6,380 reputation
2044
bio website jfitzsimons.org
location Singapore, Singapore
age 33
visits member for 4 years, 10 months
seen Jun 12 at 16:59

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.


Jan
17
comment How can one build a multi-scale physics model of fluid flow phenomena?
This is not my area at all, so this might be a particularly ignorant comment, but can you not simply simulate a small section at the microscopic level for a range of different conditions for the boundaries, and then piece together these into a solution for a larger volume, repeating several times if necessary? The basic idea being that there are many areas for which exactly the same calculation is necessary, and probably relatively few distinct such calculations, so better to build a lookup table than to calculate anew each time.
Jan
13
comment Readable books on advanced topics
Ah, I've just looked at a few reviews, and this probably fits my query better than I first thought. Sorry.
Jan
13
comment Readable books on advanced topics
As I commented on ver's post, I am not looking for popularizations, but rather advanced texts that manage to be readable at the same time.
Jan
13
comment Readable books on advanced topics
Perhaps I should have made it clearer, but I am not looking for popularizations.
Jan
11
comment Readable books on advanced topics
Ah yes. Actually, I already have that one!
Jan
11
asked Readable books on advanced topics
Jan
6
comment Information geometry of 1D Ising model in complex magnetic field regime
@WNY: I meant that if you plug such a Hamiltonian into the time dependent Schroedinger equation you get completely unphysical results. I understand from the above comments that you are simply using complex analysis on the conventional Hamiltonian, so I think my confusion has been cleared up. Sorry.
Jan
6
comment Information geometry of 1D Ising model in complex magnetic field regime
While I have a reasonable amount of experience with the Ising model, I'm not quite clear how exactly it makes sense to make $h$ complex. The dynamics of the system would then not only not be unitary, but would not even conserve total probability. Could you clarify?
Dec
29
comment Applications of Geometric Topology to Theoretical Physics
@AndrásBátkai: I'm not sure I agree that this should be CW. Let's wait to see if any one has a strong opinion either way.
Dec
29
comment Applications of Geometric Topology to Theoretical Physics
Have you heard about topological quantum computing? It is very closely linked to braid theory, which has given rise to a quantum algorithm for approximating the Jones polynomial.
Dec
20
comment Depolarizing threshold for CSS codes
@AshleyStephens: Great edit! Perhaps it should have been an answer it it's own right.
Dec
17
answered Depolarizing threshold for CSS codes
Dec
12
comment Higgs Field - Is its discovery truly “around the corner”?
@LarianLeQuella: I think perhaps you will not get answers before tomorrow. I imagine those in the know are embargoed from talking about it until tomorrow.
Dec
11
comment Spekkens Toy Model, Internal Comonoids
Welcome to the site, Ross!
Dec
9
comment Uniqueness of eigenvector representation in a complete set of compatible observables
That is incorrect. The Hamiltonian itself is an observable. Further, if you assign an arbitrary set of unique eigenvalues to the same eigenvectors (picking a basis for each degenerate subspace), thus lifting the degeneracy, this produces an observable which is simultaneously diagonalizable with the Hamiltonian, and hence commutes with it, but which has no degenerate eigenspaces.
Dec
7
comment Uniqueness of eigenvector representation in a complete set of compatible observables
@Moshe: I didn't bother looking at the Physics.SE link before answering, but now you've pointed it out I agree that genetth's answer was perfect.
Dec
6
comment Uniqueness of eigenvector representation in a complete set of compatible observables
Secondly, in quantum mechanics observable and Hermitian operator are synonymous. You can construct a physical measurement (in principle at least) for any Hermitian operator, and any physical observable is Hermitian.
Dec
6
comment Uniqueness of eigenvector representation in a complete set of compatible observables
$\psi_i$ above are a basis for the Hilbert space in which all measurements are diagonal. If the set of measurements is maximal then it necessarily contains $D$ for some specific choice of basis. Since you specify the set of observables by their eigenvectors, you can explicitly construct $D$.
Dec
6
answered Uniqueness of eigenvector representation in a complete set of compatible observables
Dec
2
comment Examples of number theory showing up in physics
That's weird, and certainly interesting. I'll give the paper a look.