Modern understanding of the ultimate constituents of matter
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These elementary particles interact via various kinds
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These forces give rise to complicated interaction between elementary particles
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For examples
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Result
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For developing a theory of elementary particles and their forces, we must remember two important points:
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There is a mathematical theory, known as the standard model,
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List of elementary particles according to the 'standard model'
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Despite these successes, the standard model cannot be the final story.
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However these can be explained by minor modifications of the standard model without giving up of any of the basic principles
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However, even with these modifications standard model will not be complete
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Can we modify the standard model so as to include gravity?
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The first step - making gravity consistent with special theory of relativity
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The big
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Cosmology
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Since an expanding radiation cools, the obvious conclusion is that the universe was hotter in the past.
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When the universe was very hot, it was filled with very energetic elementary particles colliding with each other
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However since we know that the standard model is not the complete story about elementary particles
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There is another big puzzle in cosmology
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For example
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The radiation originated
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A possible answer: Inflation
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What is responsible for such a rapid expansion of the universe?
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Moving forward....
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Summary of main points so far:
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Since gravity is so difficult to incorporate
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Basic ingredients of the standard model and its modifications
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Basic postulate of String Theory
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Typical size os a string ~ 10-33 cm
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It turns out that one of the vibrational states of the string acts as the mediator of gravitational force
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Furthermore the requirement of mathematical consistency completely fixes the underlying laws of string theory
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The uniqueness of string theory
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Summary
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Q/A
Description:
Embark on a captivating journey through the cosmos in this 1-hour 34-minute lecture by renowned physicist Ashoke Sen, part of the "Kaapi with Kuriosity" public lecture series. Explore the fascinating realms of elementary particle physics and cosmology, delving into the smallest constituents of matter and the grandest structures of the universe. Discover the Standard Model of particle physics, its successes and limitations, and the challenges of incorporating gravity into a unified theory. Unravel the mysteries of the universe's origins, including the concept of cosmic inflation and the puzzles of dark matter and dark energy. Learn about string theory as a potential framework for unifying all fundamental forces. Engage with complex scientific concepts presented in an accessible manner, suitable for curious minds from high school students to working professionals, and participate in an enlightening Q&A session to further satisfy your scientific curiosity.