String theory was once the hottest topic in physics. In the 80s and 90s, string theory promised to unlock all the limits of reality. Stemming from the idea that matter and energy are made up of microscopic, constantly vibrating strings rather than collections of particles, string theory aspires to tie all the forces we know into a single force. neat package. Many physicists nod their heads that string theory can become the theory of everything. Those who believe in string theory will have to believe in the torchbearer who leads the way with the desire to bring string theory to light.
Andrew Strominger, a physicist now at Harvard University, is the torchbearer you’re looking for; he spent decades studying string theory and still remembers the enthusiasm of his early days. “At the famous moment when [string theory] was just coming out, it was claimed that we had solved all the problems of physics and had the final theory in our hands,” recalls Strominger.
Andrew Strominger.
He knew that, even during the social boom of the 1980s (in terms of both popular culture and scientific discovery), the claim was still an exaggeration. As a matter of course (and as with many other scientific breakthroughs), a growing number of criticisms, reviews, and attacks on string theory have emerged throughout the early days to the present. At this point, no one has yet created an experiment to prove or disprove the existence of microscopic strings.
The strongest reaction probably came in 2006, when a series of critically acclaimed books and opinion pieces attacked string theory. Today, string theory is no longer enjoying its full glory, but it has not left the physics stage and is still lingering.
“ String theory is evolving and getting better – we understand it better every day, ” said Juan Maldacena, a scientist at the Institute for Advanced Study at Princeton, who still believes in string theory.
Are our fates bound by a tangle of strings?
At the present time, many string theorists are inclined to think that strings have practical applications, no longer claiming that string theory has the potential to explain everything but focus on studying things. exist at this moment. Some people are using string theory to solve problems in pure mathematics*, while Professor Strominger is trying to use string theory to complete the concept of a cosmic black hole. Many others are relying on string theory to perform calculations involving particle physics and unknown states of matter.
All of these efforts have one thing in common. As Professor Strominger points out, string theory may not be the theory of everything, but it is “certainly a theory of something”.
Strominger isn’t the type to follow a rut. He dropped out of Harvard twice in the 1970s, lived for a while in small communities in the US and China, before returning to school; This time, he is determined to explore the universe through physical factors that are only theoretical. As an MIT graduate, Strominger was advised to avoid unsettled concepts, such as string theory. Strominger shook his head and chose his own path.
And his gamble paid off. In 1995, three years after holding his doctorate, Strominger became a co-author on a series of important studies, scientific reports that would later come to be known as the “first string revolution”.
The central concept of string theory revolves around the fact that strings, considered by string theory to be the most fundamental unit of nature, vibrate in a Universe of between 10 and 11 dimensions. The three dimensions of space we know and the flow of time will create a fourth dimension, which means that there must be 6-7 other dimensions hidden somewhere, perhaps they shrink so small that we can’t see them. can be seen in the usual way.
Tiny dimensions must be compressed in specific ways to produce the physical effect we’re seeing, and Strominger and colleagues suggest that Calabi-Yau space, a mathematical object that exists in space 6 dimensions, will represent the compression of those special dimensions. The mass of a particle, the strength of a force or any other fundamental measure will depend on the geometry of this multidimensional space.
The 2D section of the Calabi-Yau space exists in a 6-dimensional space.
Not long after the conception of the “Calabi-Yau space” , string theorists made a new discovery. By rotating the Calabi-Yau space in a special way, they were able to create a kind of mirror image despite the two different shapes. What surprised the scientists was that it seemed that the two Calabi-Yau shapes had some hidden relationship, and together they made up a kind of physics. Theoreticians call this phenomenon “ mirror symmetry ”.
Scientists quickly realized the potential of the strange phenomenon: they could use it to successfully solve many math puzzles that have plagued the brains but the most brilliant minds in history. In 1991, physicist Philip Candelas and his colleagues used reflection symmetry to solve the centenary problem, thereby counting the number of spheres that could fit into a Calabi-Yau space.
Mathematician, seeing the fertile ground that Calabi-Yau space opens up, immediately tried to apply reflection symmetry to solve problems listed in geometry, mostly counting the number of segments and current curves. present in complex surfaces and in three-dimensional spaces. Reflective symmetry has injected new life into the field of spatial geometry, and research is still underway, with greater determination than ever before.
“ Over the years, progress has been made to condense this idea into a single complex formula. The geometrical, arithmetical and physical aspects of reflection symmetry are starting to come together ,” said Mathematician Bong Lian of Brandeis University.
Although Strominger is one of the authors who used mathematics to write a report explaining how reflection symmetry works, in the past two decades he has used string theory to study cosmic black holes. Strominger and Cumrun Vafa work together to investigate a puzzling discovery made in the 1970s by two physicists, Jacob Bekenstein and Stephen Hawking.
Stephen Hawking and Jacob Beckenstein.
Until this point, scientists still thought that a black hole was a simple object – essentially just a hole in space, described with only three factors: mass, the way it rotates, and volume. its electricity. Using general relativity, quantum theory, and thermodynamics, Bekenstein and Hawking wrote the formula showing that black holes contain an unexpectedly high amount of entropy, meaning that there are many ways to arrange particles inside the hole. black.
In other words, the structure inside a black hole is incredibly complex and can exist in many different possible states. The Bekenstein-Hawking formula calculates a specific number of entropy, determining the states inside the black hole without specifying what that state is.
In 1996, Strominger and Vafa used string theory to explain the microscopic elements of black holes. Their approach to getting a look inside a black hole (and like Professor Candelas’ approach) is similar to counting the number of spheres that fit in Calabi-Yau space. The results obtained by Strominger and Vafa are in perfect agreement with the results of Bekenstein and Hawking. This is a great achievement that string theory has achieved, because it can allow us to look inside a black hole, something no theory has been able to do so far.
Cumrun Vafa and Andrew Strominger.
Strominger continued to deepen his research. His work with Professor Vafa shows that a rapidly rotating black hole has “conformal symmetry” , i.e. the size of the black hole does not affect some of its properties, some The “angle” of the black hole remains the same even if the distance between the two points changes.
Professor Strominger gradually realized that the existence of this undiscovered symmetry could underlie a range of predictions. For example, he and his collaborators tried to calculate the intensity of electromagnetic radiation emitted from the region of space near the black hole. When science completes the Event Horizon Telescope array, he says, astronomers can make measurements to determine if those radiation estimates are correct.
Mankind’s first image of a black hole was taken with the Event Horizon Telescope.
Using similar techniques (which are formed by string theory), Strominger’s team calculated the spectrum of gravitational waves produced when an object (such as stars) falls into a black hole. Similar to what will happen with the radiation estimate above, science will get the answer when it successfully builds the Advanced Laser Interferometer Space Antenna. Even the Laser Interferometer Gravitational Wave Observatory (LIGO – the system that detected gravitational waves) could contribute to the research.
Soon, astronomers will be inundated with data without having time to analyze it all. ” We want to use ideas from string theory to explore this array .”
Meanwhile, other physicists are applying methodologies born of string theory to study the extreme states of matter, from the superheated plasmas that form in particle accelerators to the denser materials. synthesized in the laboratory at a cold near absolute zero.
Researcher Andrew Green from University College London, who specializes in studying strange states of matter that occur at extremely low temperatures, never thought he would be immersed in string theory, but then he found it too. Well worth the time to research. Even though it failed to find the essence of the world through the thin strings, he said that ” it has accelerated the development of a new set of mathematical techniques that are applicable to many areas of physics “.
Many of these approaches are directly related to spatial geometry, more than 3 dimensions. In the words of physicist Green, it “allows you to draw geometrical drawings that were previously expressed as arithmetic formulas”. Green called string theory ” the new calculus ,” and that the ideas derived from string theory would soon become the norm in theoretical physics.
Professor Strominger also agrees with the above statement. Although string theory is not something that binds all aspects of physics into a unified theory, he still sees string theory as the starting point from which a theory of everything can take shape. Through experimentation, we immediately see that string theory is a powerful tool for fitting things that seem impossible to fit together. The more we see more and more new applications of string theory, it becomes clear that this is not a trivial thing, but can become the key to decipher multidimensional space.