Posted on 04/06/2013 9:37:08 PM PDT by Kevmo
Coherent Oscillations in an Exciton-Polariton Josephson Junction
K. G. Lagoudakis1, B. Pietka1, M. Wouters2, R. André3, B. Deveaud-Plédran1 1ICMP, Ecole Polytechnique Fédérale de Lausanne(EPFL),1015 Lausanne, Switzerland. 2ITP, Ecole Polytechnique Fédérale de Lausanne(EPFL),1015 Lausanne, Switzerland. 3Institut Néel, CNRS, Grenoble, France.
Abstract:
We report on the observation of spontaneous coherent oscillations in a microcavity polariton bosonic Josephson junction. The condensation of exciton polaritons takes place under incoherent excitation in a disordered environment, where double potential wells tend to appear in the disordered landscape. Coherent oscillations set on at an excitation power well above the condensation threshold. The time resolved population and phase dynamics reveal the analogy with the AC Josephson effect. We have introduced a theoretical two-mode model to describe the observed effects, which allows us to explain how the different realizations of the pulsed experiment have a similar phase relation.
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In this work we have provided experimental evidence of coherent oscillations in a Bosonic Josephson junction formed by two exciton polariton condensates created under nonresonant pulsed excitation in a double well geometry. We have shown the simultaneous existence of population and phase oscillations and have carefully evaluated their amplitudes and average values. The saw-tooth like oscillations persist for the whole life time of the condensates and are the polariton analog of the AC Josephson regime. Our theoretical analysis shows that the Josephson oscillations survive the realization averaging linked with the random initial phase, though with reduced amplitude, thanks to a spontaneous synchronization mechanism that only appears above a critical pump intensity. The present realization of the Josephson effect relies on the accidental presence of coupled wells in our disordered microcavity. Controlled growth of polariton traps with mesa structures [18] and micropilars [19] will allow for a more systematic analysis of the different regimes of Josephson oscillations, where polariton-polariton interactions can play a more pronounced role. Also, combining nonresonant with resonant excitation will provide full control over the initial conditions of the Josephson oscillations.
I notice that you offer nothing specific that these oscillations will be used for, can be sustained by, or any practical application thereof.
***If you can’t see that a valid, scientifically testable theory and experimental result can lead to breakthroughs in LENR such that very cheap and towel-head-independent energy is attainable then God Help You.
From 2009
Nonequilibrium Josephson oscillations in Bose-Einstein condensates without dissipation
work done at Cornell
And of course the work from 2012
Macroscopic quantum self-trapping and Josephson oscillations of exciton-polaritons
M. Abbarchi, A. Amo, V. G. Sala, D. D. Solnyshkov, H. Flayac, L. Ferrier, I. Sagnes, E. Galopin, A. Lemaitre, G. Malpuech, J. Bloch
(Submitted on 21 Dec 2012)
A textbook example of quantum mechanical effects is the coupling of two states through a tunnel barrier. In the case of macroscopic quantum states subject to interactions, the tunnel coupling gives rise to Josephson phenomena including Rabi oscillations, the a.c. and d.c. effects, or macroscopic self-trapping depending on whether tunnelling or interactions dominate. Non-linear Josephson physics, observed in superfluid helium and atomic condensates, has remained inaccessible in photonic systems due to the required effective photon-photon interactions. We report on the observation of non-linear Josephson oscillations of two coupled polariton condensates confined in a photonic molecule etched in a semiconductor microcavity. By varying both the distance between the micropillars forming the molecule and the condensate density in each micropillar, we control the ratio of coupling to interaction energy. At low densities we observe coherent oscillations of particles tunnelling between the two micropillars. At high densities, interactions quench the transfer of particles inducing the macroscopic self-trapping of the condensate in one of the micropillars. The finite lifetime of polaritons results in a dynamical transition from self-trapping to oscillations with pi phase. Our results open the way to the experimental study of highly non-linear regimes in photonic systems, such as chaos or symmetry-breaking bifurcations
Learn some physics will you?
Learn some physics will you?
***I got an A in Calculus-based Nuclear Physics in College for the engineering curriculum. What grade did you get?
Thanks 4 Bumping The Thread T4BTT
http://www.freerepublic.com/focus/chat/2965392/posts?page=19#19
Before tunneling happens, and after tunneling happens, the mass, momentum, energy, etc., are all the same. That is necessary and sufficient to say that no conservation laws were violated. Wondering how the tunneling happened is like wondering how the photon knows which slit to go through, in the double slit experiment. It’s meaningless, unless you set up a different experiment to detect that - in which case your double slit diffraction pattern vanishes. It is easy to imagine that tunneling happens as a result of energy borrowed from vacuum fluctuations. But that energy is given back, so everything is still conserved.
what the heck is ‘calculus based nuclear physics’? All the engineering students I know took standard physics that the physicists took....but then maybe you went to some other kind of university. My grades in all four years of physics were A.
These oscillations are part of superconductor research you bozo ( and no that is not a cousin of the Boson). The research has been ongoing for quite some time now.....most of the early trapping was done by laser induced Raman shifting. This is neither new nor specifically exciting and is small scale stuff that is proving the theories of quantum mechanics.....which along with quantum electrodynamics are very interesting courses within most physics departments.
what the heck is ‘calculus based nuclear physics’?
***Do you have some sort of comprehension problem? It’s the class an engineer takes after a year & a half of calculus based physics. Obviously, if you took 4 years of physics then you took that class. What exactly is your freeping problem?
All the engineering students I know took standard physics that the physicists took....but then maybe you went to some other kind of university.
***Yes, engineers typically take about a year & half of calculus based physics, and then go on to engineering courses, not necessarily “some other kind of university”. Learn some communication skills, won’t you?
My grades in all four years of physics were A.
***Is that your requirement for a freeper to engage in interesting scientific discussion on physics? If so, that makes you an elitist.
These oscillations are part of superconductor research you bozo
***They are also applicable to current LENR theories, you bozo.
( and no that is not a cousin of the Boson).
The research has been ongoing for quite some time now.....most of the early trapping was done by laser induced Raman shifting. This is neither new nor specifically exciting and is small scale stuff that is proving the theories of quantum mechanics.....which along with quantum electrodynamics are very interesting courses within most physics departments.
***You’re behind the curve. I suggest you start reading Vortex-L postings and start interacting with the scientists there. That is, unless your requirement is that everyone have a 4 year physics degree.
These oscillations are part of superconductor research you bozo
***Thanks 4 Bumping The Thread T4BTT
http://www.freerepublic.com/focus/chat/2965392/posts?page=19#19
Aren't the cold fusion kooks allowed to coopt the legitimacy of superconductor research as their own?
How so?
I suggest you start reading Vortex-L postings and start interacting with the scientists there.
I see, you can't defend it yourself, so you refer people off to the mailing list. You should keep this nonsense off of FR and stay on the mailing list where you belong.
His requirement seems to be to have a 4 year physics college degree. Do you have one? Is that the current elitist Luddite anti-LENR skeptopath requirement in order to discuss physics on FR?
Thanks 4 Bumping The Thread T4BTT
http://www.freerepublic.com/focus/chat/2965392/posts?page=19#19
Look at the way you discuss physics. That belongs on Vortex, a mailing list specifically for kooks, not FR.
Lurkers will note that Dr. Brian Josephson received the Nobel Prize in which the Josephson Junction is named. Here’s what he has to say about LENR:
www.youtube.com/watch?v=G8eIhth8Iw8
“what isn’t conserved in tunneling?” Hmmmm...positronic pay stations and orbital off ramps.
He was brilliant 50 years ago. Today he's more of an elderly kook. Once again, you're trying to co-opt someone else's legitimacy for your three ring circus.
well when you put it that way....of course they can because nothing else seems to be working
I find it interesting that you are the only one who has a comprehension problem. The oh so important physics class you took, it is a beginning class. You took an introductory physics class as either a freshman or sophomore. Whoop dee foo. You fail to mention what type of ‘engineering’ you do or are qualified to do.
When you have passed something that looks like an upper division quantum mechanics class then I will consider your input.
By the way....do you even know what a Josephson junction is? Can you tell me the nonlinear photonic response seen in both the ac and dc oscillations produced in the studies you cited? Yeah that’s what I thought.
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