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location Cambridge, United Kingdom
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visits member for 3 years, 1 month
seen Jul 21 at 22:42

Researcher in quantum information --- involving algebras over finite dimensional Hilbert spaces, graphs and combinatorics, and vector spaces over ℤ/pℤ.

I habitually edit and re-edit anything I write, as long as I have the time, interest, and ability. I should probably apologize for this tendency, but you will probably have to be satisfied with being warned about it instead.


Aug
20
awarded  Yearling
Jul
2
awarded  Curious
Jun
18
comment Subgroups of the Clifford Group
You ask what "progress" there has been made in (etc.), which implies that you are asking about what developments there has been from some starting point. What is it that you already know? Are you just asking whether there exists some characterization? Do you mind if there isn't a characterization, but a description of some subgroups of the Clifford group which are isomorphic to the Pauli group? Do you care if you get an answer which restricts to inner automorphisms of $\mathrm{GL}(2^n)$ or do you want a more complete theory? What base knowledge are you assuming when you say "progress"?
Jun
18
comment Subgroups of the Clifford Group
Progress, from which starting point?
Jun
8
comment Why do they call it quantum teleportation?
Apart from that, your understanding is essentially correct: there can be no distinction in the measurement statistics of B, without information from A and C. The joint system ABC has correlations which can only be witnessed using communication.
Jun
8
comment Why do they call it quantum teleportation?
"...at which time B will immediately exhibit different behavior upon measurement": I would suggest that this way of thinking is misleading. How is B "behaving" before or after measurement? There can be no noticeable change, because any process which would cause the "before" and "after" states to appear different, would be acting as a measurement on B before the joint measurement on A+C, disentangling B from A.
Mar
5
answered Can Information Travel Faster Than The Speed Of Light?
Feb
27
awarded  Notable Question
Jan
18
awarded  Nice Answer
Jan
8
comment How can the reduction postulate be removed with the other postulates of QM still leading to correct predictions?
If you do not track the state of the aparatus, you cannot track the state of the record of the apparatus, which is to say the measurement outcome; and therefore you cannot track whether or not the outcomes of multiple measurements are consistent.
Jan
7
comment How can the reduction postulate be removed with the other postulates of QM still leading to correct predictions?
If you consider measurement as an interaction between the apparatus and the system, repeated measurement (with fresh subsystems for the different measurement records) will give rise to strongly correlated measurement outcomes, due to the entanglement between the measurement outcomes and the post-measurement state.
Dec
5
comment In QM, do we deal with basis or orthonormal sets?
What is your question?
Dec
5
revised In QM, do we deal with basis or orthonormal sets?
fixed math typesetting and edited typos
Dec
5
comment A (mundane) CS analogy for quantum teleportation
In short: "Isn't it likely the state is described by some property of the qubit that we have no way of measuring?" No --- and that is precisely what is meant by saying that it cannot be described by local hidden variables.
Dec
5
comment A (mundane) CS analogy for quantum teleportation
No: I mean that there is no way to model the entangled state as involving any randomly generated bits (using 'genuine' randomness or otherwise) for which the measurement outcome is a function of those random bits. Not only does entanglement produce 'genuine' randomness, it produces randomness by a means which does not have any analogue in classical random variables, and the reason for this is ultimately because it would also produce a uniformly random outcome for any choice of measurement.
Dec
4
answered A (mundane) CS analogy for quantum teleportation
Nov
27
comment Explanation for the power of quantum computers
The fractional bit interpretation doesn't come from quantum information. In fact, such a model of a spin as consisting of several sub-bits in this manner cannot possibly work, as it represents a local hidden variable model.
Nov
5
revised Do systems with level crossings have unstable eigenbases?
added 780 characters in body
Nov
5
revised Do systems with level crossings have unstable eigenbases?
corrected foolish error re: eigenvectors of \Delta
Nov
5
revised Do systems with level crossings have unstable eigenbases?
added 432 characters in body