Theoretical Physics - From Outer Space to Plasma-logo

Theoretical Physics - From Outer Space to Plasma

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Members of the Rudolf Peierls Centre for Theoretical Physics host a morning of Theoretical Physics roughly three times a year on a Saturday morning. The mornings consist of three talks pitched to explain an area of our research to an audience familiar with physics at about the second-year undergraduate level and are open to all Oxford Alumni. Topics include Quantum Mechanics, Black Holes, Dark Matter, Plasma, Particle Accelerators and The Large Hadron Collider.

Members of the Rudolf Peierls Centre for Theoretical Physics host a morning of Theoretical Physics roughly three times a year on a Saturday morning. The mornings consist of three talks pitched to explain an area of our research to an audience familiar with physics at about the second-year undergraduate level and are open to all Oxford Alumni. Topics include Quantum Mechanics, Black Holes, Dark Matter, Plasma, Particle Accelerators and The Large Hadron Collider.
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Location:

United States

Description:

Members of the Rudolf Peierls Centre for Theoretical Physics host a morning of Theoretical Physics roughly three times a year on a Saturday morning. The mornings consist of three talks pitched to explain an area of our research to an audience familiar with physics at about the second-year undergraduate level and are open to all Oxford Alumni. Topics include Quantum Mechanics, Black Holes, Dark Matter, Plasma, Particle Accelerators and The Large Hadron Collider.

Language:

English


Episodes

Cosmic acceleration revealed by Type la supernovae?

11/1/2019
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In this talk Subir Sarkar will explain how deflagration supernovae have been used to infer that the Hubble expansion rate is accelerating, and critically assess whether the acceleration is real and due to `dark energy’.

Duration:00:40:58

Supernova Explosions and their Role in the Universe

11/1/2019
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In this talk, Philipp Podsiadlowski will explain how this energy (sometimes) creates a visible fireball, before going on to explain the role of supernovae in the production of the heaviest elements in the periodic table.

Duration:00:48:49

What makes stars go bang?

11/1/2019
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In this talk, James Binney will outline the physics that leads to prodigeous release of energy in core-collapse and deflagration supernovae.

Duration:00:46:51

... from collisions to the Higgs boson

5/16/2019
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To study the Higgs boson at the LHC we also need to understand how highly energetic quarks and gluons interact, among themselves and with the Higgs. These interactions are described by quantum field theory, a beautiful mathematical framework that combines quantum mechanics with Einstein’s theory of special relativity. In recent years, our understanding of quantum field theory has progressed significantly, allowing us to develop a new generation of accurate theoretical predictions for key LHC...

Duration:00:35:01

From protons to collisions…

5/16/2019
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We learn about the Higgs Boson and its interactions at the LHC by examining the debris produced by colliding protons head-on at unprecedented high energies. However, we know from our theory of strong interactions - quantum chromodynamics (QCD) - that protons themselves are highly complex bound states of more fundamental 'quarks', held together by the force carriers of QCD, the 'gluons'. The question is then: how do we go from the collision of these complicated protons to a theoretical...

Duration:00:36:13

What the Large Hadron Collider is telling us about the Higgs sector and its new interactions

5/16/2019
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Over the past two years, CERN’s Large Hadron Collider (LHC) has started to directly probe a qualitatively new class of interactions, associated with the Higgs boson. These interactions, called Yukawa interactions, are unlike any other interaction that we have probed at the quantum level before. In particular, unlike the electromagnetic, weak and strong forces, they have an interaction strength that does not come in multiples of some underlying unit charge. Yukawa interactions are believed to...

Duration:00:44:51

Why the world is simple - Prof Ard Louis

2/15/2019
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The coding theorem from algorithmic information theory (AIT) - which should be much more widely taught in Physics! - suggests that many processes in nature may be highly biased towards simple outputs. Here simple means highly compressible, or more formally, outputs with relatively lower Kolmogorov complexity. I will explore applications to biological evolution, where the coding theorem implies an exponential bias towards outcomes with higher symmetry, and to deep learning neural networks,...

Duration:00:38:47

Topology in Biology - Prof Julia Yeomans FRS

2/15/2019
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Active systems, from cells and bacteria to flocks of birds, harvest chemical energy which they use to move and to control the complex processes needed for life. A goal of biophysicists is to construct new physical theories to understand these living systems, which operate far from equilibrium. Topological defects are key to the behaviour of certain dense active systems and, surprisingly, there is increasing evidence that they may play a role in the biological functioning of bacterial and...

Duration:00:38:38

Welcome from the Head of the Physics Department

2/15/2019
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Ian Shipsey delivers the welcome speech for the Saturday Mornings of Theoretical Physics.

Duration:00:13:41

Entropy from Entanglement

12/3/2018
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Siddharth Parameswaran, Associate Professor, Physics Department. The usual picture of entropy in statistical mechanics is that it quantifies our degree of ignorance about a system. Recent advances in cooling and trapping atoms allow the preparation of quantum systems with many interacting particles isolated from any external environment. Textbook discussions of entropy — that invoke the presence of a “large” environment that brings the system to thermal equilibrium at a fixed temperature ---...

Duration:00:42:12

Entropy: two short stories

12/3/2018
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John Chalker, Head of Theoretical Physics, gives a talk on entropy. Thermodynamics and statistical mechanics give us two alternative ways of thinking about entropy: in terms of heat flow, or in terms of the number of micro-states available to a system. John Chalker will describe a physical setting to illustrate each of these. By applying thermodynamics in a realm far beyond its origins, we can use the notion of an ideal heat engine to find the temperature of a black hole. And by applying...

Duration:00:39:53

Entropy: Gaining Knowledge by Admitting Ignorance

12/3/2018
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Alexander Schekochihin, Professor of Theoretical Physics, gives a talk on entropy. When dealing with physical systems that contain many degrees of freedom, a researcher's most consequential realisation is of the enormous amount of detailed information about them that she does not have, and has no hope of obtaining. It turns out that this vast ignorance is not a curse but a blessing: by admitting ignorance and constructing a systematic way of making fair predictions about the system that...

Duration:00:52:31

Networked Quantum Information Technologies

7/6/2018
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This talk reviews the developments in quantum information processing.

Duration:00:21:09

Quantum logic with trapped-ion qubits

7/6/2018
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This talk reviews testing and developing ideas in quantum computing using laser-manipulated trapped ions.

Duration:00:25:16

The ultimate limits of privacy and randomness...for the paranoid ones

7/6/2018
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This talk explains how qubits are used to represent numbers in a way that permits 'quantum-mechanical parallel' computing. We show how this can used to achieve fast factorisation of large numbers, and hence the breaking of current codes. We end by explaining how entangled pairs of particles can be used to provide an alternative and entirely secure cryptographic system.

Duration:00:54:51

“Open” Quantum Systems

7/6/2018
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This talk reviews how to deal with quantum systems that are coupled to the outside world, as in reality all systems are. We first introduce density operators and explain how quantum states give rise to them. We then turn to measures of entanglement that can be computed from a density operator, and show that entanglement grows with time. Finally, we show how the interaction with the environment gives rise to the phenomenon of decoherence.

Duration:00:47:29

Quantum Systems from Group up

7/6/2018
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This talk reviews the modern formulation of the basic ideas of quantum mechanics. We start by explaining what quantum amplitudes are, how they lead to the idea of a quantum state and how these states evolve in time. We then discuss what happens when a measurement is made before describing correlated ('entangled') systems. Applying these ideas to two-state systems ('qubits') we point out that the complexity of computing the evolution of an N qubit system grows like exp(N)

Duration:00:40:13

Galaxy Dynamics: The chemical evolution side

1/25/2018
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Dr Ralph Schoenrich will talk about the chemical evolution side Spiral density waves patterns re-distribute stars throughout the entire system, making it impossible to know a star's origin from just its kinematics. However, stars are more than just points in phase space: every star is labelled with the elemental abundances of the gas cloud from which it was formed. Over the last few years a number of observational campaigns have started to measure these labels for millions of stars in our...

Duration:00:39:04

Galaxy Dynamics: The dynamics of galaxy discs

1/25/2018
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Dr John Magorrian will talk about the dynamics of galaxy discs In galaxy discs it is energetically favourable for angular momentum to move outwards and mass to move inwards. This transportation is effected by spiral arms, but what causes them? Simple linear response calculations demonstrate that even the smallest perturbation is amplified manyfold, while the differential rotation of the disc means that the response is stretched out into a spiral-like pattern. John Magorrian will introduce...

Duration:00:44:24

Galaxy Dynamics: Stellar systems: a new state of matter

1/25/2018
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Prof James Binney FRS will talk about stellar systems: a new state of matter The long range of gravity means that many concepts from undergraduate statistical mechanics do not apply: energy is not extensive; there is no microcanonical or canonical ensemble. Stars and dark matter particles have long mean free paths, which means that to a very good approximation their motion is determined by the mean-field gravitational potential. James Binney will identify a hierarchy of timescales,...

Duration:00:51:19