Last Updated on January 15, 2023
In physics, string theory is a theoretical framework in which the point-like particles of particle physics are replaced by one-dimensional objects called strings. String theory describes how these strings propagate through space and interact with each other.
On distance scales larger than the string scale, a string looks just like an ordinary particle, with its mass, charge, and other properties determined by the vibrational state of the string. In string theory, one of the many vibrational states of the string corresponds to the graviton, a quantum mechanical particle that carries the gravitational force. Thus, string theory is a theory of quantum gravity.
Right here on infolearners, you are privy to a litany of relevant information on string theory overview, top physics research institutes in the world, best nuclear physics schools, best universities for theoretical physics, and so much more. Take out time to visit our catalog for more information on similar topics.
String Theory Overview
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.
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 anti-de Sitter/conformal field theory correspondence (AdS/CFT correspondence), which relates string theory to another type of physical theory called a quantum field theory.
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.
Best Schools For String Theory
| Rank | School name |
|---|---|
| #1 | Princeton University(Princeton, NJ, US) |
| #2 | Harvard University(Cambridge, MA, US) |
| #3 | Stanford University(Stanford, CA, US) |
| #4 | University of California—Berkeley(Berkeley, CA, US) |
| #5 | Massachusetts Institute of Technology(Cambridge, MA, US) |
| #6 | California Institute of Technology(Pasadena, CA, US) |
| #7 | University of California—Santa Barbara(Santa Barbara, CA, US) |
| #8 | University of Chicago(Chicago, IL, US) |
| #9 | Cornell University(Ithaca, NY, US) |
| #10 | Columbia University(New York, NY, US) |
| #11 | University of Michigan—Ann Arbor(Ann Arbor, MI, US) |
| #11 | University of Wisconsin—Madison(Madison, WI, US) |
| #13 | Yale University(New Haven, CT, US) |
| #14 | University of California—Los Angeles(Los Angeles, CA, US) |
Top physics research institutes in the world
1. Chinese Academy of Sciences
Fractional count*: 534.99 (2.0%)†, Article count‡: 1,826
The world’s largest research organization, the Chinese Academy of Sciences (CAS) has retained first place in this category for four consecutive years as the number one producer of high-quality research in the physical sciences, as tracked by the Nature Index.
“The size of our research body determines CAS’s top position,” says Liu Wuming, a leading physicist at the CAS Institute of Physics. According to Liu, the institute has a team of more than 2,000 researchers — 10 times of that of universities with leading physics research, such as the University of California, Berkeley.
“More importantly,” adds Liu, “we have stable funding to support long-term research, such as in superconductivity. In Western universities, professors often have to pursue grants that are in ‘hot’ areas at the time.”
2. Max Planck Society
Fractional count: 310.15 (−1.6%), Article count: 1,033
Named after the Nobel prize-winning creator of quantum theory, the Max Planck Society’s strength in physical sciences began in the first half of last century. Today, it maintains second position in the top 10 for the third consecutive year.Nature Index 2019 Annual Tables
The German powerhouse is an international team player, with foreign institutions accounting for more than 70% of its research partnerships. The Max Planck-Princeton Research Center for Plasma Physics facilitates research collaboration between physicists in Germany and the United States. Founded in 2012, the group seeks to answer questions in magnetic reconnection, energetic particles and plasma turbulence.
In 2018, Max Planck researchers were part of a large global team that observed the creation of a neutron star binary system for the first time. The Science paper was covered by more than 30 news outlets.
3. French National Centre for Scientific Research
Fractional count 242.70 (−13.6%), Article count: 1,461
Ranked in the top 10 research institutions in the 2019 Nature Index Annual Tables, as well as appearing in the top 10s for government institution, chemistry, Earth and environmental sciences, and physical sciences, the French National Centre for Scientific Research (CNRS) is a global leader in multidisciplinary research and fundamental science.
Its physics research is split between the Institute of Physics in Paris and the National Institute of Nuclear and Particle Physics, which encompasses several labs housed by universities across France.
High-profile CNRS physicists include Alain Brillet and Thibault Damour, who were part of the team that achieved the first detection of gravitational waves in 2016, and were joint winners of the 2017 CNRS Gold Medal — the highest French scientific distinction. Damour played a role both in the indirect detection of gravitational waves in the 1980s, and in their direct detection more than three decades later.
4. Massachusetts Institute of Technology
Fractional count 223.34 (3.2%), Article count: 625
Soon after establishing the Massachusetts Institute of Technology (MIT) in 1861, its founder, William Barton Rogers, said that students of physics would be called on “to execute with their own hands various experiments in mechanics, pneumatics, sound, optics, electricity, and other branches of experimental physics”. This hands-on approach, revolutionary at the time, is now common in institutions the world over. It has seen MIT physicists push the boundaries of knowledge of space, time, matter and energy.
The Department of Physics has 75 faculty members, 280 undergraduate majors, and 245 graduate students. Some are currently teamed up with researchers at the Charles Stark Draper Laboratory, also in Cambridge, Massachusetts, to develop a new space boot with built-in vibrating sensors and motors to guide the wearer around obstacles.
In 2017, notable MIT physicist, Rainer Weiss, won the Nobel Prize in Physics with collaborators Kip Thorne and Barry Barish at the California Institute of Technology for their observation of gravitational waves and contributions to the Laser Interferometer Gravitational-Wave Observatory (LIGO) detector.
5. Stanford University
Fractional count: 218.87 (2.5%), Article count: 521
One of the founding departments at Stanford University, the physical sciences quickly became one of the university’s strongest disciplines, thanks largely to its first professor of theoretical physics, Felix Bloch, who would go on to make transformative discoveries in electron transport, ferromagnetism and nuclear magnetic resonance.
The Stanford Linear Accelerator Center’s (SLAC) particle accelerator, running since 1967, now houses the world’s most powerful X-ray free-electron laser. More than 2,700 scientists from around the world use the lab’s facilities each year, and more than 700 scientific papers are published annually based on research at SLAC.
Notable physics alumni include Sally Ride, the first American woman in space, and Richard Taylor, who was among the recipients of the 1990 Nobel prize for the discovery of quarks.
Best universities for theoretical physics
1. Massachusetts Institute of Technology (MIT)
Cambridge, Massachusetts
Many consider MIT to be the world’s leading science school. Located near other leading institutions, such as Harvard, MIT enjoys many collaborative research opportunities. Since the school’s founding in 1861, students have been exploring the field of physics through hands-on learning experiences. Offering some of the best undergraduate physics programs in the U.S., MIT’s Department of Physics has seen four Nobel Prize recipients and seven Oersted Medal recipients since 1990.
The physics department prides itself on its outreach efforts to underrepresented minorities and first-generation college students through its Summer Research Program and Physics Bridge Program. Learners who participate in these initiatives emerge as stronger candidates for the school’s graduate physics programs. MIT’s physics department works with 16 affiliated labs and centers , such as:
- The Haystack Radio Observatory
- The Laser Interferometer Gravitational Wave Observatory
- The Kavli Institute for Astrophysics and Space Research
- The Research Laboratory of Electronics
- The Plasma Science and Fusion Center
2. Harvard University
Cambridge, Massachusetts
Harvard’s Department of Physics has offered some of the best undergraduate physics programs since 1642.
Harvard also hosts the Jefferson Laboratory, the oldest physics lab in the U.S. Members of the department have received recognition for work in high-pressure physics, the invention of the separated oscillatory fields method, and the development of new methods for nuclear magnetic precision measurements. In total, the department can claims 10 Nobel Prize recipients.
Harvard’s campus hosts eight research centers:
- The Center for Ultracold Atoms
- The Center for Nanoscale Systems
- The Harvard-Smithsonian Center for Astrophysics
- The Institute for Theoretical Atomic, Molecular, and Optical Physics
- The Laboratory for Particle Physics and Cosmology
- The Minerals Research Science and Engineering Center
- The Rowland Institute
In addition, the school’s faculty and students have developed research relationships with:
- The Fermi National Accelerator Laboratory
- CERN
- The Cornell Wilson Synchrotron Laboratory
- The Stanford Linear Accelerator Center
- The Lawrence Livermore National Lab
- The Soudan Mines in Northern Minnesota
- The National Institute of Standards and Technology
3. University of Cambridge
Cambridge, England
By 1642, the study of theoretical and mathematical physics was available at Cambridge. In 1874, the Cavendish Laboratory opened, fostering the school’s first explorations of applied physics with some of the best physics programs available at that time. Past contributors to Cambridge’s Department of Physics include Ernest Rutherford, the father of nuclear physics, and Niels Bohr, who studied the structure and function of the atom. The discovery of the neutron, the first splitting of the atom, and the discovery of antimatter are also attributable to Cambridge professors and students. A total of 20 Nobel Prize in Physics recipient are associated with the university. The Cambridge physics department has several ongoing research programs like the Centre for Scientific Computing Collaboration, the Winton Programme for the Physics of Sustainability, and the Centre for the Physics of Medicine.
4. Stanford University
Stanford, California
Stanford’s Physics Department was among the first to open after the university’s founding in 1891.
In 1934, Swiss physicist Felix Bloch began work at Stanford. He brought with him his theory of electron transport and ferromagnetism, the Bethe-Bloch equation, and his discovery of spin waves and Bloch walls. Recently, Stanford physicists played a key role in monitoring and analyzing the brightest gamma ray burst ever measured.
Offerings some of the best undergraduate physics programs in the U.S., the Stanford holds a record for three consecutive Nobel Prize recipients: Professor Robert Laughlin in 1998, Professor Steven Chu in 1997, and Professor Douglas Osheroff in 1996. A total of 18 Nobel Prize recipients associate with the school. Research centers affiliated with Stanford’s department of physics include:
- The Geballe Laboratory for Advanced Materials
- L. Ginzton Laboratory
- the Picosecond Free Electron Laser Center
- The W. W. Hansen Experimental Physics Laboratory
- The Kavli Institute for Particle Astrophysics and Cosmology
- The PULSE Institute for Ultrafast Energy Science
- The Institute for Materials and Energy Sciences
- The Institute for Theoretical Physics
5. University of California – Berkeley
Berkeley, California
Berkeley’s Department of Physics operates within the College of Letters and Science. Approximately one-third of the Nobel Prize recipients associated with Berkeley come from the physics department; these recipients include nine full-time faculty members and seven alumni. The numerous achievements of past and present department members include the invention of the cyclotron, the invention of the bubble chamber, and the discovery of the accelerating expansion of the universe.
Unlike many other physics Ph.D. programs, Berkeley does not require its doctoral students to participate in dissertation defenses; instead, these students must prove effective research skills to peers and faculty through other means. Available research topics cover the full range of theoretical and experimental physics , such as:
- Astrophysics and cosmology
- Molecular and Optical Physics
- Condensed Matter
- Elementary Particles and Fields
- Fusion and Plasma
- Low-temperature Physics
Berkeley’s Department of Physics maintains research partnerships with the Lawrence Berkeley National Laboratory, the Space Sciences Laboratory, and the Molecular Design Institute. Students have access to a total of eight science libraries on campus; these libraries include the Physics-Astronomy Library.
