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  2. Vacuum energy - Wikipedia

    en.wikipedia.org/wiki/Vacuum_energy

    Using the upper limit of the cosmological constant, the vacuum energy of free space has been estimated to be 10 −9 joules (10 −2 ergs), or ~5 GeV per cubic meter. [3] However, in quantum electrodynamics , consistency with the principle of Lorentz covariance and with the magnitude of the Planck constant suggests a much larger value of 10 113 ...

  3. Quantum vacuum state - Wikipedia

    en.wikipedia.org/wiki/Quantum_vacuum_state

    The video of an experiment showing vacuum fluctuations (in the red ring) amplified by spontaneous parametric down-conversion.. If the quantum field theory can be accurately described through perturbation theory, then the properties of the vacuum are analogous to the properties of the ground state of a quantum mechanical harmonic oscillator, or more accurately, the ground state of a measurement ...

  4. Zero-point energy - Wikipedia

    en.wikipedia.org/wiki/Zero-point_energy

    The zero-point energy density of the vacuum, due to all quantum fields, is extremely large, even when we cut off the largest allowable frequencies based on plausible physical arguments. It implies a cosmological constant larger than the limits imposed by observation by about 120 orders of magnitude.

  5. QED vacuum - Wikipedia

    en.wikipedia.org/wiki/QED_vacuum

    The QED vacuum is subject to fluctuations about a dormant zero average-field condition; [4] Here is a description of the quantum vacuum: The quantum theory asserts that a vacuum, even the most perfect vacuum devoid of any matter, is not really empty. Rather the quantum vacuum can be depicted as a sea of continuously appearing and disappearing ...

  6. The Quantum Vacuum - Wikipedia

    en.wikipedia.org/wiki/The_Quantum_Vacuum:_An...

    The Quantum Vacuum: An Introduction to Quantum Electrodynamics is a physics textbook authored by Peter W. Milonni in 1993. The book provides a careful and thorough treatment of zero-point energy, spontaneous emission, the Casimir, van der Waals forces, Lamb shift and anomalous magnetic moment of the electron at a level of detail not found in other introductory texts to quantum electrodynamics ...

  7. Quantum fluctuation - Wikipedia

    en.wikipedia.org/wiki/Quantum_fluctuation

    3D visualization of quantum fluctuations of the quantum chromodynamics (QCD) vacuum [1]. In quantum physics, a quantum fluctuation (also known as a vacuum state fluctuation or vacuum fluctuation) is the temporary random change in the amount of energy in a point in space, [2] as prescribed by Werner Heisenberg's uncertainty principle.

  8. Casimir effect - Wikipedia

    en.wikipedia.org/wiki/Casimir_effect

    The vacuum has, implicitly, all of the properties that a particle may have: spin, [21] or polarization in the case of light, energy, and so on. On average, most of these properties cancel out: the vacuum is, after all, "empty" in this sense. One important exception is the vacuum energy or the vacuum expectation value of the energy. The ...

  9. Cosmological constant problem - Wikipedia

    en.wikipedia.org/wiki/Cosmological_constant_problem

    Depending on the Planck energy cutoff and other factors, the quantum vacuum energy contribution to the effective cosmological constant is calculated to be between 50 and as many as 120 orders of magnitude greater than has actually been observed, [1] [2] a state of affairs described by physicists as "the largest discrepancy between theory and ...