# Video Library

Since 2002 Perimeter Institute has been recording seminars, conference talks, and public outreach events using video cameras installed in our lecture theatres.  Perimeter now has 7 formal presentation spaces for its many scientific conferences, seminars, workshops and educational outreach activities, all with advanced audio-visual technical capabilities.  Recordings of events in these areas are all available On-Demand from this Video Library and on Perimeter Institute Recorded Seminar Archive (PIRSA)PIRSA is a permanent, free, searchable, and citable archive of recorded seminars from relevant bodies in physics. This resource has been partially modelled after Cornell University's arXiv.org.

## Making sense of non-Hermitian Hamiltonians

Wednesday Nov 24, 2010
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The average quantum physicist on the street believes that a quantum-mechanical Hamiltonian must be Dirac Hermitian (invariant under combined matrix transposition and complex conjugation) in order to guarantee that the energy eigenvalues are real and that time evolution is unitary. However, the Hamiltonian $H=p^2+ix^3$, which is obviously not Dirac Hermitian, has a real positive discrete spectrum and generates unitary time evolution, and thus it defines a fully consistent and physical quantum theory.

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## Conformal Field Theory (PHYS 609) - Lecture 3

Wednesday Nov 24, 2010
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## Mathematical Physics (PHYS 624) - Lecture 3

Wednesday Nov 24, 2010
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## Small thermal machines

Tuesday Nov 23, 2010
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The second law of thermodynamics tells that physics imposes a fundamental constraint on the efficiency of all thermal machines.
Here I will address the question of whether size imposes further constraints upon thermal machines, namely whether there is a minimum size below which no machine can run, and whether when they are small if they can still be efficient? I will present a simple model which shows that there is no size limitation and no limit on the efficiency of thermal machine and that this leads to a unified view of small refrigerators, pumps and engines.

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## Fermions, holography, and consistent truncations

Tuesday Nov 23, 2010
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We discuss the coupling of fermions to holographic superconductors in 3+1 and 4+1 (bulk) dimensions. We do so from a top-down perspective, by considering the reduction of the fermionic sector in recently found consistent truncations of type IIB and D=11 supergravity on squashed Sasaki-Einstein manifolds, which notably retain a finite number of charged (massive) modes. The truncations in question also include the string/M-theory embeddings of various models which have been proposed to describe systems with non-relativistic scale invariance via holography.

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## Conformal Field Theory (PHYS 609) - Lecture 2

Tuesday Nov 23, 2010
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## Mathematical Physics (PHYS 624) - Lecture 2

Tuesday Nov 23, 2010
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## Mathematical Physics (PHYS 624) - Lecture 1

Monday Nov 22, 2010
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## Conformal Field Theory (PHYS 609) - Lecture 1

Monday Nov 22, 2010
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## Effective Conformal Theory and the Flat-space Limit of AdS

Friday Nov 19, 2010
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The idea of an effective conformal theory describing the low-lying spectrum of the dilatation operator in a CFT is developed. Such an effective theory is useful when the spectrum contains a hierarchy in the dimension of operators, and a small parameter whose role is similar to that of 1/N in a large N gauge theory. These criteria insure that there is a regime where the dilatation operator is modified perturbatively.

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## Next Public Lecture

### EMILY LEVESQUE: THE WEIRDEST STARS IN THE UNIVERSE

Wednesday Mar 07, 2018

## RECENT PUBLIC LECTURE

### Robert Spekkens: The riddle of the quantum sphinx: quantum states and category mistakes

Speaker: Robert Spekkens