6,004 reputation
1641
bio website jfitzsimons.org
location Singapore, Singapore
age 32
visits member for 3 years, 5 months
seen Dec 6 '13 at 16:11

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.


Oct
16
comment Connections of iterative solvers for large systems of equation in Physics?
What type of equations?
Oct
16
comment direct sum of anyons?
+1: A far clearer answer than mine.
Oct
16
comment direct sum of anyons?
@André: Check out Chapter 2 of the first link. They are specifically using qubits encoded in $\mathbb{I} + \mathbb{I}$. Specifically these correspond to the two different ways to fuse four anyons to obtain the vacuum. There are several ways this can be achieved. (see for example quant-ph/0703143 where anyons are encoded as topological defects in a lattice of qubits)
Oct
16
comment Does the complex 3-sphere have a complex structure modulus?
Can you point us towards the section in the paper where that claim is made (it's a long paper)?
Oct
16
comment direct sum of anyons?
@Heidar: Sorry, hadn't seen your answer when I posted this. I guess we were writing them at the same time.
Oct
16
answered direct sum of anyons?
Oct
13
awarded  Nice Answer
Oct
13
comment Models of higher Chern-Simons type
It is certainly fine to answer your own question if you later find the answer. It's certainly preferable to having unanswered questions.
Oct
12
comment Random Walk Randomly Reflected
@RonMaimon: I have an answer for the asymmetric case too (somewhat different to yours), but it might make more sense to wait for the other question, since it is a completely different argument.
Oct
12
comment Random Walk Randomly Reflected
@Leandro: No problem. As far as I can see this question actually amounts to a random walk on a weighted graph with a certain structure. The most obvious generalization would be a walk on a weighted directed graph, which would give you the direction dependent reflectors.
Oct
11
comment Random Walk Randomly Reflected
@Leandro: No problem.
Oct
11
answered Random Walk Randomly Reflected
Oct
10
answered experimental bounds on spacetime torsion
Oct
10
answered Principle behind fidelity balance in quantum cloning
Oct
10
comment What do theoretical physicists need from computer scientists?
Prakash is something of a special case, as he has a significant background in physics.
Oct
6
comment What is the use of a Universal-NOT gate?
I think universal decoupling pulses may be possible, but we know for a fact that the universal-NOT isn't.
Oct
6
comment Random Walk Randomly Reflected
How are you measuring distance from the oracle? Is it the Euclidean norm?
Oct
6
comment Does entropy measure extractable work?
Actually I guess the issue is clouded by the existence of alternative non-equivalent definitions of entropy.
Oct
6
comment What is the use of a Universal-NOT gate?
Yes, dynamical decoupling is one reason you may want a universal-NOT. However, given that these don't exist, you are likely far better with WaHuHa pulses and refinements there of, than using approximate universal-NOTs. After all, you only need the effective change to add up to zero, and having more than two types of evolution involved doesn't change that end result (see my comment on Marco's answer above). +1 anyway though, as it is indeed a reason for wanting a universal-NOT.
Oct
6
comment Does entropy measure extractable work?
@Matt: Good answer, and you get +1 from me, but I do not understand the claim that thermodynamic entropy is not well defined for non-equilibrium systems. It's given by $-k_B \sum_i p_i\log p_i$ where $p_i$ is the probability of the $i^{th}$ microstate. This is obviously defined for non-equilibrium systems and equilibrium systems alike.