Last week papers (17th week of 2012)

Without further ado...

Published

• "Quantum phase transition in the Dicke model with critical and noncritical entanglement" by  L. Bakemeier, A. Alvermann and H. Fehske, Physical Review A 85, 043821 (2012).
  
  
  A phase transition analysis on the Dicke model exploring the behavior of the system when the frequency of the field mode tends to zero, called the classical oscillator limit by the authors, where the model goes to a Lipkin-Meshkov-Glick model. Why people don't cite us? Really... 

• "Ultimate limits to quantum metrology and the meaning of the Heisenberg limit" by M. Zwierz, C.A. Perez-Delgado and Pieter Kok, Physical Review A 85,  042112 (2012).
  
  
  I remember being at a seminar where Carlos presented this work in CQT. It's a mashup of query complexity with quantum mechanics to reformulate a Heisenberg limit for quantum metrology based on the idea of physical resources. 

• "Ginzburg-Landau theory for the Jaynes-Cummings-Hubbard model" by Christian Nietner and Axel Pelster, Physical Review A 85,  043831 (2012).
  
  
  As  you know, I like anything Jaynes-Cummings or Dicke. A while ago some people decided to study what happens when you couple cQED building blocks (cavities with an atom inside) and used a polaritonic approach to the problem to describe an isulator and superfluid phase of the system. So, it is nice that a phenomenological theory of superconductivity is used to describe the superfluid phase of the system! 

Preprints

• "Non-Markovian quantum dynamics and classical chaos" by I. Garcia-Mata, C. Pineda and D. Wisniacki, arXiv: 1204.3614v1 [quant-ph].
  
  
  The authors study a system coupled to an environment with different levels of chaos and analyse how well a chaotic environment models Markovian evolution.


• "Theory of optomechanics: Oscillator- eld model of moving mirrors" by C.R. Galley, R.O. Benhunin and B.L. Hu, arXiv: 1204.2569v1 [quant-ph].
  
  
  A nice theory of coupling between a field and a moving mirror from first principles that converges to models used in the literature. I was more interested in the convergence to what they called the N x coupling that we widely use in Quantum Optics.


• "Superradiant quantum phase transition in a circuit QED system: a revisit from a fully microscopic point of view" by D.Z. Xu, Y.B. Gao and C.P. Sun, arXiv: 1204.2602v1 [quant-ph].
  
  
  The authors derive the Dicke Hamiltonian from a microscopic model circuit-QED involving superconducting qubits and a quantized field. These model allows for a so-called superradiant phase transition in contrast to a previous analysis in the literature.


• "Exact solution to the quantum Rabi model within Bogoliubov operators" by Q.H. Chen, C. Wang and K.L. Wang, arXiv: 1204.3668v1 [quant-ph].
  
  It is a nice step by step demonstration of how to get a exact solution for the quantum Rabi model with an additional tunneling. The authors recover Braak's solution. I personally love the closing paragraph.