Thermal bath (thermodynamics)
Encyclopedia
In thermodynamics
and statistical mechanics
, a thermal bath is a reservoir of particles at finite temperature undergoing Brownian motion
, and that in thermal contact
with an object of interest. Because of its nonzero temperature, this system contains thermal energy
. This yields an environment where the fluctuations
due to thermal noise
are significant. This type of environment can have important effects at a molecular scale, such as for the operation of molecular motors
or stretching of DNA molecules.
Thermodynamics
Thermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation...
and statistical mechanics
Statistical mechanics
Statistical mechanics or statistical thermodynamicsThe terms statistical mechanics and statistical thermodynamics are used interchangeably...
, a thermal bath is a reservoir of particles at finite temperature undergoing Brownian motion
Brownian motion
Brownian motion or pedesis is the presumably random drifting of particles suspended in a fluid or the mathematical model used to describe such random movements, which is often called a particle theory.The mathematical model of Brownian motion has several real-world applications...
, and that in thermal contact
Thermal contact
In heat transfer and thermodynamics, a thermodynamic system is said to be in thermal contact with another system if it can exchange energy with it through the process of heat...
with an object of interest. Because of its nonzero temperature, this system contains thermal energy
Thermal energy
Thermal energy is the part of the total internal energy of a thermodynamic system or sample of matter that results in the system's temperature....
. This yields an environment where the fluctuations
Fluctuations
Fluctuations may refer to:* Quantum fluctuations arising from the uncertainty principle* Primordial fluctuations, density variations in the early universe* Statistical fluctuations, very important in statistics, statistical mechanics, and thermodynamics...
due to thermal noise
Fluctuation dissipation theorem
The fluctuation-dissipation theorem is a powerful tool in statistical physics for predicting the behavior of non-equilibrium thermodynamical systems. These systems involve the irreversible dissipation of energy into heat from their reversible thermal fluctuations at thermodynamic equilibrium...
are significant. This type of environment can have important effects at a molecular scale, such as for the operation of molecular motors
Molecular motors
Molecular motors are biological molecular machines that are the essential agents of movement in living organisms. Generally speaking, a motor may be defined as a device that consumes energy in one form and converts it into motion or mechanical work; for example, many protein-based molecular motors...
or stretching of DNA molecules.