical Society
APS March Meeting 2013
Volume 58, Number 1
Monday–Friday, March 18–22, 2013; Baltimore, Maryland
Session U4: Invited Session: Quantum Reservoir Engineering and Feedback
11:15 AM–2:15 PM,
Thursday, March 21, 2013
Room: Ballroom IV
Sponsoring Units: DCMP GQI
Chair: Steven Girvin, Yale University
Abstract ID: BAPS.2013.MAR.U4.2
Abstract: U4.00002 : Quantum measurement in action*
11:51 AM–12:27 PM
Preview Abstract Abstract
(Applied Physics, Yale University)
A quantum system subject to the infinitely-strong measurement of textbook physics undergoes a discontinuous, random state collapse. However, in practice, measurements often involve a finite-strength, continuous process whose iteration leads to a projective evolution only asymptotically. Moreover, if the observation apparatus is fully efficient informationally, the measured system can remain at all times in a pure state. The stochastic evolution of this pure state is trackable from the measurement record. Thus, an initial superposition of states can be usefully transformed by a partial measurement rather than be entirely destroyed. This striking property has been demonstrated in superconducting qubit experiments in which readout is performed by a microwave signal sent through a cavity dispersively coupled to the qubit, and thereafter processed by an amplifier operating at the quantum limit. Such accurate monitoring of a qubit state is an essential prerequisite for measurement-based feedback control of quantum systems.
*Work supported by: IARPA, ARO and NSF.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2013.MAR.U4.2
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