This series covers all areas of research at Perimeter Institute, as well as those outside of PI's scope.
In the last few years there has been a burst of
progress in the field of massive gravity. The construction of consistent
theories in which the graviton has a small mass has in turn led to the
development a new family of compelling, consistent low-energy modifications of
General Relativity. These theories improve our understanding of the
interplay between gravity and particle physics and provide new approaches to
solving the cosmological constant problem. In this talk I will review
While the luminosity and mass distributions of quasars
has evolved dramatically with cosmic time, the physical properties of quasars
of a given luminosity are remarkably independent of redshift. I will describe recent results on the spectra
of luminous quasars, the dark matter halos in which they sit, and the
intergalactic medium of their host galaxies, that are essentially
indistinguishable from moderate redshifts to z>6.
Advanced LIGO (aLIGO) and Advanced Virgo (AdV) are kilometer-scale
gravitational wave (GW) detectors that are expected to yield the first
direct observations of gravitational waves. I will describe the
currently projected schedule, sensitivity, and sky
localization accuracy for the GW detector network in the next decade.
I
will discuss some basic notions in the theory of phonology (sound systems
in language). The sounds of a language are generally assumed to be
composed of smaller constituents, called features. The features that
make up a sound cannot be directly obtained from its pronunciation, but
rather must be inferred from the system of contrasts that are at play
in a particular language. How to determine which features are contrastive
presents a logical and empirical puzzle that may be interesting
I give an account of the Machian approach to dynamics,
from Mach's critique of Newton to the work of Barbour, Bertotti, York and
O'Murchadha, which culminated in the theory of Shape Dynamics, a new and
original way of thinking about General Relativity. I conclude commenting on the
present research lines in Shape Dynamics, and the opportunity it offers to
solve the problem of time in quantum gravity.
Support
for this colloquium is provided by The Templeton Frontiers Program.
Gravity
in string theory is a generalized version of Einstein's theory with some
universal features that call for a reformulation
The Rosenbluth Method is a classical kinetic growth Monte
Carlo algorithm for growing a self-avoiding walk by appending steps to its
endpoint.
This algorithm
A revolution is underway in the construction of ‘artificial atoms’ out
of superconducting electrical circuits.
These macroscopic ‘atoms’ have quantized energy levels and can emit and
absorb quanta of light (in this case microwave photons), just like ordinary
atoms. Unlike ‘real’ atoms, the
properties of these artificial atoms can be engineered to suit various
particular applications, and they can be connected together by wires to form
quantum ‘computer chips.’ This so-called
The solutions to
the cosmological constant problems may involve modifying the very long-range
dynamics of gravity by adding new degrees of freedom. As an example of a conservative and minimal
such modification, we consider the possibility that the graviton has a very
small mass. Massive gravity has received
renewed interest due to recent advances which have resolved its traditional
problems. This kind of modification has
some peculiar and unexpected features, and it points us towards a universe
which looks quite unfamiliar.