string theory

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neufer
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string theory

Post by neufer » Fri Nov 29, 2019 10:01 pm

https://www.youtube.com/watch?v=25haxRuZQUk wrote:
Click to play embedded YouTube video.
Click to play embedded YouTube video.
.
<<(September 20, 2010) Leonard Susskind gives a lecture on the string theory and particle physics. He is a world renown theoretical physicist and uses graphs to help demonstrate the theories he is presenting.

String theory (with its close relative, M-theory) is the basis for the most ambitious theories of the physical world. It has profoundly influenced our understanding of gravity, cosmology, and particle physics. In this course we will develop the basic theoretical and mathematical ideas, including the string-theoretic origin of gravity, the theory of extra dimensions of space, the connection between strings and black holes, the "landscape" of string theory, and the holographic principle.>>
Art Neuendorffer

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neufer
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Re: string theory

Post by neufer » Sun Dec 01, 2019 4:51 pm

Click to play embedded YouTube video.
Click to play embedded YouTube video.
Art Neuendorffer

Marsdmitri
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Re: string theory

Post by Marsdmitri » Tue Dec 01, 2020 8:09 am

For 40 years, this theory, like astrology, has not predicted anything new and has not discovered any new facts in nature. This mathematics is almost unrelated to physics, nature. It’s only useful for mathematicians to get a place of professor at the university. If it weren’t there, no one would notice. Look please this article https://arxiv.org/abs/physics/0102051
and one book:
L. Smolin,The trouble with physics: The rise of string theory, the fall of a science, and what comes next, Mariner books, 2007.

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neufer
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Re: string theory

Post by neufer » Wed Dec 02, 2020 9:58 pm

Marsdmitri wrote:
Tue Dec 01, 2020 8:09 am

For 40 years, this theory, like astrology, has not predicted anything new and has not discovered any new facts in nature. This mathematics is almost unrelated to physics, nature. It’s only useful for mathematicians to get a place of professor at the university. If it weren’t there, no one would notice. Look please this article https://arxiv.org/abs/physics/0102051
and one book:

L. Smolin,The trouble with physics: The rise of string theory, the fall of a science, and what comes next, Mariner books, 2007.
Given time (and governmnt support):
  • 1) astrology led to astronomy,
    2) alchemy led to chemistry and
    3) folk remedies led to modern medicine.
https://en.wikipedia.org/wiki/String_theory wrote:
Click to play embedded YouTube video.

<<String theory was first studied in the late 1960s as a theory of the strong nuclear force, before being abandoned in favor of quantum chromodynamics. Subsequently, it was realized that the very properties that made string theory unsuitable as a theory of nuclear physics made it a promising candidate for a quantum theory of gravity. The earliest version of string theory, bosonic string theory, incorporated only the class of particles known as bosons. It later developed into superstring theory, which posits a connection called supersymmetry between bosons and the class of particles called fermions. Five consistent versions of superstring theory were developed before it was conjectured in the mid-1990s that they were all different limiting cases of a single theory in 11 dimensions known as M-theory. In late 1997, theorists discovered an important relationship called the AdS/CFT correspondence, which relates string theory to another type of physical theory called a quantum field theory.

String theory is a broad and varied subject that attempts to address a number of deep questions of fundamental physics. String theory has contributed a number of advances to mathematical physics, which have been applied to a variety of problems in black hole physics, early universe cosmology, nuclear physics, and condensed matter physics, and it has stimulated a number of major developments in pure mathematics. Because string theory potentially provides a unified description of gravity and particle physics, it is a candidate for a theory of everything, a self-contained mathematical model that describes all fundamental forces and forms of matter. Despite much work on these problems, it is not known to what extent string theory describes the real world or how much freedom the theory allows in the choice of its details.

One of the challenges of string theory is that the full theory does not have a satisfactory definition in all circumstances. Another issue is that the theory is thought to describe an enormous landscape of possible universes, which has complicated efforts to develop theories of particle physics based on string theory. These issues have led some in the community to criticize these approaches to physics, and to question the value of continued research on string theory unification.>>
  • The main trouble with physics is the demise of the Superconducting Super Collider (SSC) in 1993:
https://en.wikipedia.org/wiki/Superconducting_Super_Collider#Reactions_to_the_cancellation wrote:
<<During the design and the first construction stage, a heated debate ensued about the high cost of the Superconducting Super Collider (SSC) project. In 1987, Congress was told the project could be completed for $4.4 billion, and it gained the enthusiastic support of Speaker Jim Wright of nearby Fort Worth, Texas. A recurring argument was the contrast with NASA's contribution to the International Space Station (ISS), a similar dollar amount. Critics of the project (Congressmen representing other US states and scientists working in non-SSC fields who felt the money would be better spent on their own fields) argued that the US could not afford both of them.

Leaders hoped to get financial support from Europe, Canada, Japan, Russia, and India. This was hindered by promotion of the project as promoting American superiority. European funding remained at CERN, which was already working on the Large Hadron Collider. India pledged $50 million, but talks with Japan foundered over trade tensions in the automobile industry. A US-Japanese trade mission where SSC funding was supposed to be discussed ended in the George H. W. Bush vomiting incident.

Congress began appropriating annual funding for the project. In February, the General Accounting Office reported a $630 million overrun in the $1.25 billion construction budget. By March, the New York Times reported the estimated total cost had grown to $8.4 billion. In June, the non-profit Project on Government Oversight released a draft audit report by the Department of Energy's Inspector General heavily criticizing the Super Collider for its high costs and poor management by officials in charge of it.

In 1993, Clinton tried to prevent the cancellation by asking Congress to continue "to support this important and challenging effort" through completion because "abandoning the SSC at this point would signal that the United States is compromising its position of leadership in basic science". After $2 billion had been spent, the House of Representatives rejected funding on October 19, 1993, and Senate negotiators failed to restore it. Following Rep. Jim Slattery's successful orchestration in the House, President Clinton signed the bill that finally cancelled the project on October 30, 1993, stating regret at the "serious loss" for science.

Many factors contributed to the cancellation: rising cost estimates (to $12bn); poor management by physicists and Department of Energy officials; the end of the need to prove the supremacy of American science with the collapse of the Soviet Union and the end of the Cold War; belief that many smaller scientific experiments of equal merit could be funded for the same cost; Congress's desire to generally reduce spending (the United States was running a $255bn budget deficit); the reluctance of Texas Governor Ann Richards; and President Bill Clinton's initial lack of support for a project begun during the administrations of Richards's predecessor, Bill Clements, and Clinton's predecessors, Ronald Reagan and George H. W. Bush. The project's cancellation was also eased by opposition from within the scientific community. Prominent condensed matter physicists, such as Philip W. Anderson and Nicolaas Bloembergen, testified before Congress opposing the project. They argued that, although the SSC would certainly conduct high-quality research, it was not the only way to acquire new fundamental knowledge, as some of its supporters claimed, and so was unreasonably expensive. Scientific critics of the SSC pointed out that basic research in other areas, such as condensed matter physics and materials science, was underfunded compared to high energy physics, despite the fact that those fields were more likely to produce applications with technological and economic benefits.

Steven Weinberg, a Nobel laureate in Physics, places the cancellation of the SSC in the context of a bigger national and global socio-economic crisis, including a general crisis in funding for science research and for the provision of adequate education, healthcare, transportation and communication infrastructure, and criminal justice and law enforcement. Leon Lederman, a promoter and advocate from its early days, wrote his 1993 popular science book The God Particle: If the Universe Is the Answer, What Is the Question? – which sought to promote awareness of the significance of the work which necessitated such a project – in the context of the project's last years and loss of congressional support.>>
Art Neuendorffer