913 reputation
317
bio website jessriedel.com
location Yorktown Heights, NY
age 28
visits member for 2 years, 1 month
seen 11 hours ago

Physics post-doc at IBM Watson research center in Yorktown Heights, NY. Interested in quantum information, foundations, and decoherence. And maybe dark matter.

Ph.D. UCSB Physics 2012 (advisor: Wojciech Zurek). B.A. Princeton Physics 2007. TJHSST 2003.


1d
revised Off-diagonal terms of the Husimi $Q$ function?
added 17 characters in body; added 27 characters in body
1d
asked Off-diagonal terms of the Husimi $Q$ function?
Apr
4
revised Nonequilibrium thermodynamics in a Boltzmann picture
added 873 characters in body
Apr
2
comment Is contextuality required in quantum mechanics?
Peter, I think Spekkens mentions this worry in the conclusions, although he leaves it for future work: "The question of whether an experimental test of contextuality is even possible has been the subject of some controversy, due to the finite precision of real experimental procedures. The problem...is that finite precision might imply that in practice no two experimental procedures are found to be operationally equivalent.... A possible resolution of this finite precision loophole is to further generalize the definition..."
Mar
31
revised What happens to gravity after matter-antimatter annihilation?
spelling
Mar
28
asked Nonequilibrium thermodynamics in a Boltzmann picture
Mar
28
answered What happens to gravity after matter-antimatter annihilation?
Mar
4
comment Entangled or unentangled?
To expand on twistor59's comment: In this case, an important restriction is that the fermions are indistinguishable. In a traditional Bell state we can make any measurement on either system individually. But in a 1st quantized picture of 2 fermions occupying 2 modes, there's no way to make a measurement on just 1 of the fermions. It is a virtue of the 2nd quantized picture that this apparent restriction is shown be a confusion: you can't distinguish between the two fermions because they aren't two different objects. They just count the excitation of the more fundamental objects, the modes.
Feb
28
awarded  Yearling
Jan
30
comment Noether's current expression in Peskin and Schroeder
This is the best derivation of Nother's theorem for physicists I've seen on the web. Most are hopelessly vague about what's being held constant, what a deformation is, and the difference between the quantities called $J^\mu$ and $K^\mu$ here. The others overwhelm physicists with needless technical complications, and lack generality. Well done.
Jan
30
comment Derivation of Noether's theorem - A problem with physical significance
Noether's theorem shows that there is a conserved quantity for every physical symmetry. The action being invariant under a transformation is the definition of a symmetry transformation. You could just as easily state the theorem as "for every transformation preserving the action, there is a conserved quantity". Is that useful?
Jan
30
comment Can Noether's theorem be understood intuitively?
The image can be found here. It was discussed in this later Physics.SE question.
Jan
21
answered Online QFT video lectures
Nov
14
comment Is the universe fundamentally deterministic?
Other good references for understanding what decoherence can and cannot say about the measurement problem: Schlosshauer, Zurek. (That second one was my advisor.)
Nov
14
comment What are the fastest electron orbitals
My guess is that the OP could use a little more explanation. Why would the 1-s orbital of ununoctium be faster than 2-p of oxegen? Why magnetars?
Nov
9
asked Is there a formalism for talking about diagonality/commutativity of operators with respect to an overcomplete basis?
Oct
27
asked Can I usefully interpret a non-unital completely positive (CP) map as a cooling process?
Oct
21
revised Reconstruction of “wavefunction” phases from $|\psi(x)|$ and $|\tilde \psi(p)|$
grammar/spelling
Oct
21
comment Reconstruction of “wavefunction” phases from $|\psi(x)|$ and $|\tilde \psi(p)|$
Yes, your counter-example is a discrete version of mine. (I'm happy to combine our answers, although I don't know how that's done.) A natural follow-up question is whether the pair (|f(x)|^2, |f(p)|^2) is sufficient to uniquely determine a state up to time-reversal. Based on your dimensional argument, I suspect it is (perhaps with additional discrete symmetries undetermined).
Oct
21
comment Reconstruction of “wavefunction” phases from $|\psi(x)|$ and $|\tilde \psi(p)|$
@Trimok, is this sufficient to answer your question, or are you looking for something more?