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Steven Weinberg in conversation with Andrew Strominger

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Steven Weinberg is a professor of physics and astronomy at the University of Texas at Austin. His research on elementary particle physics and cosmology has been honored with the Nobel Prize in Physics, the National Medal of Science, the Benjamin Franklin Medal of the American Philosophical Society, the Dannie Heinemann Prize for Mathematical Physics, and numerous other awards. He has written over 300 scientific articles, and six treatises on general relativity, quantum field theory, cosmology, and quantum mechanics. Among his books for general readers are Dreams of a Final Theory and The First Three Minutes, and two collections of published essays, Facing Up: Science and its Cultural Adversaries, and Lake Views: This World and the Universe.

Andrew Strominger is the Gwill E. York Professor of Physics at Harvard University and a founding member of the Black Hole Initiative. He is a renowned theoretical physicist who has made pathbreaking contributions to classical and quantum gravity, quantum field theory and string theory. In recognition of his accomplishments, Strominger has been awarded the prestigious 2017 Breakthrough Prize in Fundamental Physics, the 2016 Dannie Heineman Prize from the American Physical Society, and numerous other honors.

Written by physicsgg

April 6, 2021 at 11:50 am

Why is AI hard and Physics simple?

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We discuss why AI is hard and why physics is simple. We discuss how physical intuition and the approach of theoretical physics can be brought to bear on the field of artificial intelligence and specifically machine learning. We suggest that the underlying project of machine learning and the underlying project of physics are strongly coupled through the principle of sparsity, and we call upon theoretical physicists to work on AI as physicists. As a first step in that direction, we discuss an upcoming book on the principles of deep learning theory that attempts to realize this approach…. Read more at

Written by physicsgg

April 2, 2021 at 12:11 pm

The quest for the proton charge radius

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A slight anomaly in optical spectra of the hydrogen atom led Willis E. Lamb to the search for the proton size. As a result, he found the shift of the 2S1/2 level, the first experimental demonstration of quantum electrodynamics. In return, a modern test of QED yielded a new value of the charge radius of the proton. This sounds like Baron Muenchausens tale: to pull oneself out from the marsh by seizing his own hair. An independent method was necessary. Muonic hydrogen spectroscopy came to the aid. However, the high-precision result significantly differed from the previous, electronic, values: this is the proton radius puzzle. This puzzle produced a decade-long activity both in experimental work and in theory. Even if the puzzle seems to be solved, the precise determination of the proton charge radius requires further efforts in the future.

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Click to access 2103.17101v1.pdf

Written by physicsgg

April 2, 2021 at 8:11 am

How (and why) to raise e to the power of a matrix

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Written by physicsgg

April 1, 2021 at 6:49 pm

Posted in MATHEMATICS

An Analysis of the Concept of Inertial Frame

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The concept of inertial frame of reference is analysed. It has been shown that this fundamental concept of physics is not clear enough. A definition of inertial frame of reference is proposed which expresses its key inherent property. The definition is operational and powerful. Many other properties of inertial frames follow from the definition or it makes them plausible. In particular, the definition shows why physical laws obey space and time symmetries and the principle of relativity, it resolves the problem of clock synchronization and the role of light in it, as well as the problem of the geometry of inertial frames.
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Click to access 2103.15570.pdf

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March 31, 2021 at 8:56 am

James D. Bjorken:“Why Do We Do Physics? Because Physics Is Fun!”

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In this informal memoir, the author describes his passage through a golden age of elementary particle physics. It includes not only his career trajectory as a theoretical physicist but also his excursions into experimental physics and particle accelerator theory. While his successes are highlighted, some unsuccessful efforts are included in the narrative as well. Those “losers” were arguably as pleasurable as the less-frequent “winners.” Since retirement, the author has become interested in gravitation theory and cosmology—a new golden age. This activity is also briefly described ….. Read more at: https://www.annualreviews.org/doi/full/10.1146/annurev-nucl-101918-023359

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March 30, 2021 at 3:14 pm

MAGIS-100: The quantum search for dark matter and gravitational waves

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Written by physicsgg

March 18, 2021 at 9:20 pm

Posted in DARK MATTER

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Reality as a Vector in Hilbert Space

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Sean M. Carroll
I defend the extremist position that the fundamental ontology of the world consists of a vector in Hilbert space evolving according to the Schrödinger equation. The laws of physics are determined solely by the energy eigenspectrum of the Hamiltonian. The structure of our observed world, including space and fields living within it, should arise as a higher-level emergent description. I sketch how this might come about, although much work remains to be done.
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Click to access 2103.09780.pdf

Written by physicsgg

March 18, 2021 at 12:36 pm