Posts tagged as:

physics

QED meets General Relativity

November 8, 2010

“Quantum gravitational contributions to quantum electrodynamics” (D. Toms, Nature, 4 Nov.) is the most exciting paper I’ve seen on quantum field theory and gravitation in a long time. It offers no speculations about strings, extra dimensions, new symmetries, or the like, and no loop quantum gravity or causal dynamical triangulations, just a carefully cross-checked mathematical [...]

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The 2010 Nobel Prize
for Graphene Nanotechnology

October 5, 2010

Andre Geim and Konstantin Novoselov have just won the 2010 Nobel Prize in Physics “for groundbreaking experiments regarding the two-dimensional material graphene”, and their work has opened a broad frontier in nanotechnology.
Graphene is best known for its remarkable electronic properties, which make it both a wonderland for physicists and a contender for future transistors with [...]

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Causal sets as discrete models of spacetime

May 19, 2010

I finally understand how a discrete model of spacetime can be Lorentz invariant.
To see the problem, note that a spacetime divided into little Planck-length parts would look different in a boosted reference frame — the lengths would differ. (A proposed workaround, “doubly-special relativity,” has been severely challenged at a very basic level.)
A recent review gives [...]

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Chemists deserve more credit:
Atoms, Einstein, and the Matthew Effect

February 17, 2010

Chemists understood the atomic structure of molecules in the 1800s, yet it is often said that Einstein established the existence of atoms in a paper on Brownian motion, “Die von der Molekularkinetischen Theorie der Wärme Gefordete Bewegung von in ruhenden Flüssigkeiten Suspendierten Teilchen”, published in 1905.
This is perverse, and has seemed strange to me [...]

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Condensed-Matter Physics Condensed

December 7, 2008

In reading up on metal oxides, spin systems, and computation, I found a wonderful 19-page “Perspective of Frontiers in Modern Condensed Matter Physics” [pdf], published in the AAPPS Bulletin last April by Caltech physicist Nai-Chang Yeh. Its scope ranges from symmetry, Landau, and intellectual history, to topological orders and spin liquids, even touching on solid-phase [...]

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