Efficient finitetime measurements under thermal regimes
Abstract
Contrary to conventional quantum mechanics, which treats measurement as instantaneous, here we explore a model for finitetime measurement. The main twolevel system interacts with the measurement apparatus in a Markovian way described by the Lindblad equation, and with an environment, which does not include the measuring apparatus. To analyse the environmental effects on the final density operator, we use the Redfield approach, allowing us to consider a nonMarkovian noise. In the present hybrid theory, to trace out the environmental degrees of freedom, we use a previously developed analytic method based on superoperator algebra and NakajimaZwanzig superoperators. Here, we analyse two types of systemenvironment interaction, phase and amplitude damping, which allows us to conclude that, in general, a finitetime quantum measurement performed during a certain period is more efficient than an instantaneous measurement performed at the end of it, because the rate of change of the populations is attenuated by the systemmeasurement apparatus interaction.
 Publication:

European Physical Journal Plus
 Pub Date:
 October 2014
 DOI:
 10.1140/epjp/i2014142060
 Bibcode:
 2014EPJP..129..206B