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Brane cosmology. Brane cosmology refers to several theories in particle physics and cosmology related to string theory, superstring theory and M-theory.

Brane cosmology

Brane and bulk[edit] The central idea is that the visible, four-dimensional universe is restricted to a brane inside a higher-dimensional space, called the "bulk" (also known as "hyperspace"). If the additional dimensions are compact, then the observed universe contains the extra dimensions, and then no reference to the bulk is appropriate. In the bulk model, at least some of the extra dimensions are extensive (possibly infinite), and other branes may be moving through this bulk.

Interactions with the bulk, and possibly with other branes, can influence our brane and thus introduce effects not seen in more standard cosmological models. Why gravity is weak and the cosmological constant is small[edit] Models of brane cosmology[edit] One of the earliest documented attempts to apply brane cosmology as part of a conceptual theory is dated to 1983.[5] Standing wave. Two opposing waves combine to form a standing wave.

Standing wave

For waves of equal amplitude traveling in opposing directions, there is on average no net propagation of energy. Moving medium[edit] As an example of the first type, under certain meteorological conditions standing waves form in the atmosphere in the lee of mountain ranges. Such waves are often exploited by glider pilots. Standing waves and hydraulic jumps also form on fast flowing river rapids and tidal currents such as the Saltstraumen maelstrom. Opposing waves[edit] In practice, losses in the transmission line and other components mean that a perfect reflection and a pure standing wave are never achieved.

Another example is standing waves in the open ocean formed by waves with the same wave period moving in opposite directions. Mathematical description[edit] In one dimension, two waves with the same frequency, wavelength and amplitude traveling in opposite directions will interfere and produce a standing wave or stationary wave. The Physics Classroom. String theory. String theory was first studied in the late 1960s[3] as a theory of the strong nuclear force before being abandoned in favor of the theory of quantum chromodynamics.

String theory

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. Five consistent versions of string theory were developed until it was realized in the mid-1990s that they were different limits of a conjectured single 11-dimensional theory now known as M-theory.[4] Many theoretical physicists, including Stephen Hawking, Edward Witten and Juan Maldacena, believe that string theory is a step towards the correct fundamental description of nature: it accommodates a consistent combination of quantum field theory and general relativity, agrees with insights in quantum gravity (such as the holographic principle and black hole thermodynamics) and has passed many non-trivial checks of its internal consistency.

Brane-world quantum gravity - Abstract - Journal of High Energy Physics. Quantum information. In physics and computer science, quantum information is information that is held in the state of a quantum system.

Quantum information

Quantum information is the basic entity that is studied in the growing field of quantum information theory, and manipulated using the engineering techniques of quantum information processing. Much like classical information can be processed with digital computers, transmitted from place to place, manipulated with algorithms, and analyzed with the mathematics of computer science, so also analogous concepts apply to quantum information. Quantum information[edit] Quantum information differs strongly from classical information, epitomized by the bit, in many striking and unfamiliar ways. Among these are the following: A unit of quantum information is the qubit. The study of all of the above topics and differences comprises quantum information theory. Quantum information theory[edit] How is information stored in a state of a quantum system?

Journals[edit] See also[edit] John C. Lilly. John Cunningham Lilly (January 6, 1915 – September 30, 2001) was a American physician, neuroscientist, psychoanalyst, psychonaut, philosopher, writer and inventor.

John C. Lilly

He was a researcher of the nature of consciousness using mainly isolation tanks,[1] dolphin communication, and psychedelic drugs, sometimes in combination. Early life and education[edit] John Lilly was born to a wealthy family on January 6, 1915, in Saint Paul, Minnesota. His father was Richard Coyle Lilly, president of the First National Bank of St.

Paul. Lilly showed an interest in science at an early age. While at St. Despite his father's wishes for him to go to an eastern Ivy-league college to become a banker, Lilly accepted a scholarship at the California Institute of Technology to study science. In 1934, Lilly read Aldous Huxley's Brave New World. Lilly became engaged to his first wife, Mary Crouch, at the beginning of his junior year at Caltech.