Decoherence Definition and 179 Threads

I am currently trying to resolve a question in my head that I am sure is covered in basic quantum mechanics but have been unable to find a clear definitive answer. Hope the forum can provide insight or direct me to a reference that would help? Recently mechanical vibration of entangled atomic...

Hello I am reading this book: "[URL and the appearance of a classical word&f=false"]decoherence[/URL] I hope someone could help me. Please go to Appendix A1 Joos introduces the notation f(q,q'). What is the dimension of f from his notation? Next page he writes that \int f^2 d\Omega...

Here are the Pirsa video talks by Robin Blume-Kohout: http://pirsa.org/index.php?p=speaker&name=Robin_Blume-Kohout I've just seen one talk, that he gave October 1, just a couple of weeks back. The topic is Quantum Knowledge. http://pirsa.org/09100089/ What is it. What is quantum data...

So if you remember, Loschmidt's paradox is about "Loschmidt's paradox, also known as the reversibility paradox, is the objection that it should not be possible to deduce an irreversible process from time-symmetric dynamics" ( http://en.wikipedia.org/wiki/Loschmidt's_paradox ) My question is...

Decoherence may involve the minimization or constancy of states. (Physics of the Impossible, by Michio Kaku, page 248.) Entropy involves the maximization of states. (Any statistical mechanics textbook.) 1. Does one eventually overcome the other as time approaches infinity? 2. Could there be...

I have no technical knowledge of this area, but I would like to know in what ways studying the decoherence process with Bose-Einstein condensates might tell us how this process works. Can BECs allow us to see the process in "slow motion" so to speak? EDIT: I guess I should first ask if...

I have read any number of books regarding the various interpretations of QM. Personally I find certain of the interpretations (i.e many worlds, consciousness causing the collapse of the wave function, etc.) somewhat of a stretch. It would now seem that the theory of decoherence has elegantly...

I'm hoping that someone has the patience to help a poor ignorant layman understand... and be warned that I am mathematically impotent. My struggle is in wrapping my mind around the concept of decoherence driven quantum collapse. As I understand it, the interaction between particles causes a...

I've been thinking about the many-worlds interpretation and how one might test it experimentally. I'm wondering if it might be possible to observe interference between macroscopic systems in different "worlds". We start with an isolated quantum system in superposition, and we let it interact...

In the double slit experiment, and observer such as a photon can hit an electron and thereby interact with. ie, a photon either hits an electron, or it doesn't. In this case, the photon hitting an electron induces decoherence. If we make a similar analogy with water, ie. a water molecule...

Here, in Saint Petersburg, Russia I open a box with a Schroedinger cat I get immediately decoherenced so I see only one cat - dead or alive How soon that decoherence 'hits' you in the US? Photons can not travel directly to another part of the globe, they get absorbed/reemitted, losing the...

Hi, All As I know quantum reality (bird’s view) is transformed into the world we observe (frog’s view) via the process called quantum decoherence. Based on wiki, http://en.wikipedia.org/wiki/Decoherence (as I understand it) this is just mathematical result of mapping a quantum reality into a...

Back in August I asked a question on this forum about Zurek's paper "Decoherence and the Transition from Quantum to Classical—Revisited" and got no response. I am sure many of the folks on this list have read this paper in which Zurek states that entropy increases upon decoherence (that's how...

"decoherence" - the myth It's interesting when one hears supposedly fact-based scientists claim that decoherence has resolved the "measurement problem". Having been brought up on a staple of QM texts I was flabbergasted when i heard these kind of statements claiming decoherence was the...

I was reading about quantum computing and I came across this: http://en.wikipedia.org/wiki/Quantum_computing#Quantum_decoherence It seems to suggest that fast logic gates don't decoher qubits while slow ones due. If this is true, it would seem like the term "measurement" in QM is a function...

I'm trying to make sense of various explanations of why decoherence causes interference to disappear, but I'm afraid I don't quite grok it. There's a bit of explanation in this thread. And some more on wikipedia. The first link starts with |\psi{\rangle} = |a{\rangle} + |b{\rangle} and...

Hello, I have two questions I wish to ask concerning Decoherence and entanglement: 1. I am certainly no expert on quantum mechanics, and while I was reading I stumbled upon the concept of decoherence. I understand the idea, but I have a few questions concerning it: 1. theoretically, if the...

ok I just read something that doesn't make much sense to me. It said that quantum computers can only use reversible logic gates because irreversible gates generate heat/lost information. It makes sense to me that everything in physics is reversible and that NAND gates produce heat because...

When reading in the web about decoherence especially in popular articles I find very often explanations that point out the fact that the environment has a large number of degrees of freedom. It is unclear to me in which extent and in which aspects this is relevant for decoherence. My...

Assume one photon of a momentum entangled pair of photons is absorbed by an isolated atom. Is there now an entanglement between the other photon and this atom? If so, in what way is the atom entangled with the photon? If the atom after a while emits a photon, under what conditions would the...

Recent double-slit experiments with massive molecules, such as fluoro-fullerene consisting of 108 atoms and atomic mass 1632, http://physicsweb.org/articles/world/18/3/5/1", show that the interference fringe will disappear if the FF molecule emits a thermal photon, or collides with a gas...

Hi all, 1)What are the principal results of the decoherence in QM? 2) Is there a general theorem we can use to determinate the states of macroscopic bodies (huge number of particles)? 3) if yes, what are the known limitations? Terra Incognita

This thread is based on some reading I've done on decoherence (a lot of it by Zurek) and recent experiments involving decoherence and complementarity. One interesting item is the recent experiment by Anton Zeilinger and team involving C60 molecules interacting to produce and interference pattern...

This is a link that shows a visual depiction of decoherence: http://www.geocities.com/scjphysicist/decoh.html and this is a link with the technical details of decoherence: http://www.ece.rochester.edu/~habif/Web/Research/decoherence.htm Is the second link saying that measuring one...

http://www.quantum.univie.ac.at/res...matterwave/c60/ This weblink is about C60 buckyballs passing through a diffraction grating and showing wave-like behaviour.Since the buckyballs are moving quite slowly - about 210 m/s would it be possible to fire a neutron beam through the buckyballs...

Hi, I am reading Brian Greene's new book "The Fabric of the Cosmos". In the book, Brian Greene talks about the Quantum Measurement Problem, different interpretations of QM, decoherence, etc... Rather than attributing the collapse of the probability wave to things like conscious or human...

i know very little quantum mechanics and would appreciate as qualitative a reply as anyone can muster... what is the physical mechanism for decoherence? decoherence sounds like a solution to quantum 'weirdness' if i understand it correctly...you have to take into account a myriad quantum...

From what I have gathered, whether or not decoherence has solved the measurement problem is still a matter of debate. But to those who say that it does, my question is: how does it solve it? Does it actually cause the collapse of the wavefunction? These questions are actually pieces of a...

Does observation decohere the object, or also interfere with the observer, to manifest macroscopic reality? A classical measurement might result either from equilibrium of object phase itself or of phase difference relative to the observer. How, then, do these large-scale effects of object...