In physics, a physical system is a portion of the physical universe chosen for analysis. Everything outside the system is known as the environment. The environment is ignored except for its effects on the system.
The split between system and environment is the analyst's choice, generally made to simplify the analysis. For example, the water in a lake, the water in half of a lake, or an individual molecule of water in the lake can each be considered a physical system. An isolated system is one that has negligible interaction with its environment. Often a system in this sense is chosen to correspond to the more usual meaning of system, such as a particular machine.
In the study of quantum coherence, the "system" may refer to the microscopic properties of an object (e.g. the mean of a pendulum bob), while the relevant "environment" may be the internal degrees of freedom, described classically by the pendulum's thermal vibrations.
See also
Conceptual systems
Phase space
Physical phenomenon
Physical ontology
Signal-flow graph
Systems Engineering
Systems Science
Thermodynamic system
External links
Conceptual vs Physical Systems
Research in simulation and modeling of various physical systems
vte
Systems science
System
types
Anatomical Art Biological Complex Complex adaptive Conceptual Coupled human–environment Database Dynamical Ecological Economic Energy Formal Holarchic Information Legal Measurement Metric Multi-agent Nervous Nonlinear Operating Physical Planetary Political Sensory Social Star Writing
Concepts
Doubling time Leverage points Limiting factor Negative feedback Positive feedback
Theoretical
fields
Chaos theory Complex systems Control theory Cybernetics Earth system science Living systems Sociotechnical system Systemics Urban metabolism World-systems theory
Analysis Biology Dynamics Ecology Engineering Neuroscience Pharmacology Psychology Theory Thinking
Scientists
Alexander Bogdanov Russell L. Ackoff William Ross Ashby Ruzena Bajcsy Béla H. Bánáthy Gregory Bateson Anthony Stafford Beer Richard E. Bellman Ludwig von Bertalanffy Margaret Boden Kenneth E. Boulding Murray Bowen Kathleen Carley Mary Cartwright C. West Churchman Manfred Clynes George Dantzig Edsger W. Dijkstra Fred Emery Heinz von Foerster Stephanie Forrest Jay Wright Forrester Barbara Grosz Charles A. S. Hall Mike Jackson Lydia Kavraki James J. Kay Faina M. Kirillova George Klir Allenna Leonard Edward Norton Lorenz Niklas Luhmann Humberto Maturana Margaret Mead Donella Meadows Mihajlo D. Mesarovic James Grier Miller Radhika Nagpal Howard T. Odum Talcott Parsons Ilya Prigogine Qian Xuesen Anatol Rapoport John Seddon Peter Senge Claude Shannon Katia Sycara Eric Trist Francisco Varela Manuela M. Veloso Kevin Warwick Norbert Wiener Jennifer Wilby Anthony Wilden
Applications
Systems theory in anthropology Systems theory in archaeology Systems theory in political science
Organizations
List Principia Cybernetica
Hellenica World - Scientific Library
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