6,232 reputation
1943
bio website jfitzsimons.org
location Singapore, Singapore
age 32
visits member for 4 years, 1 month
seen Nov 17 at 5:14

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.


Nov
9
comment What Shannon channel capacity bound is associated to two coupled spins?
@AramHarrow: To explain what I mean: Imagine you have two spin-1/2 systems. Then your coupling induces at most 4 distinct eigenspaces which pick up relative phase, independent of the number of ancillae, or how they are prepared prior to coupling. Given that the information transfer in periods of free evolution is determined entirely by the relative phases between these 4 spaces, this is identical to what can be achieved with two spins. The only subtlety then comes from how you can combine multiple uses of such a channel.
Nov
9
comment What Shannon channel capacity bound is associated to two coupled spins?
@AramHarrow: Good point. However, it seems like you can bound the effective dimensionality via the number of splittings in the eigenvalues of local Hamiltonians.
Nov
8
comment Explicit construction for unitary extensions of CPTP maps?
@Marcin: I deleted it because there was an error in the proof.
Nov
7
answered What Shannon channel capacity bound is associated to two coupled spins?
Nov
5
awarded  Yearling
Nov
3
comment Decoherence and measurement in NMR
@JohnSidles: Standard quantum limit often refers to separable states only, whereas the Heisenberg limit is in metrology the Heisenberg limit is the "performance that can't be bettered supposing that standard QM is true".
Nov
2
comment Decoherence and measurement in NMR
@JohnSidles: As it happens I have a paper with some others on exactly the question of the extraction of information from a spectrometer beyond the standard quantum limit (arXiv:1007.2491).
Nov
2
comment A resource theory of quantum discord?
+1 from me. Welcome to the site Animesh.
Nov
2
comment Decoherence and measurement in NMR
@Kaveh_kh: Yes I know, but I think this is a much stronger effect than the weak measurements actually being made on the system, and I suspect is actually coherent, which would affect the time dynamics (which are important since the spectrometer is essentially measuring change with respect to time).
Nov
2
comment Decoherence and measurement in NMR
I took his concern to be about the current creating a field which effects the spectrum, rather than about the fact that you are making weak measurements.
Nov
1
comment Decoherence and measurement in NMR
I don't quite follow. How would a low quality coil prevent back action?
Oct
24
comment Linearizing Quantum Operators
@Qmechanic: Argh! I wish people wouldn't do that. It makes it impossible to keep track of whether it has been answered or not.
Oct
24
comment How to write a paper in physics
You also want to give your readers a hint, since if it is an important result you get a wider range of readers, and many may not necessarily be familiar with all of the tools you use.
Oct
24
comment Linearizing Quantum Operators
Could you link to the paper?
Oct
23
comment Paper listing known Seiberg-dual pairs of N=1 gauge theories
Maybe, but it really seems to require a huge time investment by anyone giving such an answer. Perhaps a better approach would be via community wiki, where people simply edit the top answer to add in any they are aware of that are not already listed.
Oct
23
comment Paper listing known Seiberg-dual pairs of N=1 gauge theories
@Yuji: It is unfortunate that you haven't gotten a definitive answer, but if it doesn't already exist in the literature, it seems unlikely that you will find anyone here with the requisite background knowledge prepared to spend the time it takes to go through 1000 papers to generate the list.
Oct
23
answered How to write a paper in physics
Oct
22
comment Negative probabilities in quantum physics
What on earth are you talking about?
Oct
18
comment What methods are there to deal with quantum spatiotemporal chaos?
I'm not quite sure what you mean by "the qualitative distribution" of a one dimensional cellular automata. Could you clarify this? Two alternating species are sufficient for Turing completeness, given an appropriate update rule.
Oct
18
answered Graduate School for Theoretical Physics