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location Cambridge, United Kingdom
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visits member for 2 years, 8 months
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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.


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
Nov
5
answered Do systems with level crossings have unstable eigenbases?
Nov
5
revised Do systems with level crossings have unstable eigenbases?
specifically asked for a counterexample
Nov
4
revised Do systems with level crossings have unstable eigenbases?
minor elaboration
Nov
4
revised Do systems with level crossings have unstable eigenbases?
minor elaboration
Nov
4
asked Do systems with level crossings have unstable eigenbases?
Nov
4
comment Adiabatic evolution for initial Hamiltonian on Hadamard basis and problem Hamiltonian as diagonal
Statements aren't NP-hard. Problems (a family of related yes-or-no questions) can be, however. If you only mean to ask whether or not your statement is true, you should remove the reference to NP-hardness.