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| bio | website | jfitzsimons.org |
|---|---|---|
| location | Singapore, Singapore | |
| age | 31 | |
| visits | member for | 2 years, 6 months |
| seen | May 18 at 22:33 | |
| stats | profile views | 454 |
I have just moved to the Center for Quantum Technologies in Singapore, after spending the last 3 years as a Merton College JRF in Theoretical Physics and a Senior Research Fellow in Oxford University Department of Materials. My research focuses largely on theoretical aspects of quantum information processing. In particular I am interested in spin networks, measurement based computation, cryptography and computational complexity.
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Dec 2 |
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Examples of number theory showing up in physics @Artem: It's true that you can arrive at above result via finite fields, but the structure of the partial results is governed by number theoretic properties. I don't really see the way of arriving at a given result as particularly fundamental, as there are often multiple paths to the result. |
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Dec 2 |
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What videos should everyone watch? You may want to expand the question with a bit more explanation as in the cstheory question. I've marked this CW. |
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Dec 1 |
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Examples of number theory showing up in physics This seems more like engineering a physical system to embody certain number theoretic properties, rather than them occurring unexpectedly. |
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Dec 1 |
asked | Examples of number theory showing up in physics |
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Dec 1 |
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What papers should everyone read? @TsuyoshiIto: I must admit I didn't check the claim that it was 4 pages. |
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Nov 28 |
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Quantum causal structure @lurscher: Good catch. I'm not really sure where things stand then. I've updated my answer to include the reference in your comment. |
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Nov 27 |
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Causality and operationalism: from sets and functions to monads "Of course, states don't exist, only processes do." - That's one hell of a statement. Perhaps we would be better sticking to physics than philosophy. |
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Nov 26 |
answered | Quantum causal structure |
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Nov 25 |
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Quantum causal structure @Peter: Sorry Peter, I was referring to the original question, not your comment. I don't dispute that the quantum gravity case is open, but we know so little about that area that it is hardly surprising that it is open. I know some of the results the question refers to, but can't make much sense of what the poster has in mind. I'll cast a virtual vote to close, but since my vote is binding, I won't actually close the question yet. I'd like to give the OP time to actually explain what they mean. If nothing happens in a few days, I'll kill the question. |
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Nov 25 |
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Quantum causal structure I don't understand what you mean by quantum causal structure. Quantum mechanics is non-signalling so causal structure is the same as in the classical case. |
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Nov 25 |
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Hilbert-Schmidt basis for many qubits - reference +1 from me. I use it a lot too, but couldn't think of anything interesting to say! |
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Nov 24 |
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What papers should everyone read? Four pages is hardly unusual in physics. |
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Nov 21 |
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CHSH violation and entanglement of quantum states @PiotrMigdal: Perhaps you should post that as an answer. |
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Nov 16 |
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Accurate quantum state estimation via “Keeping the experimentalist honest” @ChrisFerrie: Sorry, I meant if the measurements can depend on $\sigma$ not $\rho$. I've edited my above comments to reflect this. |
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Nov 15 |
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Accurate quantum state estimation via “Keeping the experimentalist honest” And hence you need only measure in the $X$ basis, even though this does not have sufficiently many linearly independent outcomes to uniquely identify an arbitrary density matrix. |
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Nov 15 |
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Accurate quantum state estimation via “Keeping the experimentalist honest” This argument is for the case where the set of measurements is fixed and independent of $\sigma$. If the scheme need only work for certain classes of $\sigma$ then this imposes correlations between entries in the density matrix which reduces the number of linearly independent measurement operators required to uniquely identify it. An example of this is where $\sigma = |+\rangle\langle +|$, where purity implies that the state has expectation value 0 for $Z$ and $Y$ measurements, and if $\mbox{Tr}(\rho X) = \mbox{Tr}(\sigma X)$ then $\mbox{Tr}(\rho Y) = \mbox{Tr}(\sigma Y)$, etc. |
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Nov 15 |
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Accurate quantum state estimation via “Keeping the experimentalist honest” Also, if you take any complete or over-complete basis for tomography you can make the measurements and make them arbitrarily weak, you still satisfy the criterion (though Alice's expected loss tends towards zero as the measurement tends towards the identity). |
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Nov 15 |
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Accurate quantum state estimation via “Keeping the experimentalist honest” @ChrisFerrie: No, that is not the same as the sufficient condition I gave since I only required linear independence and not orthogonality and only for a sufficiently large subset of $\{E_i\}$, so it includes a bunch of weak measurements. However that was only an example. The necessary and sufficient condition is that all expectation values are the same. This includes a huge range of measurements, such as measuring a randomly chosen Pauli operator, which yields only a single bit of information. |
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Nov 14 |
answered | Accurate quantum state estimation via “Keeping the experimentalist honest” |
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Nov 12 |
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Length of publication cycle for peer-reviewed journals that's the time I meant. It really depends on the referees you get. |
