ZhETF, Vol. 149,
p. 666 (March 2016)
(English translation - JETP,
Vol. 122, No. 3,
available online at www.springer.com
U(1) and SU(2) quantum dissipative systems: the Caldeira-Leggett versus Ambegaokar-Eckern-Schön approaches
Received: August 4, 2015
There are two paradigmatic frameworks for treating quantum systems coupled to a dissipative environment: the Caldeira-Leggett and Ambegaokar-Eckern-Schön approaches. Here, we recall the differences between them and explain the consequences of applying each to a zero-dimensional spin (having an SU(2) symmetry) in a dissipative environment (a dissipative quantum dot near or beyond the Stoner instability point).