Long-range order

In physics, long-range order characterizes physical systems in which remote portions of the same sample exhibit correlated behavior.

Related Topics:
Physics - System - Correlated

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Let us discuss this by a correlation function, namely the spin-spin correlation function:

Related Topics:
Correlation function - Spin

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:G(x,x') = langle s(x)s(x') angle.

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This function is equal to unity when x=x' and decreases as the distance |x-x'| increases. Typically, it decays exponentially to zero at large distances, and the system is considered to be disordered. If, however, the correlation function decays to a constant value at large |x-x'| then the system is said to possess long-range order. If it decays to zero algebraically (i.e. as a polynomial) then we call it quasi-long-range order.

Related Topics:
Decays exponentially - Polynomial

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See also order-disorder

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