Attempts to unify general relativity and quantum mechanics date back to the 1940s. As Michio Kaku calls the "God equation," which contains all the major laws of physics, including quantum mechanics and general relativity, is the ultimate mathematical formula for explaining every physical phenomenon in the universe. Sounds appealing, doesn't it?
The 1990 Fields Medal, the most prestigious award in the field of pure mathematics, was awarded to a theoretical physicist, Edward Witten. Dr. Edward Witten was the first physicist to be awarded the medal by the International Mathematical Union for his demonstration of the positive energy theorem in general relativity in 1981. He was one of the most important figures in the development of general relativity and the unified theory of quantum mechanics (commonly known as superstring theory).
Paul Dirac (right) and Edward Witten discuss.
For more than 30 years, Witten, as a leader in superstring theory, has made significant contributions to theoretical physics and pure mathematics, and has promoted the development of mathematics, prompting many mathematicians to carry out cutting-edge research. Witten has been researching and has made crucial contributions in several areas of mathematical physics, including string theory, quantum gravity, and supersymmetric quantum field theory. Witten set off a trend in the physics community, just as Van Gogh set off a trend in the field of art, and promoted the development of mathematics and physics by applying his physical intuition and mathematical skills. As Samuel Trieman put it in The New York Times magazine (The Theory of Everything, published in 1987):
We shouldn't compare Einstein too often, but when it comes to Witten, he's far more than anyone else. He put a group of people on a new path. He offers elegant, breathtaking proofs...
Witten was born on August 26, 1951 in Baltimore, Maryland, the son of Louis Witten, a theoretical physicist specializing in gravity and general relativity. Witten attended Baltimore Park School, and unlike other physicists, he received a Bachelor of Arts degree from Brandeis University in 1971 with a major in History and a minor in Linguistics. With a keen interest in linguistics, Witten also had ambitions for politics. After graduation, he also worked for George McGovern's presidential campaign.
Witten then studied economics at the University of Wisconsin-Madison, but dropped out after completing a semester and studied applied mathematics at Princeton In 1973, before receiving a Ph.D. in physics in 1976 under the direction of theoretical physicist and 2004 Nobel laureate in physics, David Gross, completing a ph.D. in the short distance analysis titled "Some problems in the short distance analysis of normative theory." of gauge theories) "papers.
David Gross, Stephen Hawking and Edward Witten at the "Strings 2001" International Conference at the Tata Institute of Basic Sciences in Mumbai, India.
Most people who have not been trained in physics may think that the work of a physicist is an extremely complex computational problem, but this is not the essence of it. The essence of it is that physics is about concepts, and it is about wanting to understand concepts, the principles of how the world works. —Edward Witten.
Witten is considered the father of modern string theory for his unparalleled contribution to the mathematical development of the theory. But what exactly was Witten's contribution to this fascinating new field of physics, daring him to reconcile general relativity and quantum mechanics? In the early 1970s, when physicists were looking for ways to incorporate fermions into the string theory lineage, this led to the proposal of supersymmetry, a mathematical model of the transformation from bosons and fermions. In this way, it led to the invention of a new theory (now called superstring theory), essentially a string theory that included fermion vibrations.
But the path to developing this new theory is not as easy as it seems. By the mid-20th century, theoretical and mathematical physicists had developed five different versions of string theory, unable to figure out exactly which one was the real string theory. These five different versions of the theory are called type I, type IIA, type IIB, and two types of hybrid string theory (SO(32) and E8xE8. The biggest problem is to determine which theory is the actual theory of everything, and which the low-energy limits of that theory coincide with the physical phenomena observed today. In the spring of 1995, Dr. Witten, speaking at the University of California's String Theory Conference, offered a surprising insight into the solution of the problem, which later began the second superstring revolution in physics. He said that the five theories are not actually completely different, but rather different limits of one theory. He unified all five theories to form a new main theory called M-theory. Professor Brian Green quotes in his best-selling book The Structure of the Universe (2003):
Spring 1995... Drawing on the research of a number of string theorists (including Chris Hull, Paul Townsend, Ashuk-Sen, Michael Duff, John Schwartz, and many others), Edward Witten, the world's most famous string theorist for decades, discovered a hidden unity that linked all five string theories. Witten shows that these five theories are not distinct, but are really just mathematical analysis of one theory in five different ways. This unified main theory is tentatively called M-theory.
Superstring theory is considered by many great intellectuals in modern science to be the most promising candidate theory for the theory of everything. However, the theory has its own limitations. Superstring theory is based on supersymmetry, and so far no such supersymmetric particles have been found. So, basically, the lack of experimental evidence is a serious limitation on the theory, although it is theoretically accurate and mathematically very consistent.
The beginning of the concept of replacing point-like particles with vibrating strings dates back to the 1960s. String theory predicts a particle with a mass of zero and a spin of 2. Two mathematical physicists, John Schwartz and Joel Schäcker, discovered in 1974 that such particles are gravitons, quantum carriers of gravity. This creates an extremely astonishing way out for reconciling gravity and quantum mechanics.
The greatest intellectual stimulation of my life.
Witten is considered one of the greatest living physicists today. Many physicists believe he was the true successor to Einstein. In a 2014 article in Scientific American, John Hogan mentioned him:
At a cosmological conference in 1990, I asked attendees (including Hawking, Michael Turner, James Peebles, Alan Gus, and Andre Lind, among others) to nominate the smartest living physicists. Edward Witten got the most votes.
In addition to the Fields Medal, Witten has received many awards such as the National Science Prize (2002) and the Breakthrough Prize in Fundamental Physics (2012). He was appointed a Fellow of the Holy See Academy of Sciences in 2006 and a Fellow of the American Mathematical Society in 2012. Despite many criticisms of the theory and uncertainty about its experimental evidence, Dr. Witten believes that string theory may be the ultimate theory of everything and is still working to provide new insights into the theory.