6,360 reputation
2044
bio website jfitzsimons.org
location Singapore, Singapore
age 33
visits member for 4 years, 7 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.


Aug
27
comment Reversing gravitational decoherence
@RonMaimon, I mean that gravity couples the system to its environment, and so you get a change in the environment over time depending on the state of the system, and hence the reduced density matrix becomes mixed. As regards unitaries, I was refering to the general case. Even if you think about a static EM field, this induces a unitary transformation on the system (no decoherence, but it is altered) and to recover the initial state you need to apply another unitary. In the general case, states can become delocalised, mixing the reduced density matrix, even if the global state remains pure.
Aug
27
answered Reversing gravitational decoherence
May
4
awarded  Talkative
May
4
awarded  Mortarboard
May
4
awarded  Enlightened
May
4
awarded  Enlightened
May
4
awarded  Enlightened
May
4
awarded  Nice Question
May
4
awarded  Nice Answer
May
4
awarded  Nice Answer
May
4
awarded  Student
May
4
awarded  Scholar
May
4
awarded  Good Question
May
4
awarded  Good Question
May
4
awarded  Nice Question
May
4
awarded  Nice Question
May
4
awarded  Nice Answer
May
4
awarded  Nice Answer
May
1
comment What can the D-Wave quantum computer do?
@episanty: That is true of every problem in PSPACE. It might be that P=PSPACE, but we're pretty sure it's not true. But again, the only real evidence is that we can't prove equality.
Apr
18
comment Higgs mass and the hierarchy problem
I fixed your latex. You can include it yourself by enclosing it in dollar signs (like an inline equation in latex).