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From Materials to Cosmology: Studying the early universe under the microscope

Series
Oxford Physics Public Lectures
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Physics Colloquium 27 January 2017 delivered by Professor Nicola Spaldin, ETH Zurich

The behaviour of the early universe just after the Big Bang is one of the most intriguing basic questions in all of science, and is extraordinarily difficult to answer because of insurmountable issues associated with replaying the Big Bang in the laboratory. One route towards the answer -- which lies at the intersection between cosmology and materials physics -- is to use laboratory materials to test the so-called "Kibble-Zurek" scaling laws proposed for the formation of defects such as cosmic strings in the early universe. Here Professor Spaldin will show that a popular multiferroic material -- with its coexisting magnetic, ferroelectric and structural phase transitions -- generates the crystallographic equivalent of cosmic strings. Professor Spaldin will describe how straightforward solution of the Schroedinger equation for the material allows the important features of its behaviour to be identified and quantified, and present experimental results of what seem to be the first unambiguous demonstration of Kibble-Zurek scaling in real materials. Professor Spaldin will end with some very recent data showing that things might be less unambiguous than they seem.
 

Episode Information

Series
Oxford Physics Public Lectures
People
Nicola Spaldin
Keywords
Physics
universe
big bang
Kibble-Zurek
cosmic strings
cosmology
Department: Department of Physics
Date Added: 05/04/2017
Duration:

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The Ontology of Autonomy for Autonomous Weapons Systems

Series
Changing Character of War
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Dr Heather Roff discusses the role of autonomous weapons systems within the international community. She provides a theoretical framework for defining and classifying these systems, examining the diplomatic and moral concerns that they pose.

For the past three years the international community convened a series of informal meetings of experts under the auspices of the United Nation’s Convention on Certain Conventional Weapons (CCW) to consider whether or not to preemptively ban lethal autonomous weapons systems under an additional protocol to the Convention. The debate has circled the same set of concerns: what exactly lethal autonomous weapon systems (AWS) are and whether it is incumbent upon states to ban them before they are developed. Without a definition states argue they cannot know what exactly it is they are supposed to ban. Yet after three years of expert testimony, there is no agreement on any meaningful definition. Diplomatic considerations are pressing, but Dr Heather Roff believes that the source of this confusion is due to an antecedent and more profound concern, one that is inherently tied to the question of defining what constitutes an AWS. In plain terms, it is a concern with the authorization to make war and the subsequent delegation of this authority. Until now, humans have been the sole agents authorized to make and to wage war, and questions of authorization and war have never been technologically dependent. Rather, they have been moral considerations and not empirical ones. She attempts to provide a theoretical framework for defining and classifying autonomous weapons systems. By so doing, she argues the moral quandary over autonomous weapons has its roots in concerns over the delegation of a (moral) faculty: the authority to wage war.

Episode Information

Series
Changing Character of War
People
Heather Roff
Keywords
weapons
war
politics
Department: Pembroke College
Date Added: 05/04/2017
Duration:

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Technology and the Rise of Boundless Warfare

Series
Changing Character of War
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Professor David Galbreath gives a talk for the Changing Character of War seminar series.

Episode Information

Series
Changing Character of War
People
David Galbreath
Keywords
conflict
technology. warfare
war
Department: Pembroke College
Date Added: 05/04/2017
Duration:

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Social Pluralism Religious Cleansing and Hybrid Warfare in Syria

Series
Changing Character of War
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Since the ‘Arab Spring’ uprising of 2011, the United States and a network of European and regional Sunni allies have applied instruments of coercion against Syria that collectively take on the character of ‘hybrid warfare’.

In this conflict, Washington and its alliance partners have undertaken a wide range of lethal and non-lethal covert operations, with heavy reliance placed upon those performed by regional Sunni allies. By empowering jihadis as proxies, President Obama has borrowed much from the Reagan administration’s Afghan playbook. As he signaled the launch of this campaign in August 2011, President Obama served notice that the United States would be “pressuring President Assad to step aside”. But one year later, a Defence Intelligence Agency report revealed a hitherto unacknowledged sectarian war goal: the establishment of a “declared or undeclared Salafist Principality in eastern Syria”. It geo-political function would be to break the Shiite crescent. As of today, this hybrid war has produced not just one, but a conglomeration of religiously cleansed Sunni Islamist principalities in northern and eastern Syria. Some are controlled by the Islamic State and al-Qaida, while others are dominated by so-called moderate armies and militias. Among the latter are Washington-backed jihadist formations, such as Jaish al-Fateh and Jaish al-Islam. In all of these principalities, social pluralism has been replaced by Sunni supremacism, impacting not only religious minorities, but also non-Islamist, secular Sunni Muslims. This presentation will demonstrate the relationship between the dynamics of Washington’s hybrid war in Syria and the process of religious cleansing and the dismantling of state structures that support social pluralism.

Episode Information

Series
Changing Character of War
People
John Eibner
Keywords
war
conflict
Arab Spring
syria
middle east
Department: Pembroke College
Date Added: 05/04/2017
Duration:

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Dr Fiona Godlee

Series
Trust the Evidence
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Professor Carl Heneghan, Director of the Centre for Evidence-Based Medicine, in conversation with Dr Fiona Godlee, Editor-in-Chief of The British Medical Journal (BMJ).
Trust the Evidence is a new podcast series presenting conversations with individuals interested in improving healthcare through the use of better evidence.

Episode Information

Series
Trust the Evidence
People
Fiona Godlee
Carl Heneghan
Keywords
Medicine
Health
evidence based medicine
Department: Centre for Evidence-Based Medicine
Date Added: 05/04/2017
Duration: 00:11:23

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The New Era in Observational Cosmology

Series
The Physics of Fine-Tuning
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In the fourth part of their discussion, Pedro Ferreira and Jerome Martin conjecture about the future of inflation. They talk about the potential for new evidence for and against the theory, and the variety of new probes into our cosmological environment.
This discussion was conducted at the University of Oxford on March 15, 2017.

Episode Information

Series
The Physics of Fine-Tuning
People
Pedro Ferreira
Jerome Martin
Keywords
fine-tuning
Physics
cosmology
philosophy of physics
inflation
gravity waves
Department: Department of Physics
Date Added: 04/04/2017
Duration: 00:07:17

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When is a theory good enough?

Series
The Physics of Fine-Tuning
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In the third part of their discussion, Pedro Ferreira and Jerome Martin talk about whether one should look for a deeper physical theory when one’s current theory is well-supported by observation.
They discuss the rise of inflationary theory, its alternatives, and our expectations for future physics. This discussion was conducted at the University of Oxford on March 15, 2017.

Episode Information

Series
The Physics of Fine-Tuning
People
Pedro Ferreira
Jerome Martin
Keywords
fine-tuning
Physics
cosmology
philosophy of physics
inflation
Department: Department of Physics
Date Added: 04/04/2017
Duration: 00:14:10

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Can we measure naturalness?

Series
The Physics of Fine-Tuning
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In the second part of their discussion, Pedro Ferreira and Jerome Martin consider ways to build the naturalness of an inflationary model into our expectations for observing it.
They debate the feasibility of measuring the degree to which an inflationary model is inspired by considerations from other parts of physics, and describe the applicability of Bayesian methods when we have background knowledge. This discussion was conducted at the University of Oxford on March 15, 2017.

Episode Information

Series
The Physics of Fine-Tuning
People
Pedro Ferreira
Jerome Martin
Keywords
fine-tuning
Physics
cosmology
philosophy of physics
inflation
bayesian statistics
Department: Department of Physics
Date Added: 04/04/2017
Duration: 00:07:46

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An Encyclopedia of Inflation

Series
The Physics of Fine-Tuning
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In the first part of their discussion, Pedro Ferreira and Jerome Martin talk about the variety of inflationary models. They discuss methods for distinguishing between them based on evidence and describe the application of Bayesian statistics to inflation.
This discussion was conducted at the University of Oxford on March 15, 2017.


Episode Information

Series
The Physics of Fine-Tuning
People
Pedro Ferreira
Jerome Martin
Keywords
fine-tuning
Physics
cosmology
philosophy of physics
inflation
bayesian statistics
Department: Department of Physics
Date Added: 04/04/2017
Duration: 00:24:12

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Inflation in the Future

Series
The Physics of Fine-Tuning
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What should we expect to learn in the future? In the fourth part of their chat, Dave Sloan and Robert Brandenberger talk about how we expect inflationary theory to develop, and how observations may lead to new physics in this area.

Episode Information

Series
The Physics of Fine-Tuning
People
David Sloan
Robert Brandenberger
Keywords
fine-tuning
Physics
science
philosophy of science
astronomy
inflation
cosmology
quantum gravity
Department: Department of Physics
Date Added: 04/04/2017
Duration: 00:07:03

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