This series covers all areas of research at Perimeter Institute, as well as those outside of PI's scope.
Currently, no general theory exists that explains what life is. While many definitions for life do exist, these are primarily descriptive, not predictive, and they have so far proved insufficient to explain the origins of life, or to provide rigorous constraints on what properties we might expect all examples of life to share (e.g., in our search for life in alien environments).
In an ordinary quantum field theory, the "split property" implies that the state of the system can be specified independently on a bounded subregion of a Cauchy slice and its complement. This property does not hold for theories of gravity, where observables near the boundary of the Cauchy slice uniquely fix the state on the entire slice. The original formulation of the information paradox explicitly assumed the split property and we follow this assumption to isolate the precise error in Hawking's argument. A similar assumption also underpins the monogamy paradox of Mathur and AMPS.
When a generic isolated quantum many-body system is driven out of equilibrium, its local properties are eventually described by the thermal ensemble. This picture can be intuitively explained by saying that, in the thermodynamic limit, the system acts as a bath for its own local subsystems. Despite the undeniable success of this paradigm, for interacting systems most of the evidence in support of it comes from numerical computations in relatively small systems, and there are very few exact results.
Fast radio bursts (FRB's) are a recently discovered, poorly understood class of transient event, and understanding their origin has become a central problem in astrophysics. I will present FRB science results from CHIME, a new interferometric telescope at radio frequencies 400-800 MHz.
We will discuss quantum singular value transformation (QSVT), a simple unifying framework for quantum linear algebra algorithms developed by Gilyén, Low, Su, and Wiebe. QSVT is often applied to try to achieve quantum speedups for machine learning problems. We will see the typical structure of such an application, the barriers to achieving super-polynomial quantum speedup, and the state of the literature that's attempting to bypass these barriers.
We will begin by explaining the black hole information paradox, starting from first principles. We will then explain how computations in string theory yield a resolution of this paradox. When we make a bound state of strings and branes, then this bound state is found to swell up into a horizon sized `fuzzball'; this fuzzball radiates like a normal body without any information loss.
The double copy relates scattering amplitudes in gauge theory and gravity. But interaction potentials (and spacetime metrics) can be extracted from amplitudes, and so the double copy leads to a relationship between classical solutions of gauge theory and gravity. In this talk I will describe this relationship, provide a perspective on the Schwarzschild metric as a “square” of the Coulomb charge, and take a look at the “square root” of the Kerr metric.
In the last few years there have been demonstrations of quantum advantage using noisy quantum circuits that are believed to go beyond the limits of the classical computers that exist today. In this talk I will give an overview of a different type of quantum advantage that can be attained by shallow (short-depth) quantum circuits. I will discuss recent results which establish unconditionally that constant-depth quantum circuits can solve certain linear algebra problems faster than their classical counterparts.
In 1930, the famous statistician and geneticist Ronald Fisher claimed to have proved a "fundamental theorem of natural selection". He compared this result to the second law of thermodynamics, and described it as holding "the supreme position among the biological sciences". But others found it obscure, and in its most obvious interpretation it is simply false. Luckily there is a true result closely resembling Fisher's claim: a general theorem connecting dynamical systems and information theory. I'll explain this, give the very simple proof, and draw a few conclusions.
Information theory is an invaluable tool for studying questions around the foundations of physics. In thermodynamics, for example, it provides the key to resolving apparent contradictions, such as the famous Maxwell's demon paradox. Conversely, information theory lends itself to the conception of novel paradoxes, such as the black hole information paradox, which helps us sharpening our physical intuition. One may therefore ask whether an information-theoretic perspective can also yield insights on the nature of time.