April 25: Matthew Schwartz (Harvard)

Time: 2pm
Place: 2N36
 
Title: Tunneling in Quantum Field Theory and the Fate of the Universe
 
Abstract:
One of the most concrete implications of the discovery of the Higgs
boson is that, in the absence of physics beyond the standard model, the
long term fate of our universe can now be established through precision
calculations. Are we in a metastable minimum of the Higgs potential or
the true minimum? If we are in a metastable vacuum, what is its
lifetime? To answer these questions, we need to understand tunneling in
quantum field theory. As we delve into how tunneling works, we find many
unusual elements: complex quantities which should be real,
gauge-dependent quantities which should be physical, an hbar expansion
which differs from the ordinary loop expansion, and ultraviolet degrees
of freedom that don't decouple. This talk will discuss some of these
elements and present some new perspectives on quantum tunneling.