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Fermilab | Chad Orzel | Sean Carroll | David Tong | Perimeter Institute

Fermilab – Don Lincoln

Fermilab’s YouTube channel has many online videos on topics in physics.

Here’s one on Quantum Field Theory with some interesting animation.

Published on Jan 14, 2016 – The subatomic world has long been known to be truly mind-bending, with particles that are waves and vice versa.  Cats are alive and dead and everything is governed by probability. While this remains true, science has progressed since the invention of quantum mechanics and scientists currently use an extended form of quantum mechanics called quantum field theory or QFT.  QFT teaches us that all particles are waves that interact with one another.  If you thought the quantum world was weird before, modern ideas can give you a headache. In this video, Fermilab’s Dr. Don Lincoln tells us all about it.

In modern physics theory, one can picture all subatomic particles as beginning with a field. Then the particles we see are just localized vibrations in the field. So, according to quantum field theory, the right way to think of the subatomic world is that everywhere- and I mean everywhere- there are a myriad of fields. Up quark fields, down quark fields, electron fields, etc. And the particles are just localized vibrations of the fields that are moving around.

So those are the essential features of quantum field theory. Theoretical physics simply imagines that ordinary space is full of fields for all known subatomic particles and that localized vibrations can be found everywhere. These fields can interact with one another, like two adjacent tuning forks. These interactions explain how particles are created and destroyed – basically the energy of some vibrations move from one field and set up vibrations in another kind of field.

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In QFT, the energy of the electron field sets up a localized vibration of a photon field which then moves away
Fermilab’s “Higgs Boson 2016” video reflects on the 2012 discovery.

Published on Nov 16, 2016 – The Higgs boson burst into the public arena on July 4, 2012, when scientists working at the CERN laboratory announced the particle’s discovery. However the initial discovery was a bit tentative, with the need to verify that the discovered particle was, indeed, the Higgs boson. In this video, Fermilab’s Dr. Don Lincoln looks at the data from the perspective of 2016 and shows that more recent analyses further supports the idea that the Higgs boson is what was discovered.

You often hear people say that Higgs bosons interact more with heavy particles and that’s true. But there is a better way to say that. The correct way to say it is that particles that interact more with the Higgs field and boson get more mass. This is very subtle point, so I’ll say it again. It’s not that heavy particles interact more with the Higgs field. It’s that particles that interact more with the Higgs field become heavy. It’s the interaction with the field that comes first and the mass is the consequence. So how can we test this? Given this connection between the mass of particles and the degree to which the Higgs field interacts with them, we can predict into which particles the Higgs boson prefers to decay and which it doesn’t.

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Particle masses in GeV

Chad Orzel

Exotic Physics of an Ordinary Morning | Chad Orzel | TEDxAlbany” (~17′ Published on Dec 21, 2015): Starting with a toaster oven, Chad Orzel discusses everyday experiences related to topics in quantum physics.

Schrödinger’s cat: A thought experiment in quantum mechanics – Chad Orzel

Published on Oct 14, 2014 — Austrian physicist Erwin Schrödinger, one of the founders of quantum mechanics, posed this famous question: If you put a cat in a sealed box with a device that has a 50% chance of killing the cat in the next hour, what will be the state of the cat when that time is up? Chad Orzel investigates this thought experiment.

Lesson by Chad Orzel, animation by Agota Vegso.

What is the Heisenberg Uncertainty Principle? – Chad Orzel

Published on Sep 16, 2014 — The Heisenberg Uncertainty Principle states that you can never simultaneously know the exact position and the exact speed of an object. Why not? Because everything in the universe behaves like both a particle and a wave at the same time. Chad Orzel navigates this complex concept of quantum physics.

Lesson by Chad Orzel, animation by Henrik Malmgren.

 

Sean Carroll

Cosmology and the arrow of time: Sean Carroll at TEDxCaltech” (~16′ Uploaded on Feb 25, 2011)

Keeping the Universe very, very smooth at early times is not easy. It’s a delicate arrangement. It’s a clue that the early Universe is not chosen randomly, there was something that made it that way, and we would like to know what. So part of our understanding of this was given to us by Ludwig Boltzmann, an Austrian physicist in the 19th century, and Boltzmann’s contribution was that he helped us understand entropy.

David Tong

Quantum Fields: The Real Building Blocks of the Universe
The Royal Institution – Published on Feb 15, 2017

According to our best theories of physics, the fundamental building blocks of matter are not particles, but continuous fluid-like substances known as ‘quantum fields’. David Tong explains what we know about these fields, and how they fit into our understanding of the Universe. Tong is a professor of theoretical physics at Cambridge University, specialising in quantum field theory.

Here’s the Q&A after the above lecture by David Tong.

What came first, quantum fields or the big bang? How can equation that we don’t fully understand be written at all? David Tong answers questions from the audience following his talk.

Q: … would you accept that despite the fact you’ve described that everything’s built up of fields and just interactions, ultimately there is there must always be some granularity and so the Greeks were essentially right?

A: No. [Laughter] Just no. There is a question … the question is at a fundamental level is nature discrete or continuous.

I see no evidence whatsoever for discreteness, or all the discreteness that we see in the world is something which emerges from an underlying continuum; so, that’s certainly a correct statement about the laws of physics as we currently understand it.

Now it may be that you go to a deeper level the discreteness takes over again. I don’t think so. Yeah you know … I wrote an article in Scientific American actually that elaborates on this in some detail. No, the quanta are emergent. So, for example, if you look at you know the Schrodinger equation is the equation of quantum mechanics and it’s what spits out the quanta of quantum mechanics — the fact that energy levels come in in discrete bits. There’s nothing discrete about the Schrodinger equation. The Schrodinger equation is something to do with a smooth field like like wave function. The discreteness is something which emerges when you solve the Schrodinger equation, so it’s not built into the heart of nature.

 

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Standard Model
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Taken at face value this equation makes no sense whatsoever; so what we are doing here is trying to sum over all possible fields … if you get rid of gravity we then understand this equation — it’s just we can’t solve it.

Perimeter Institute

1. Nobel laureate Art McDonald Public Lecture:
A Deeper Understanding of the Universe from 2 km Underground
Perimeter Institute for Theoretical Physics

Published on Apr 14, 2016
Dr. Art McDonald explains how researchers created an ultra-clean lab two kilometres underground in an active nickel mine to study fundamental physics, astrophysics, and cosmology, during his Perimeter Institute Public Lecture on April 13, 2016.

McDonald shared the 2015 Nobel prize in physics “for the discovery of neutrino oscillations, which shows that neutrinos have mass.” He presents an overview of his personal journey studying the “ghost particle” and establishig the underground research facility for that purpose.

2. Neil Turok Public Lecture:
The Astonishing Simplicity of Everything
Perimeter Institute for Theoretical Physics

Published on Oct 8, 2015
On Oct. 7, 2015, Perimeter Institute Director Neil Turok opened the 2015/16 season of the PI Public Lecture Series with a talk about the remarkably simplicity that underlies nature. Turok discussed how this simplicity at the largest and tiniest scales of the universe is pointing toward new avenues of physics research and could lead to revolutionary advances in technology.

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After discussing the history of mathematics for some key numbers (e, i, h) Perimeter Institute Director Neil Turok highlights those numbers in the equation for all known physics.