Harmonic Oscillator
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An Harmonic Oscillator is a physical system whose equation of motion satisfies a second-order linear differential equation with constant coefficients.
- Context:
- It can be defined as the following
- [math]\displaystyle{ m\frac{d^2x}{dt}+c\frac{dx}{dt}+kx=F(t) }[/math]
- where [math]\displaystyle{ m,\;c }[/math] and [math]\displaystyle{ k }[/math] are constant coefficients, [math]\displaystyle{ x }[/math] is the displacement function and [math]\displaystyle{ F(t) }[/math] is an externally applied force. The solution of this second-order linear differential equation is usually a superposition of periodic functions and a time-dependent amplitude function
- It can range from being a Simple Harmonic Oscillator to being a Damped Harmonic Oscillator, Driven Harmonic Oscillator.
- Example(s):
- Counter-Example(s):
- See: Laplace's equation, Fourier series, Stability of Linear System, Second-Order Differential Equation, Helmholtz differential equation, Harmonic function.
References
2015
- (Wikipedia, 2015) ⇒ http://wikipedia.org/wiki/Harmonic_oscillator
- QUOTE: In classical mechanics, a harmonic oscillator is a system that, when displaced from its equilibrium position, experiences a restoring force, F, proportional to the displacement, x:
- [math]\displaystyle{ \vec F = -k \vec x \, }[/math]
- where k is a positive constant.
- If F is the only force acting on the system, the system is called a simple harmonic oscillator, and it undergoes simple harmonic motion: sinusoidal oscillations about the equilibrium point, with a constant amplitude and a constant frequency (which does not depend on the amplitude).
- If a frictional force (damping) proportional to the velocity is also present, the harmonic oscillator is described as a damped oscillator. Depending on the friction coefficient, the system can:
- Oscillate with a frequency lower than in the non-damped case, and an amplitude decreasing with time (underdamped oscillator).
- Decay to the equilibrium position, without oscillations (overdamped oscillator).
- The boundary solution between an underdamped oscillator and an overdamped oscillator occurs at a particular value of the friction coefficient and is called "critically damped."
- If an external time dependent force is present, the harmonic oscillator is described as a driven oscillator.
1992
- (Martin Braun, 1992)) ⇒ Martin Braun (1974, 1977 1982, 1992) "Differential Equations and their Applications", Spring-Verlag New York, Inc. ⇒ http://www.springer.com/us/book/9780387978949
- Section 2.6, Mechanical Vibrations, pages 165-171
1963
- (Feynman et al., 1963) ⇒ Richard P. Feynman, Robert B. Leighton and Matthew Sands (1963, 1977, 2006, 2010, 2013) "The Feynman Lectures on Physics": New Millennium Edition is now available online by the California Institute of Technology, Michael A. Gottlieb, and Rudolf Pfeiffer ⇒ http://www.feynmanlectures.caltech.edu/
- Chapter 21, Harmonic Oscillator ⇒http://www.feynmanlectures.caltech.edu/I_21.html