Christoph

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	2,073 reputation	bio	website		visits	member for	1 year, 5 months
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Sep 2	revised	Official definition of astronomical units edited body
Sep 2	revised	Official definition of astronomical units added 50 characters in body
Sep 2	answered	Official definition of astronomical units
Aug 22	comment	Is it possible to transfer classical bits of information faster than light speed? transfer of information faster than light == causal relationship across space-like separation; the whole point of inflation is that it can explain the uniformity of the CMB without violating Einstein causality
Aug 22	comment	Is it possible to transfer classical bits of information faster than light speed? @Chris: THEN inflation sets in - the signal has already been transmitted at that point
Aug 22	comment	Is it possible to transfer classical bits of information faster than light speed? inflation doesn't help with getting a signal from A to B - in fact, it's harmful because of increase in distance and cosmological redshift
Aug 21	answered	Is it possible to transfer classical bits of information faster than light speed?
Aug 20	revised	Why do people categorically dismiss some simple quantum models? added 7 characters in body
Aug 20	answered	Why do people categorically dismiss some simple quantum models?
Aug 17	revised	How does non-hermitian quantum mechanics (PT-symmetric QM) fit in physics? added 790 characters in body
Aug 16	answered	How does non-hermitian quantum mechanics (PT-symmetric QM) fit in physics?
Aug 15	revised	QM without complex numbers added 988 characters in body
Aug 15	comment	In 't Hooft beable models, do measurements keep states classical? @annav: my argument is valid for ordinary QM - no idea if there's a better one for t'Hooft's model...
Aug 15	comment	In 't Hooft beable models, do measurements keep states classical? @annav: the complex structure is related to the 2-out-of-3 property; the real and imaginary parts of the hermitian product are symmetric and anti-symmetric forms which induce a metric and symplectic structure on the projective Hilbert space; the metric structure provides the probabilities and the symplectic one the dynamics via Hamilton's equations; if we require metric and symplectic structure to be compatible, we get an almost-complex structure for free even if we consider the projective space as a real manifold
Aug 14	answered	Is it possible to build an instrument which can travel faster than light?
Aug 13	comment	number of microstates associated with two-level quantum systems @diffeomorphism: the qubit state space $P_1\mathbb C$ is diffeomorphic to $S^2$ via Hopf fibration, see Bloch sphere
Aug 13	comment	number of microstates associated with two-level quantum systems @diffeomorphism: each pure quantum state corresponds to a single microstate, ie entropy doesn't apply (or would be zero); entropy comes in once you add classical probabilities on top of the quantum ones via the density matrix formalism
Aug 13	comment	Negative Mass and gravitation Coulomb's law of electrostatics and Newton's law of gravity might look pretty similar, but the Maxwell equations and Lorentz' force don't look much like Einstein's field equation and the geodesic equation
Aug 11	revised	Is temperature an extensive property, like density? added 2 characters in body
Aug 11	comment	Is temperature an extensive property, like density? @Arnold: I added two paragraphs to my answer - feel free to complain if you there's something wrong with what I wrote...