Macroscopic quantum self-trapping
Encyclopedia
In quantum mechanics
, macroscopic quantum self-trapping is a phenomenon occurring in the state of matter
called the Bose-Einstein condensate between two superconductors linked by a non-conducting barrier known as a Josephson junction
.
While the tunneling of a particle through classically forbidden barriers can be described by the particle's wave function, the wave function is merely a probability of tunneling. Although various factors can increase or decrease the probability of tunneling, one can not be certain that tunneling will never occur.
When two condensates are placed in a double potential well
and the phase and population differences are such that the system is in equilibrium
, the population difference will remain fixed. This is not to say that tunneling does not occur — rather, in the event that a particle tunnels through the barrier, another particle tunnels in the opposite direction. Because the identity of individual particles is lost in that case, no tunneling can be observed, and the system is considered to remain at rest
.
Introduction to quantum mechanics
Quantum mechanics is the body of scientific principles that explains the behavior of matter and its interactions with energy on the scale of atoms and atomic particles....
, macroscopic quantum self-trapping is a phenomenon occurring in the state of matter
Phase (matter)
In the physical sciences, a phase is a region of space , throughout which all physical properties of a material are essentially uniform. Examples of physical properties include density, index of refraction, and chemical composition...
called the Bose-Einstein condensate between two superconductors linked by a non-conducting barrier known as a Josephson junction
Josephson effect
The Josephson effect is the phenomenon of supercurrent across two superconductors coupled by a weak link...
.
While the tunneling of a particle through classically forbidden barriers can be described by the particle's wave function, the wave function is merely a probability of tunneling. Although various factors can increase or decrease the probability of tunneling, one can not be certain that tunneling will never occur.
When two condensates are placed in a double potential well
Potential well
A potential well is the region surrounding a local minimum of potential energy. Energy captured in a potential well is unable to convert to another type of energy because it is captured in the local minimum of a potential well...
and the phase and population differences are such that the system is in equilibrium
Mechanical equilibrium
A standard definition of static equilibrium is:This is a strict definition, and often the term "static equilibrium" is used in a more relaxed manner interchangeably with "mechanical equilibrium", as defined next....
, the population difference will remain fixed. This is not to say that tunneling does not occur — rather, in the event that a particle tunnels through the barrier, another particle tunnels in the opposite direction. Because the identity of individual particles is lost in that case, no tunneling can be observed, and the system is considered to remain at rest
Rest (physics)
Rest in physics refers to an object being stationary relative to a particular frame of reference or another object. According to the theory of relativity it is said that an object is: at rest relative to another. For example, a train decelerates on approach to a station and eventually stops...
.