.

Origins of Slowly Fading Super-Luminous Supernovae

November 12, 2013

Super-luminous supernovae that radiate more than 1044 ergs per second at their peak luminosity have recently been discovered in faint galaxies at redshifts of 0.1–4. Some evolve slowly, resembling models of 'pair-instability' supernovae. Such models involve stars with original masses 140–260 times that of the Sun that now have carbon–oxygen cores of 65–130 solar masses. In these stars, the photons that prevent gravitational collapse are converted to electron–positron pairs, causing rapid contraction and thermonuclear explosions. Many solar masses of 56Ni are synthesized; this isotope decays to 56Fe via 56Co, powering bright light curves.

.

Unconventional Sequence of Fractional Quantum Hall States in Suspended Graphene

October 19, 2013

Graphene provides a rich platform to study many-body effects, owing to its massless chiral charge carriers and the fourfold degeneracy arising from their spin and valley degrees of freedom. Graduate student Ben Feldman, Prof. Amir Yacoby, and colleagues from Max-Planck-Institut in Stuttgart used a scanning single-electron transistor to measure the local electronic compressibility of suspended graphene, and observed an unusual pattern of incompressible fractional quantum Hall states that follows the standard composite fermion sequence between filling factors ν = 0 and 1 but involves only even-numerator fractions between ν = 1 and 2.

.

Cambridge-Connecticut AMO Open House

October 10, 2013

Cambridge-Connecticut AMO Open House

Department of Physics, 17 Oxford Street, Jefferson 250

“bottom-up”  (Vladan Vuletic)
“top-down” (Martin Zwierlein)
“molecules” (Kang-Kuen Ni)
“hybrid systems and applications” (Misha Lukin)
9:00–11:00 AM — Lectures

Department of Physics, Library Jefferson 450

11:30–2:30 PM — Poster Session/Boxed Lunches

Symposium Celebrating Daniel Kleppner’s 80th Birthday

Sanders Theatre, 45 Quincy Street, Cambridge

.

Attractive Photons in a Quantum Nonlinear Medium

October 1, 2013

Figure reprinted by permission from Macmillan Publishers Ltd: Nature ©2013

The fundamental properties of light derive from its constituent particles - massless quanta (photons) that do not interact with one another. However, it has long been known that the realization of coherent interactions between individual photons, akin to those associated with conventional massive particles, could enable a wide variety of novel scientific and engineering applications.

Pages