Recent content by beautiful1

pawelsobko, I do not know if there is a definite answer, as the solution may depend on whether you think of the wavefunction as a statistical tool or a 'real' thing. Either way, I have read a report about how Gisin's group tried to measure the 'speed' of quantum teleportation, with the...

Bump I started this thread over a year ago, and today I wanted to see if anyone had any new information regarding openly reported, experimentally measured teleportation fidelities.

Just to add my two cents to this point..it is more about how many gate operations can be performed before the systems irrevocably decoheres. The distinction being that (relatively) long decoherence times do not help if it also takes a (relatively) long time to perform an operation.

As I understand your question, you are asking what would happen if the measurement device did not record what result was measured. If it is possible, even if only in principle, for an observer to infer which path the particle passes through, then the interference effects vanish. In your...

The Fourier representation is a representation of the function in the sinusoidal basis. The quantity \tilde{A}(\mathbf{p},n) is the (Fourier) amplitude at coordinate (p, n). Because the vector potential A is real, the Fourier amplitudes satisfy certain symmetry conditions. BTW, I think you...

You may also find this critique of the above paper interesting as well http://arxiv.org/abs/quant-ph/9803030

Well said.

Boschi et al., Phys. Rev. Lett. v80, p1120 (1998) 0.853±0.012 (polarization-encoded, k-vector entangled two photon system) Fursawa et al., Science, v 282, p 706 (1998) 0.58±0.02 (two-mode-squeezed quadrature states) Kim et al., Phys. Rev. Lett., v86, p1370 (2001) ~0.83±...

As I understand this, the "tags", or distinguishing information, you describe are themselves observables, which means that they can be measured. And, in fact, if you make a "tag" measurement, you expect the result to identify the path with which that outcome corresponded (assuming of course that...

I've not read the book, or the passage, you discuss, but I noticed in your desciption that you emphasized "OUR KNOWLEDGE of the which-path information". In general, explicit knowledge of the which-path information is not necessary for an interference effect to be compromised. The key...

Hello all, I am looking for references to experimentally measured quantum teleporation fidelities. In particular, I am trying to find what is the best fidelity to date. So far I have: Bouwmeester et al., Nature v390, p575 (1997), 0.70±0.3 (with polarization-encoded qubits, before subtracting...

Though its not the case you mentioned, it is also possible that electronic angular momentum may yield a \Delta J = 0 selection rule. This may occur when a rotational transition accompanies an electronic transition between, say, a \Sigma singlet state to a\Pi singlet state. In this case, the...

Can we think about a probability distribution? In that case, it seems that an isoenergy contour would trace the boundary to whatever level of accuracy you wanted. And if you have the Hamiltonian you could just set H to this constant to put a constraint on p and q. But if they are really...

touqra, great follow up question. like ZapperZ said, it is information about the photon that is transferred but not the photon itself. Photons have two orthogonal (perpendicular) polarizations, called H and V for horizontal and vertical. Quantum mechanics allows for superpositions of these...

alfredblase: yeah what physics monkey said...not instantaneous, not even faster than light, instead requiring one classical and one quantum communication channel. p.s. I know some groups (Gisin, Geneva) have tried to measure a "speed" for information transfer via a quantum channel, i.e...