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location Cambridge, United Kingdom
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visits member for 3 years, 9 months
seen May 16 at 5:33

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.


Apr
30
awarded  Taxonomist
Feb
12
comment Is it possible to transfer classical bits of information faster than light speed?
@ErikAronesty: But probabilities are not signals. An event at A does not reveal anything about a joint event on (A,B), except of course for the part which has to do with what happened at A. As for the deduction: that is happening entirely within your head based on what you have observed from light-like signals --- your deduction does not go forth and impose structure upon the world: you are merely swept into a contingency (corresponding to a "possible world"), the partial knowledge of which spreads outward at light speed from those sources which have been swept into the same contingencies.
Jan
5
awarded  Popular Question
Jan
4
comment Schrodinger's dead cat when the evidence is destroyed
@Zarko: indeed, sequential Stern-Gerlach strikes at the heart of what I find mysterious about QM, and to me points out the problems with Bayesian and related interpretations (not that MWI actually clarifies anything here).
Dec
5
awarded  Popular Question
Sep
30
awarded  Explainer
Sep
24
awarded  Autobiographer
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