Monday, April 16, 2012

Last week papers (16th week 2012)

Now, Happy belated easter; writing in advance is really confusing because today is the first week of Easter and this will not see light until the second... and I'm rambling... back to business, the interesting things on the physics 'tubes from April 9th to 15th...

Published
  • "Tavis-Cummings model beyond the rotating wave approximation: Quasidegenerate qubits" by S. Agarwal, S.M. Hashemi Rafsanjani and J. H. Eberly , Physical Review A 85,  043815 (2012).

    As Rabi model has come back, it was not long before the many two-level system version should appear back in press. Here the dynamics in a particular regime where the energy gap of the two-level system  is way smaller than the frequency of the field is explored with strong coupling via an adiabatic approximation known for the same regime but for a single two-level system interacting with a field.
Preprints
  • "Can free will emerge from determinism in quantum theory?" by G. Brassard and P. Raymond-Robichaud et. al., arXiv: 1204.2128v1 [quant-ph].

    They push a deterministic, local and realistic interpretation of quantum mechanics, this never gets old at all and now we have a "parallel lives" added to the zoo of interpretations. If you like interpretations, philosophical speculation and so, this is for you  

  • "Producing and measuring entanglement between two beams of microwave light" by E. Flurin et. al., arXiv: 1204.0732v1 [quant-ph].

    I'm too lazy to read it today but entanglement between beams of microwave is interesting. 

  • "Thermal phase transitions for Dicke-type models in the ultra-strong coupling limit" by M. Aparicio Alcalde et. al., arXiv: 1204.2271v1 [quant-ph].

    I like almost everything related to Dicke model, here a study of thermal phase transitions of the mathematical model is presented. I like papers involving Emary and Brandes, they are nice reads.

Monday, April 9, 2012

Last week papers (15th week 2012)...


I told you about the Nature Physics Insight on Quantum Simulation, so I will skip those 

Published
  • "Ultra-high Q mechanical oscillators through optical trapping" by  D. E. Chang,  et. al., New Journal of Physics 14, 045002(2012).

    This is interesting: Reaching the quantum ground state of a mechanical oscillator at room temperature.The authors propose the use of optical forces to free a the characteristics of a mechanical structure from its material properties.
      
  • "Widely Tunable, Nondegenerate Three-Wave Mixing Microwave Device Operating
    near the Quantum Limit" by N. Roch et. al., Physical Review Letters 108, 147701 (2012).

    Now, the best for the last. I find this awesome, people are making better and better microwave resonators, emitters and now it is possible to do three-wave mixing in the microwave regime!

Preprints
  • "Entanglement control in hybrid optomechanical systems" by B. Rogers et. al., arXiv: 1204.0780v1 [quant-ph].

    I'm too lazy to read it today but seems quite interesting...  

  • "Producing and measuring entanglement between two beams of microwave light" by E. Flurin et. al., arXiv: 1204.0732v1 [quant-ph].

    I'm too lazy to read it today but entanglement between beams of microwave is interesting. 

Tuesday, April 3, 2012

Fear...

Fear is an emotion caused by a perceived threat (real or imaginary).

Fear is a kind of survival mechanism, an automatic response that prepares mind and body for the unknown; a really bad unknown. 

Fear, reigned, may lead to acts beyond our idea of human capabilities or, unreigned, to crushing anxiety crippling life at the innermost sanctuary of the mind. 

I had never felt fear living in Mexico. Now I do and I'm not even in my homeland. No more than five years ago, the sight of a random guy walking aimlessly the parking lot during the wee hours just made me think of a dude smoking a cigarette or waiting for his friends to keep the party on; now, it kept me looking through the window for the half hour the dude was there, searching for security's phone in the emergency sheet at the door and wondering where the fuck was the security guard whose snoring bothered me all the nights before that night. 

I never thought I would get to that. I never thought I would stop taking the overnight bus home to visit mom or giving up driving uncountable hours by day or night during vacations. I gave those up no more than five years ago. 

I know what it is to live a normal life with normal fears and that's either in the so far untouched center of Mexico (Puebla and Queretaro seem to be the less conflictive) or far from this beautiful country. Sad but true.

Fuck fear!

Monday, April 2, 2012

It's Quantum Simulation issue in Nature Physics Insight!

I can tell you that this is one of  Feynman's most beautiful phrase and I use it as often as possible in my presentations as opening slide:

 “Nature isn't classical, dammit, and if you want to make a simulation of nature, you'd better make it quantum mechanical, and by golly it's a wonderful problem, because it doesn't look so easy.”
That's the opening phrase for Trabesinger's editorial on the current issue of Nature Physics that includes a commentary by Cirac and Zoleer and reviews by Bloch, Dalibard & Nascimbéne, Blatt & Ross, Aspuru-Guzik & Walther, and Houck, Tureci and Koch.

Enjoy! I know I will...

Last Week Papers (14th week 2012)

It feels good to be back in an office and able to follow the literature. I'm thinking that I like the list format and now will split it in two: published and pre-prints because it is good to talk about pre-prints.

Published

  • "Quantum Interface between an Electrical Circuit and a Single Atom" by  D. Kielpinski,  et. al., Physical Review Letters 108, 130504 (2012)

    They have shown it may be possible to couple an ion to a quantized current from a superconducting circuit. That's nice as the experiments in classical coupling of currents and ions can be used to build upon them and get to this. Interesting read.
  • "Optical Detection of the Quantization of Collective Atomic Motion" by N. Brahams et. al., Physical Review Letters 108, 133601 (2012).

    They are measuring the collective motion of a gas coupled to a cavity field. That impresses me.

  • "Superradiance in spin- j particles: Effects of multiple levels" by G._D Lin and S. F. Yelin, Physical Review A 85, 033831 (2012).

    It has always been a problem to talk about superradiance in two-level systems. Physically sound models with two-level systems involve Raman pumping to auxiliary levels in 4-levels schemes. It has always been mentioned that it may be possible to have superradiance with multi-level atoms. Well, they calculate it and show the effect of multi-level atoms in radiance, decay and so on...

  • " A heuristic approach to BEC self-trapping  in double wells beyond the mean field" by K. Rapedius,  Journal of Physics B: Atomic, Molecular and Optical Physics 45, 085303 (2012).

  • A semi-classical analysis of the Bose-Hubbard dimer Hamiltonian with some curious variations that seem to help producing some approximations that may be valid in the mean-field and finite particle number cases.
      
  • "Effects of orbital angular momentum on the geometric spin Hall effect of light" by L.-J. Kong, Physical Review Letters 85, 035804(2012).

    Reading it and trying to figure it out... I have never read about the spin Hall effect of light and it seems like there are two different kinds: one at a gradient refractive index interface and another that is geometric and relates to observation from a frame tilted with respect to the propagation direction. I need to read more about all this things.

Preprints
  • "Exact real-time dynamics of the quantum Rabi model" by F.A. Wolf, M. Kollar, and D. Braak, arXiv: 1203.6039v1 [quant-ph].

    Last year Braak wrote a very nice PRL where he presented the proper system of Rabi model; now, this follow-up paper builds upon the basis presented before and analyses the dynamical behavior in different time regimes. I wonder why nobody cites E. A. Tur's papers on approximations to the eigenvalues of Rabi model. Anyway,  This manuscript is quite interesting and a must read if you work in Quantum Optics.  

  • "Quantum thermometry using the ac Stark shift within the Rabi model" by K.D.B. Higgins, B.W. Lovett, and E.M. Gauger, arXiv: 1203.5994v1 [quant-ph].

    I have the feeling that whenever I get to grasp what they are doing I'm gonna like it.