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bio website jessriedel.com
location Yorktown Heights, NY
age 28
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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.


Aug
9
comment Can “vacuum be brought” from outer space?
Thanks. This is the recent (2009) microsatellite stuff I alluded to. But note that this doesn't include reentry. I've never seen a good write up about the minimal vehicle size for reentry. Would love to know what's been done.
Aug
9
comment Can “vacuum be brought” from outer space?
Jim, it would be great if you could link us to a description of a similar mission (take a few kg to LEO and then bring it back to Earth) that cost less than $1 million.
Aug
9
comment Can “vacuum be brought” from outer space?
It's \$10k/kg, but that doesn't mean you can put 10 kg in orbit for $100k. There are fixed costs, and rockets have certain minimum sizes (generally with payloads that are many thousands of kilos). Such low costs may be possible with recent attempts with shared launches for microsatellites, but remember that you need a re-entry vehicle. I don't know if there are any that are so light.
Aug
9
comment Can “vacuum be brought” from outer space?
Many of the answers so far are getting hung up about the cost. learner didn't ask what the cost is, and there are plenty of interesting things to be learned by considering this as pure thought experiment.
Aug
9
answered Can “vacuum be brought” from outer space?
Jul
25
revised an example of a quantum system for which wigner function transitions to negative values
added 330 characters in body
Jul
25
awarded  Revival
Jul
25
comment an example of a quantum system for which wigner function transitions to negative values
You're off by a 45 degree rotation in your definition of the Wigner function. The usual notation is that $\rho(x_1,x_2) = \langle x_1 | \rho | x_2 \rangle$. In this case, the Wigner function is the result of Fourier transforming $\rho(x+\Delta x/2,x-\Delta x/2)$ with respect to the variable $\Delta x$, not $\rho(x_1,x_2)$ with respect to $x_2$.
Jul
25
answered an example of a quantum system for which wigner function transitions to negative values
Jul
25
comment Wigner characteristic function
I gave an intuitive discussion of the Wigner quasiprobability distribution on my blog: blog.jessriedel.com/2014/04/01/…
Jul
25
answered Wigner characteristic function
Jul
25
comment Wigner characteristic function
You've written down the Wigner function (sometimes called the Wigner quasiprobability distribution), not the Wigner characteristic function. They are symplectic Fourier transforms of each other. See Wikipedia.
Jul
2
awarded  Curious
Jul
1
comment One question about renormalization
I suggest coming up with a more informative title. This will increase interest in this question.
Jun
25
comment Problem in Grandfather paradox
I don't think your distinction between dynamical and information paradoxes is a good one. Much better is to think of the well-posedness of dynamical systems: given equations of motion, the solution ought to exist and be unique. The grandfather paradox is just a colorful illustration of the failure of existence, and the unexplained book is just an illustration of the failure of uniqueness. (I believe the subjective value of the proof is a red herring.)
Jun
16
revised Is there a formalism for talking about diagonality/commutativity of operators with respect to an overcomplete basis?
Added references
Jun
13
comment Is there a formalism for talking about diagonality/commutativity of operators with respect to an overcomplete basis?
If anyone knows if these ideas can be generalized to other types of overcomplete bases besides the coherent states, I would be very interested to learn about it.
Jun
13
answered Is there a formalism for talking about diagonality/commutativity of operators with respect to an overcomplete basis?
Jun
12
revised What are the requirements on conditional unitaries for overcomplete bases?
added 1106 characters in body
Jun
11
comment Nonequilibrium thermodynamics in a Boltzmann picture
Boltzmann's equation is phenomenological and isn't derived from first principles. In fact, the inadequacy of this approach was what motivated me to ask the above question in the first place. (At the time I was reading back through Ch 14 of Kittel and Kroemer, and all the other stat mech books I could find, e.g. Landau, had the same argument.)