Skip to main content

Home/ Advanced Concepts Team/ Group items tagged light-matter

Rss Feed Group items tagged

Filter: All | Bookmarks | Topics Simple Middle
jmlloren

Scientists discover how to turn light into matter after 80-year quest - 5 views

phys.org/...-05-scientists-year-quest.html

PHY MAD

shared by jmlloren on 19 May 14 - No Cached
  • Thijs Versloot on 19 May 14
     
    Theoretized 80 years ago was Breit-Wheeler pair production in which two photons result in an electron-positron pair (via a virtual electron). It is a relatively simple Feynmann diagram, but the problem is/was how to produce in practice a high energy photon-photon collider... The collider experiment that the scientists have proposed involves two key steps. First, the scientists would use an extremely powerful high-intensity laser to speed up electrons to just below the speed of light. They would then fire these electrons into a slab of gold to create a beam of photons a billion times more energetic than visible light. The next stage of the experiment involves a tiny gold can called a hohlraum (German for 'empty room'). Scientists would fire a high-energy laser at the inner surface of this gold can, to create a thermal radiation field, generating light similar to the light emitted by stars. They would then direct the photon beam from the first stage of the experiment through the centre of the can, causing the photons from the two sources to collide and form electrons and positrons. It would then be possible to detect the formation of the electrons and positrons when they exited the can. Now this is a good experiment... :)
  • ...6 more comments...
  • jmlloren on 19 May 14
     
    The solution of thrusting in space.
  • dejanpetkow on 20 May 14
     
    Thrusting in space is solved already. Maybe you wanted to say something different?
  • Thijs Versloot on 21 May 14
     
    Thrusting until your fuel runs out is solved, in this way one can produce mass from, among others, solar/star energy directly. What I like about this experiment is that we have the technology already to do it, many parts have been designed for inertial confinement fusion.
  • johannessimon81 on 29 May 14
     
    I am quite certain that it would be more efficient to use the photons directly for thrust instead of converting them into matter. Also, I am a bit puzzled at the asymmetric layout for photon creation. Typically, colliders use two beam of particle with equal but opposite momentum. Because the total momentum for two colliding particles is zero the reaction products are produced more efficiently as a minimum of collision energy is waisted on accelerating the products. I guess in this case the thermal radiation in the cavity is chosen instead of an opposing gamma ray beam to increase the photon density and increase the number of collisions (even if the efficiency decreases because of the asymmetry). However, a danger from using a high temperature cavity might be that a lot of thermionic emission creates lots of free electrons with the cavity. This could reduce the positron yield through recombination and would allow the high energetic photons to loose energy through Compton scattering instead of the Breit-Wheeler pair production.
  • Thijs Versloot on 30 May 14
     
    Well, the main benefit from e-p pair creation might be that one can accelerate these subsequently to higher energies again. I think the photon-photon cross-section is extremely low, such that direct beam-beam interactions are basically not happening (below 1/20.. so basically 0 according to quantum probability :P), in this way, the central line of the hohlraum actually has a very high photon density and if timed correctly maximizes the reaction yield such that it could be measured.
  • johannessimon81 on 30 May 14
     
    I agree about the reason for the hohlraum - but I also keep my reservations about the drawbacks. About the pair production as fuel: I pretty sure that your energy would be used smarter in using photon (not necessarily high energy photons) for thrust directly instead of putting tons of energy in creating a rest-mass and then accelerating that. If you look at E² = (p c)²+(m0 c)² then putting energy into the mass term will always reduce your maximum value of p.
  • Thijs Versloot on 31 May 14
     
    True, but isnt it E2=(pc)^2 + (m0c^2)^2 such that for photons E\propto{pc} and for mass E\propto{mc^2}. I agree it will take a lot of energy, but this assumes that that wont be the problem at least. The question therefore is whether the mass flow of the photon rocket (fuel consumed to create photons, eg fission/fusion) is higher/lower than the mass flow for e-p creation. You are probably right that the low e-p cross-section will favour direct use of photons to create low thrust for long periods of time, but with significant power available the ISP might be higher for e-p pair creation.
  • johannessimon81 on 03 Jun 14
     
    In essence the equation tells you that for photons with zero rest mass m0 all the energy will be converted to momentum of the particles. If you want to accelerate e-p then you first spend part of the energy on creating them (~511 keV each) and you can only use the remaining energy to accelerate them. In this case the equation gives you a lower particle momentum which leads to lower thrust (even when assuming 100% acceleration efficiency). ISP is a tricky concept in this case because there are different definitions which clash in the relativistic context (due to the concept of mass flow). R. Tinder gets to a I_SP = c (speed of light) for a photon rocket (using the relativistic mass of the photons) which is the maximum possible relativistic I_SP: http://goo.gl/Zz5gyC .
jmlloren

Exotic matter : Insight : Nature - 5 views

www.nature.com/...index.html

nan phy

shared by jmlloren on 03 Aug 10 - Cached
LeopoldS liked it
  • jmlloren on 03 Aug 10
     
    Trends in materials and condensed matter. Check out the topological insulators. amazing field.
  • ...12 more comments...
  • Luzi Bergamin on 03 Aug 10
     
    Aparently very interesting, will it survive the short hype? Relevant work describing mirror charges of topological insulators and the classical boundary conditions were done by Ismo and Ari. But the two communities don't know each other and so they are never cited. Also a way to produce new things...
  • jmlloren on 04 Aug 10
     
    Thanks for noticing! Indeed, I had no idea that Ari (don't know Ismo) was involved in the field. Was it before Kane's proposal or more recently? What I mostly like is that semiconductors are good candidates for 3D TI, however I got lost in the quantum field jargon. Yesterday, I got a headache trying to follow the Majorana fermions, the merons, skyrnions, axions, and so on. Luzi, are all these things familiar to you?
  • Luzi Bergamin on 04 Aug 10
     
    Ismo Lindell described in the early 90's the mirror charge of what is now called topological insulator. He says that similar results were obtained already at the beginning of the 20th century... Ismo Lindell and Ari Sihvola in the recent years discussed engineering aspects of PEMCs (perfect electro-megnetic conductors,) which are more or less classical analogues of topological insulators. Fundamental aspects of PEMCs are well knwon in high-energy physics for a long time, recent works are mainly due to Friedrich Hehl and Yuri Obukhov. All these works are purely classical, so there is no charge quantisation, no considerations of electron spin etc. About Majorana fermions: yes, I spent several years of research on that topic. Axions: a topological state, of course, trivial :-) Also merons and skyrnions are topological states, but I'm less familiar with them.
  • LeopoldS on 04 Aug 10
     
    "Non-Abelian systems1, 2 contain composite particles that are neither fermions nor bosons and have a quantum statistics that is far richer than that offered by the fermion-boson dichotomy. The presence of such quasiparticles manifests itself in two remarkable ways. First, it leads to a degeneracy of the ground state that is not based on simple symmetry considerations and is robust against perturbations and interactions with the environment. Second, an interchange of two quasiparticles does not merely multiply the wavefunction by a sign, as is the case for fermions and bosons. Rather, it takes the system from one ground state to another. If a series of interchanges is made, the final state of the system will depend on the order in which these interchanges are being carried out, in sharp contrast to what happens when similar operations are performed on identical fermions or bosons." wow, this paper by Stern reads really weired ... any of you ever looked into this?
  • jmlloren on 04 Aug 10
     
    C'mon Leopold, it's as trivial as the topological states, AKA axions! Regarding the question, not me!
  • LeopoldS on 04 Aug 10
     
    just looked up the wikipedia entry on axions .... at least they have some creativity in names giving: "In supersymmetric theories the axion has both a scalar and a fermionic superpartner. The fermionic superpartner of the axion is called the axino, the scalar superpartner is called the saxion. In some models, the saxion is the dilaton. They are all bundled up in a chiral superfield. The axino has been predicted to be the lightest supersymmetric particle in such a model.[24] In part due to this property, it is considered a candidate for the composition of dark matter.[25]"
  • jmlloren on 04 Aug 10
     
    Thank's Leopold. Sorry Luzi for being ironic concerning the triviality of the axions. Now, Leo confirmed me that indeed is a trivial matter. I have problems with models where EVERYTHING is involved.
  • Luzi Bergamin on 04 Aug 10
     
    Well, that's the theory of everything, isn't it?? Seriously: I don't think that theoretically there is a lot of new stuff here. Topological aspects of (non-Abelian) theories became extremely popular in the context of string theory. The reason is very simple: topological theories are much simpler than "normal" and since string theory anyway is far too complicated to be solved, people just consider purely topological theories, then claiming that this has something to do with the real world, which of course is plainly wrong. So what I think is new about these topological insulators are the claims that one can actually fabricate a material which more or less accurately mimics a topological theory and that these materials are of practical use. Still, they are a little bit the poor man's version of the topological theories fundamental physicists like to look at since electrdynamics is an Abelian theory.
  • jmlloren on 04 Aug 10
     
    I have the feeling, not the knowledge, that you are right. However, I think that the implications of this light quantum field effects are great. The fact of being able to sustain two currents polarized in spin is a technological breakthrough.
  • LeopoldS on 04 Aug 10
     
    not sure how much I can contribute to your apparently educated debate here but if I remember well from my work for the master, these non-Abelian theories were all but "simple" as Luzi puts it ... and from a different perspective: to me the whole thing of being able to describe such non-Abelian systems nicely indicates that they should in one way or another also have some appearance in Nature (would be very surprised if not) - though this is of course no argument that makes string theory any better or closer to what Luzi called reality ....
  • Luzi Bergamin on 04 Aug 10
     
    Well, electrodynamics remains an Abelian theory. From the theoretical point of view this is less interesting than non-Abelian ones, since in 4D the fibre bundle of a U(1) theory is trivial (great buzz words, eh!) But in topological insulators the point of view is slightly different since one always has the insulator (topological theory), its surrounding (propagating theory) and most importantly the interface between the two. This is a new situation that people from field and string theory were not really interested in.
  • Dario Izzo on 04 Aug 10
     
    guys... how would you explain this to your gran mothers?
  • jmlloren on 05 Aug 10
  • LeopoldS on 07 Aug 10
     
    *you* tried *your* best .... ??
jcunha

The physics of life - 2 views

www.nature.com/...the-physics-of-life-1.19105

science BIO PHY

shared by jcunha on 07 Jan 16 - No Cached
LeopoldS liked it
  • jcunha on 07 Jan 16
     
    Research in active-matter systems is a growing field in biology. It consists in using theoretical statistical physics in living systems such as molecule colonies to deduce macroscopic properties. The aim and hope is to understand how cells divide, take shape and move on these systems. Being a crossing field between physics and biology "The pot of gold is at the interface but you have to push both fields to their limits." one can read
  • LeopoldS on 17 Jan 16
     
    Maybe we should discuss about this active matter one of these days? "These are the hallmarks of systems that physicists call active matter, which have become a major subject of research in the past few years. Examples abound in the natural world - among them the leaderless but coherent flocking of birds and the flowing, structure-forming cytoskeletons of cells. They are increasingly being made in the laboratory: investigators have synthesized active matter using both biological building blocks such as microtubules, and synthetic components including micrometre-scale, light-sensitive plastic 'swimmers' that form structures when someone turns on a lamp. Production of peer-reviewed papers with 'active matter' in the title or abstract has increased from less than 10 per year a decade ago to almost 70 last year, and several international workshops have been held on the topic in the past year."
santecarloni

Three new maps shine light on dark matter - physicsworld.com - 0 views

physicsworld.com/...48273

dark matter Space PHY

shared by santecarloni on 13 Jan 12 - No Cached
  • santecarloni on 13 Jan 12
     
    Three independent teams of astronomers have released new and improved maps of where dark matter is lurking in parts of the universe
ESA ACT

A solid-state light-matter interface at the single-photon level - 0 views

www.nature.com/...nature07607.html

PHY NAN technology communications

shared by ESA ACT on 24 Apr 09 - Cached
  • ESA ACT on 24 Apr 09
     
    First demostration of coherent and reversible mapping of a light field with less than one photon per pulse onto an ensemble of approx10^7 atoms naturally trapped in a solid.
Thijs Versloot

Scientists have developed a material so dark that you can't see it... - 7 views

www.independent.co.uk/...t-you-cant-see-it-9602504.html

technology material light absorption

shared by Thijs Versloot on 14 Jul 14 - No Cached
  • Thijs Versloot on 14 Jul 14
     
    A British company has produced a "strange, alien" material so black that it absorbs all but 0.035 per cent of visual light, setting a new world record. To stare at the "super black" coating made of carbon nanotubes - each 10,000 times thinner than a human hair - is an odd experience.
  • Marcus Maertens on 15 Jul 14
     
    Finally! Nowadays blacks were always too bright for my taste...
  • Ma Ru on 19 Jul 14
     
    "No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it." I will keep waiting for my darkness-emitting diodes...
Thijs Versloot

Lasers May Solve the Black Hole Information Paradox - 0 views

iopscience.iop.org/...075015

black hole

shared by Thijs Versloot on 26 Mar 14 - No Cached
  • Thijs Versloot on 26 Mar 14
     
    "In an effort to help solve the black hole information paradox that has immersed theoretical physics in an ocean of soul searching for the past two years, two researchers have thrown their hats into the ring with a novel solution: Lasers. Technically, we're not talking about the little flashy devices you use to keep your cat entertained, we're talking about the underlying physics that produces laser light and applying it to information that falls into a black hole. According to the researchers, who published a paper earlier this month to the journal Classical and Quantum Gravity (abstract), the secret to sidestepping the black hole information paradox (and, by extension, the 'firewall' hypothesis that was recently argued against by Stephen Hawking) lies in stimulated emission of radiation (the underlying physics that generates laser light) at the event horizon that is distinct from Hawking radiation, but preserves information as matter falls into a black hole."
johannessimon81

Cosmological model without accelerated expansion proposed - 1 views

www.nature.com/...e-may-not-be-expanding-1.13379

science cosmology

shared by johannessimon81 on 07 Aug 13 - No Cached
  • johannessimon81 on 07 Aug 13
     
    Redshift in this model is partially produced by a change in the masses of elementary particles (and atoms)
  • ...3 more comments...
  • Thijs Versloot on 25 Aug 13
     
    It seems to solve the problem of infinite energy density at the singularity in any case. I would love to see a way of experimentally verifying this, although most people seem to believe it is wrong. I read the following quote though by Dirac to Pauli "we all agree your idea is crazy, but the real question is it crazy enough to be correct?"
  • H H on 25 Aug 13
     
    As far as I can see, this is not untestable per se, rather an explanation to the redshift that is equivalent to accelerating expansion. It is not that the theory is untestable, rather just another way of looking at it. Kind of like that its sometimes convenient to consider light a particle, sometimes a wave. In the same way it could sometime convenient to view the universe as static with increasing mass instead.
  • Thijs Versloot on 26 Aug 13
     
    Well the premiss "matter getting heavier" may be up to falsification in some way or another. Currently, there is no absolute method to determine mass so it might even be plausible that this is actually the case. I don't think it is related but there is a problem with the 1kg-standards (1 official and 6 copies) where the masses seem to deviate.
  • johannessimon81 on 26 Aug 13
     
    It should not be impossible to verify a change in mass(es) over time. For example the electron cyclotron frequency scales ~e/m while the Hydrogen emission frequencies scale with ~m*e^4. Using multiple relationships like that which can be easily and accurately measured an increase in the mass of fundamental particles should - in principle - be detectable (even if the mass of the earth increases at the same time changing the relativistic reference frame).
  • Thijs Versloot on 26 Aug 13
     
    The Watt balance and a definition using the Planck's constant seems to do the trick and is currently being discussed. Would the electron charge not be problematic as it is related to Coulombs which depends on Amperes which is defined by Newtons which hence depends back on the mass again?
Thijs Versloot

New theory to lead to radiationless revolution - 3 views

www.anu.edu.au/...ad-to-radiationless-revolution

technology science

shared by Thijs Versloot on 01 Sep 15 - No Cached
  • Thijs Versloot on 01 Sep 15
     
    Physicists have found a radical new way to confine electromagnetic energy without it leaking away, akin to throwing a pebble into a pond with no splash. The theory could have broad ranging applications from explaining dark matter to combating energy losses in future technologies.
  • johannessimon81 on 01 Sep 15
     
    I think (but am not sure) that is related to a topic that Dirk Bouwmeester's group at Leiden University works on for a while now: "Linked and knotted beams of light" http://irvinelab.uchicago.edu/papers/nphys1056.pdf
pacome delva

RHIC nets strange antimatter - 0 views

physicsworld.com/...41917

strange_antimatter collider

shared by pacome delva on 08 Mar 10 - Cached
  • The antihypertriton – consisting of an antiproton, an antineutron and an antilambda particle – is the heaviest antinucleus yet produced and opens up a new realm of strange antinucluei. It could also shed light on a number of problems in astrophysics and cosmology, including the dominance of matter over antimatter in the universe.
Francesco Biscani

STLport: An Interview with A. Stepanov - 2 views

www.stlport.org/...StepanovUSA.html

computer science

shared by Francesco Biscani on 23 Mar 10 - Cached
  • Generic programming is a programming method that is based in finding the most abstract representations of efficient algorithms.
  • I spent several months programming in Java.
  • for the first time in my life programming in a new language did not bring me new insights
  • ...2 more annotations...
  • it has no intellectual value whatsoever
  • Java is clearly an example of a money oriented programming (MOP).
  • Francesco Biscani on 23 Mar 10
     
    One of the authors of the STL (C++'s Standard Template Library) explains generic programming and slams Java.
  • ...6 more comments...
  • Ma Ru on 24 Mar 10
     
    "Java is clearly an example of a money oriented programming (MOP)." Exactly. And for the industry it's the money that matters. Whatever mathematicians think about it.
  • Joris _ on 24 Mar 10
     
    It is actually a good thing that it is "MOP" (even though I do not agree with this term): that is what makes it inter-operable, light and easy to learn. There is no point in writing fancy codes, if it does not bring anything to the end-user, but only for geeks to discuss incomprehensible things in forums. Anyway, I am pretty sure we can find a Java guy slamming C++ ;)
  • Francesco Biscani on 24 Mar 10
     
    Personally, I never understood what the point of Java is, given that: 1) I do not know of any developer (maybe Marek?) that uses it for intellectual pleasure/curiosity/fun whatever, given the possibility of choice - this to me speaks loudly on the objective qualities of the language more than any industrial-corporate marketing bullshit (for the record, I argue that Python is more interoperable, lighter and easier to learn than Java - which is why, e.g., Google is using it heavily); 2) I have used a software developed in Java maybe a total of 5 times on any computer/laptop I owned over 15 years. I cannot name of one single Java project that I find necessary or even useful; for my usage of computers, Java could disappear overnight without even noticing. Then of course one can argue as much as one wants about the "industry choosing Java", to which I would counterargue with examples of industry doing stupid things and making absurd choices. But I suppose it would be a kind of pointless discussion, so I'll just stop here :)
  • Joris _ on 24 Mar 10
     
    "At Google, python is one of the 3 "official languages" alongside with C++ and Java". Java runs everywhere (the byte code itself) that is I think the only reason it became famous. Python, I guess, is more heavy if it were to run on your web browser! I think every language has its pros and cons, but I agree Java is not the answer to everything... Java is used in MATLAB, some web applications, mobile phones apps, ... I would be a bit in trouble if it were to disappear today :(
  • Dario Izzo on 24 Mar 10
     
    I personally do not believe in interoperability :)
  • Ma Ru on 24 Mar 10
     
    Well, I bet you'd notice an overnight disappearance of java, because half of the internet would vanish... J2EE technologies are just omnipresent there... I'd rather not even *think* about developing a web application/webservice/web-whatever in standard C++... is it actually possible?? Perhaps with some weird Microsoft solutions... I bet your bank online services are written in Java. Certainly not in PHP+MySQL :) Industry has chosen Java not because of industrial-corporate marketing bullshit, but because of economics... it enables you develop robustly, reliably, error-prone, modular, well integrated etc... software. And the costs? Well, using java technologies you can set-up enterprise-quality web application servers, get a fully featured development environment (which is better than ANY C/C++/whatever development environment I've EVER seen) at the cost of exactly 0 (zero!) USD/GBP/EUR... Since many years now, the central issue in software development is not implementing algorithms, it's building applications. And that's where Java outperforms many other technologies. The final remark, because I may be mistakenly taken for an apostle of Java or something... I love the idea of generic programming, C++ is my favourite programming language (and I used to read Stroustroup before sleep), at leisure time I write programs in Python... But if I were to start a software development company, then, apart from some very niche applications like computer games, it most probably would use Java as main technology.
  • Francesco Biscani on 24 Mar 10
     
    "I'd rather not even *think* about developing a web application/webservice/web-whatever in standard C++... is it actually possible?? Perhaps with some weird Microsoft solutions... I bet your bank online services are written in Java. Certainly not in PHP+MySQL :)" Doing in C++ would be awesomely crazy, I agree :) But as I see it there are lots of huge websites that operate on PHP, see for instance Facebook. For the banks and the enterprise market, as a general rule I tend to take with a grain of salt whatever spin comes out from them; in the end behind every corporate IT decision there is a little smurf just trying to survive and have the back covered :) As they used to say in the old times, "No one ever got fired for buying IBM". "Industry has chosen Java not because of industrial-corporate marketing bullshit, but because of economics... it enables you develop robustly, reliably, error-prone, modular, well integrated etc... software. And the costs? Well, using java technologies you can set-up enterprise-quality web application servers, get a fully featured development environment (which is better than ANY C/C++/whatever development environment I've EVER seen) at the cost of exactly 0 (zero!) USD/GBP/EUR... Since many years now, the central issue in software development is not implementing algorithms, it's building applications. And that's where Java outperforms many other technologies." Apart from the IDE considerations (on which I cannot comment, since I'm not a IDE user myself), I do not see how Java beats the competition in this regard (again, Python and the huge software ecosystem surrounding it). My impression is that Java's success is mostly due to Sun pushing it like there is no tomorrow and bundling it with their hardware business.
  • Joris _ on 24 Mar 10
     
    OK, I think there is a bit of everything, wrong and right, but you have to acknowledge that Python is not always the simplest. For info, Facebook uses Java (if you upload picture for instance), and PHP is very limited. So definitely, in company, engineers like you and me select the language, it is not a marketing or political thing. And in the case of fb, they come up with the conclusion that PHP, and Java don't do everything but complement each other. As you say Python as many things around, but it might be too much for simple applications. Otherwise, I would seriously be interested by a study of how to implement a Python-like system on-board spacecrafts and what are the advantages over mixing C, Ada and Java.
LeopoldS

BBC News - Speed-of-light experiments give baffling result at Cern - 5 views

www.bbc.co.uk/...science-environment-15017484

PHY physics Einstein

shared by LeopoldS on 22 Sep 11 - No Cached
  • LeopoldS on 22 Sep 11
     
    Sante, Luzi have a look at this???!!!
  • ...3 more comments...
  • Luís F. Simões on 23 Sep 11
     
    and here's the xkcd on it: http://xkcd.com/955/
  • Luzi Bergamin on 23 Sep 11
     
    And here's the arXiv paper http://arxiv.org/abs/1109.4897 Serious? Difficult to say. I'm theorist and can't really rate their measurement techniques. Certainly be cautious, mostly such things disappear faster than they appeared.
  • LeopoldS on 23 Sep 11
     
    it took them 3 years to "appear"!
  • Luzi Bergamin on 23 Sep 11
     
    Leo, you mean that they measured 3 years? That's not a point to criticize: since the only interaction of neutrinos with matter is the Weak Interaction (which is indeed very, very weak), it is extremely hard to get a reasonable statistic. By the same reason, it's essentially impossible to shield the experiment from the background. And this background (solar neutrinos, cosmic radiation neutrinos) is huge.
  • pacome delva on 28 Sep 11
     
    for sure a result to be taken seriously. It makes a buzz in my lab... but always be cautious with this kind of declaration, that hugely violates all physics we know and even most of the reasonable alternative theories... Remember the Pionneer anomaly for which it took almost ten years to set up that finally its a thermal effect.
Joris _

Physicists Propose Scheme for Teleporting Light Beams - 0 views

www.physorg.com/news166779852.html

PHY

shared by Joris _ on 15 Jul 09 - Cached
  • it’s possible that a physical object (e.g. a quantum field) in one location could emerge at another location in the same quantum state
  • pacome delva on 16 Jul 09
     
    have to be carefull this article is really badly written. Teleportation is not some matter that disapear from somewhere to reappear somewhere else... Usually we talk about entangled particles (by essence quantum theory is non-local), and teleportation means that if you force (with a measurement) one particle to take a particular quantum state then the other one will have the same quantum state. There it seems that the same could be done with a quantum field, which is the second quantization of the quantum theory: the state of a quantum field can contain a mixture of n-particles states (meaning that the number of particles is not defined, only the mean value). If you measure the number of particle then you force the quantum field to "choose" a particular quantum state (which can be the vacuum). Teleportation means that you will have exactly the same measure on another quantum field, which is somehow intricated to your first one.
ESA ACT

Light and Matter: educational materials for physics and astronomy - 0 views

www.lightandmatter.com

phy book online

shared by ESA ACT on 24 Apr 09 - Cached
  • ESA ACT on 24 Apr 09
     
    online books on physics
jcunha

A practical polariton laser - Nature Photonics - 2 views

www.dropbox.com/...ctical%20polariton%20laser.pdf

PHY photonics light-matter coupling polariton

shared by jcunha on 03 Nov 14 - No Cached
  • jcunha on 03 Nov 14
     
    One overview about a recent publication (10/06/2014 http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.236802) showing room temperature operation of a new type of laser 'discovered' in 2013, the polariton laser. This new type of laser shows extremely low threshold current density - 2 orders of magnitude below Vertical Cavity Surface Emitting Lasers (VCSEL) - and it is believed to become one important component of nanophotonic integrated components.
1 - 16 of 16
Showing 20▼ items per page