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In physics, the zero-point energy is the lowest possible energy that a quantum mechanical physical system may possess and is the energy of the ground state of the system. Physics (Greek Physis - φύσις in everyday terms is the Science of Matter and its motion. In Physics and other Sciences energy (from the Greek grc ἐνέργεια - Energeia, "activity operation" from grc ἐνεργός Quantum mechanics is the study of mechanical systems whose dimensions are close to the Atomic scale such as Molecules Atoms Electrons In Physics the word system has a technical meaning namely it is the portion of the physical Universe chosen for analysis In Quantum mechanics, a stationary state is an Eigenstate of a Hamiltonian, or in other words a state of definite energy The concept was first proposed by Albert Einstein and Otto Stern in 1913. Albert Einstein ( German: ˈalbɐt ˈaɪ̯nʃtaɪ̯n; English: ˈælbɝt ˈaɪnstaɪn (14 March 1879 – 18 April 1955 was a German -born theoretical Otto Stern was also the penname of German women's rights activist Louise Otto-Peters (1819-1895 TEB728: after a long discussion on the The term "zero-point energy" is a translation of the German Nullpunktenergie. All quantum mechanical systems have a zero point energy. The term arises commonly in reference to the ground state of the quantum harmonic oscillator and its null oscillations. The quantum harmonic oscillator is the quantum mechanical analogue of the classical harmonic oscillator.

In quantum field theory, it is a synonym for the vacuum energy, an amount of energy associated with the vacuum of empty space. In quantum field theory (QFT the forces between particles are mediated by other particles Vacuum energy is an underlying background Energy that exists in Space even when devoid of Matter (known as Free space) This vacuum means "absence of matter" or "an empty area or space" for the cleaning appliance see Vacuum cleaner. Space is the extent within which Matter is physically extended and objects and Events have positions relative to one another In cosmology, the vacuum energy is taken to be the origin of the cosmological constant which is thought by many to produce dark energy. Physical cosmology, as a branch of Astronomy, is the study of the large-scale structure of the Universe and is concerned with fundamental questions about its In Physical cosmology, the cosmological constant (usually denoted by the Greek capital letter Lambda: Λ was proposed by Albert Einstein as a modification In Physical cosmology, dark energy is a hypothetical exotic form of Energy that permeates all of space and tends to increase the rate of expansion of the universe Experimentally, the zero-point energy of the vacuum leads directly to the Casimir effect, and is directly observable in nanoscale devices. In Physics, the Casimir effect and the Casimir-Polder force are physical forces arising from a quantized field. Nanotechnology, sometimes shortened to nanotech, refers to a field of Applied science whose theme is the control of matter on an Atomic and Molecular

Because zero point energy is the lowest possible energy a system can have, this energy cannot be removed from the system. A related term is zero-point field, which is the lowest energy state of a field, i. In Quantum field theory, the zero-point field is the lowest energy state of a field, i In Physics, a field is a Physical quantity associated to each point of Spacetime. e. its ground state, which is non-zero. In Quantum mechanics, a stationary state is an Eigenstate of a Hamiltonian, or in other words a state of definite energy [1]

Despite the definition, the concept of zero-point energy, and the hint of a possibility of extracting "free energy" from the vacuum, has attracted the attention of amateur inventors. Numerous so-called free energy devices, exploiting the idea, have been proposed. The term perpetual motion, taken literally refers to movement that goes on forever As a result of this activity, and its intriguing theoretical explanation, it has taken on a life of its own in popular culture, appearing in science fiction books, games, movies and TV series (such as Stargate SG-1 and Stargate Atlantis). [2][3]

Contents

History

In 1900, Max Planck derived the formula for the energy of a single "energy radiator", i. e. a vibrating atomic unit, as:

\epsilon = \frac{h\nu}{ e^{\frac{h\nu}{kT}}-1}
Here, h is Planck's constant, ν is the frequency, k is Boltzmann's constant, and T is the absolute temperature. The Planck constant (denoted h\ is a Physical constant used to describe the sizes of quanta. Frequency is a measure of the number of occurrences of a repeating event per unit Time. Bridge from macroscopic to microscopic physics Boltzmann's constant k is a bridge between Macroscopic and microscopic physics Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature

In 1913, using this formula as a basis, Albert Einstein and Otto Stern published a paper of great significance in which they suggested for the first time the existence of a residual energy that all oscillators have at absolute zero. Albert Einstein ( German: ˈalbɐt ˈaɪ̯nʃtaɪ̯n; English: ˈælbɝt ˈaɪnstaɪn (14 March 1879 – 18 April 1955 was a German -born theoretical Otto Stern was also the penname of German women's rights activist Louise Otto-Peters (1819-1895 TEB728: after a long discussion on the They called this "residual energy" and then Nullpunktsenergie (in German), which later became translated as zero-point energy. They carried out an analysis of the specific heat of hydrogen gas at low temperature, and concluded that the data are best represented if the vibrational energy is taken to have the form:[4]

\epsilon = \frac{h\nu}{ e^{\frac{h\nu}{kT}}-1} + \frac{h\nu}{2}

Thus, according to this expression, even at absolute zero the energy of an atomic system has the value ½hν. Absolute zero is the point at which molecules do not move (relative to the rest of the body more than they are required to by a quantum mechanical effect called Zero-point [5]

Foundational physics

In classical physics, the energy of a system is relative, and is defined only in relation to some given state (often called reference state). Typically, one might associate a motionless system with zero energy, although doing so is purely arbitrary.

In quantum physics, it is natural to associate the energy with the expectation value of a certain operator, the Hamiltonian of the system. Quantum mechanics is the study of mechanical systems whose dimensions are close to the Atomic scale such as Molecules Atoms Electrons In physics an operator is a function acting on the space of Physical states As a resultof its application on a physical state another physical state is obtained In Quantum mechanics, the Hamiltonian H is the Observable corresponding to the Total energy of the system For almost all quantum-mechanical systems, the lowest possible expectation value that this operator can obtain is not zero; this lowest possible value is called the zero-point energy. (Caveat: If we add an arbitrary constant to the Hamiltonian, we get another theory which is physically equivalent to the previous Hamiltonian. Because of this, only relative energy is observable, not the absolute energy. This does not change the fact that the minimum momentum is non-zero, however. )

The origin of a minimal energy that isn't zero can be intuitively understood in terms of the Heisenberg uncertainty principle. In Quantum physics, the Heisenberg uncertainty principle states that locating a particle in a small region of space makes the Momentum of the particle uncertain This principle states that the position and the momentum of a quantum mechanical particle cannot both be known simultaneously, with arbitrary accuracy. In Classical mechanics, momentum ( pl momenta SI unit kg · m/s, or equivalently N · s) is the product If the particle is confined to a potential well, then its position is at least partly known: it must be within the well. A potential well is the region surrounding a Local minimum of Potential energy. Thus, one may deduce that within the well, the particle cannot have zero momentum, as otherwise the uncertainty principle would be violated. Because the kinetic energy of a moving particle is proportional to the square of its velocity, it cannot be zero either. The kinetic energy of an object is the extra Energy which it possesses due to its motion This example, however, is not applicable to a free particle - the kinetic energy of which can be zero.

In thermodynamics, since temperature is defined as the average translational kinetic energy of a moving particle, the existence of non-zero minimal energy of the particle implies that it is impossible to achieve the temperature of absolute zero. In Physics, thermodynamics (from the Greek θερμη therme meaning " Heat " and δυναμις dynamis meaning " Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature Absolute zero is the point at which molecules do not move (relative to the rest of the body more than they are required to by a quantum mechanical effect called Zero-point

Varieties of zero-point energy

The idea of zero-point energy occurs in a number of situations, and it is important to distinguish these, and note that there are many closely related concepts.

In ordinary quantum mechanics, the zero-point energy is the energy associated with the ground state of the system. In Quantum mechanics, a stationary state is an Eigenstate of a Hamiltonian, or in other words a state of definite energy The most famous such example is the energy E={\hbar\omega\over 2} associated with the ground state of the quantum harmonic oscillator. The quantum harmonic oscillator is the quantum mechanical analogue of the classical harmonic oscillator. More precisely, the zero-point energy is the expectation value of the Hamiltonian of the system. In Quantum mechanics, the Hamiltonian H is the Observable corresponding to the Total energy of the system

In quantum field theory, the fabric of space is visualized as consisting of fields, with the field at every point in space and time being a quantized simple harmonic oscillator, with neighboring oscillators interacting. In Physics, a field is a Physical quantity associated to each point of Spacetime. This article is about the harmonic oscillator in classical mechanics In this case, one has a contribution of E={\hbar\omega\over 2} from every point in space, resulting in a technically infinite zero-point energy. The zero-point energy is again the expectation value of the Hamiltonian; here, however, the phrase vacuum expectation value is more commonly used, and the energy is called the vacuum energy. In Quantum field theory the vacuum expectation value (also called condensate) of an operator is its average Expected value in the vacuum Vacuum energy is an underlying background Energy that exists in Space even when devoid of Matter (known as Free space)

In quantum perturbation theory, it is sometimes said that the contribution of one-loop and multi-loop Feynman diagrams to elementary particle propagators are the contribution of vacuum fluctuations or the zero-point energy to the particle masses. This article describes perturbation theory as a general mathematical method In Physics, a one-loop Sander-Feynman diagram is a connected Feynman diagram with only one cycle ( Unicyclic) Motivation and history When calculating Scattering cross sections in Particle physics, the interaction between particles can be described In Particle physics, an elementary particle or fundamental particle is a particle not known to have substructure that is it is not known to be made In Quantum mechanics and Quantum field theory, the propagator gives the Probability amplitude for a particle to travel from one place to another in a given In Physics, a virtual particle is a particle that exists for a limited time and space introducing uncertainty in their energy and momentum due to the Heisenberg Uncertainty Mass is a fundamental concept in Physics, roughly corresponding to the Intuitive idea of how much Matter there is in an object

Experimental evidence

The simplest experimental evidence for the existence of zero-point energy in quantum field theory is the Casimir effect. In Physics, the Casimir effect and the Casimir-Polder force are physical forces arising from a quantized field. This effect was proposed in 1948 by Dutch physicist Hendrik B. G. Casimir, who considered the quantized electromagnetic field between a pair of grounded, neutral metal plates. Year 1948 ( MCMXLVIII) was a Leap year starting on Thursday (link will display the 1948 calendar of the Gregorian calendar. The Netherlands ( Dutch:, ˈnedərlɑnt is the European part of the Kingdom of the Netherlands, which consists of the Netherlands the Netherlands A physicist is a Scientist who studies or practices Physics. Physicists study a wide range of physical phenomena in many branches of physics spanning Hendrik Brugt Gerhard Casimir ( July 15, 1909 in 's-Gravenhage, Netherlands &ndash May 4, 2000 in Heeze The electromagnetic field is a physical field produced by electrically charged objects. A small force can be measured between the plates, which is directly ascribable to a change of the zero-point energy of the electromagnetic field between the plates.

Although the Casimir effect at first proved hard to measure, because its effects can be seen only at very small distances, the effect is taking on increasing importance in nanotechnology. Nanotechnology, sometimes shortened to nanotech, refers to a field of Applied science whose theme is the control of matter on an Atomic and Molecular Not only is the Casimir effect easily and accurately measured in specially designed nanoscale devices, but it increasingly needs to be taken into account in the design and manufacturing processes of small devices. It can exert significant forces and stress on nanoscale devices, causing them to bend, twist, stick and break.

Other experimental evidence includes spontaneous emissions of light (photons) by atoms and nuclei, observed Lamb shift of positions of energy levels of atoms, anomalous value of electron's gyromagnetic ratio, etc. Spontaneous emission is the process by which a light source such as an Atom, Molecule, Nanocrystal or nucleus in an Excited state In Physics, the photon is the Elementary particle responsible for electromagnetic phenomena History See also Atomic theory, Atomism The concept that matter is composed of discrete units and cannot be divided into arbitrarily tiny In Physics, the Lamb shift, named after Willis Lamb (1913-2008 is a small difference in Energy between two Energy levels ^2S_{1/2} A quantum mechanical system or particle that is bound, confined spacially can only take on certain discrete values of energy as opposed to classical particles which In Physics, the gyromagnetic ratio (also sometimes known as the magnetogyric ratio in other disciplines of a particle or system is the Ratio of its

Gravitation and cosmology

Unsolved problems in physics: Why doesn't the zero-point energy of vacuum cause a large cosmological constant? What cancels it out?

In cosmology, the zero-point energy offers an intriguing possibility for explaining the speculative positive values of the proposed cosmological constant. This is a list of some of the major unsolved problems in Physics. This vacuum means "absence of matter" or "an empty area or space" for the cleaning appliance see Vacuum cleaner. In Physical cosmology, the cosmological constant (usually denoted by the Greek capital letter Lambda: Λ was proposed by Albert Einstein as a modification Physical cosmology, as a branch of Astronomy, is the study of the large-scale structure of the Universe and is concerned with fundamental questions about its In Physical cosmology, the cosmological constant (usually denoted by the Greek capital letter Lambda: Λ was proposed by Albert Einstein as a modification In brief, if the energy is "really there", then it should exert a gravitational force. Newton 's law of universal Gravitation is a physical law describing the gravitational attraction between bodies with mass In general relativity, mass and energy are equivalent; both produce a gravitational field. General relativity or the general theory of relativity is the geometric theory of Gravitation published by Albert Einstein in 1916 Mass is a fundamental concept in Physics, roughly corresponding to the Intuitive idea of how much Matter there is in an object

One obvious difficulty with this association is that the zero-point energy of the vacuum is absurdly large. Naively, it is infinite, but one must argue that new physics takes over at the Planck scale, and so its growth is cut off at that point. In Particle physics and Physical cosmology, the Planck scale is an Energy scale around 1 Even so, what remains is so large that it would visibly bend space, and thus, there seems to be a contradiction. There is no easy way out, and reconciling the seemingly huge zero-point energy of space with the observed zero or small cosmological constant has become one of the important problems in theoretical physics, and has become a criterion by which to judge a candidate Theory of Everything. A theory of everything ( TOE) is a putative Theory of Theoretical physics that fully explains and links together all known physical phenomena

Levitation and inertia

Professor Ulf Leonhardt and Dr Thomas Philbin, from the University of St Andrews in Scotland, have worked out a way of reversing the zero-point energy phenomenon known as the Casimir force, so that it repels instead of attracting. The University of St Andrews is the oldest University in Scotland and third oldest in the English-speaking world, having been founded between Scotland ( Gaelic: Alba) is a Country in northwest Europethat occupies the northern third of the island of Great Britain. In Physics, the Casimir effect and the Casimir-Polder force are physical forces arising from a quantized field. Their discovery could ultimately lead to frictionless micro-machines with moving parts that levitate. Levitation (from Latin levitas "lightness" is the process by which an object is suspended against Gravity, in a stable position [6]

Rueda, Haisch and Puthoff[7][8][9] have proposed that an accelerated massive object interacts with the zero point field to produce an electromagnetic drag force which gives rise to the phenomenon of inertia; see stochastic electrodynamics. The vis insita or innate force of matter is a power of resisting by which every body as much as in it lies endeavors to preserve in its present state whether it be of rest or of moving In theoretical physics Stochastic electrodynamics (SED refers to a theory which posits that the interaction of Elementary particles with the vacuum radiation field or

"Free energy" devices

The Casimir effect has established zero point energy as an uncontroversial and scientifically accepted phenomenon. In Physics, the Casimir effect and the Casimir-Polder force are physical forces arising from a quantized field. Science (from the Latin scientia, meaning " Knowledge " or "knowing" is the effort to discover, and increase human understanding The concept of zero point energy has also become associated with pseudoscience, particularly the design and invention of "free energy" devices, which are essentially perpetual motion machines. Pseudoscience is defined as a body of knowledge methodology belief or practice that is claimed to be Scientific or made to appear scientific but does not adhere to the Free energy suppression is a Conspiracy theory that claims that advanced Technology that would reshape current electrical generation methods is being suppressed The term perpetual motion, taken literally refers to movement that goes on forever

References

  1. ^ Gribbin, John (1998). Q is for Quantum - An Encyclopedia of Particle Physics. Touchstone Books. ISBN 0-684-86315-4.  
  2. ^ Zero Point Energy goes Hollywood!. Retrieved on 2008-04-18. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1025 - Bolesław Chrobry is crowned in Gniezno, becoming the first King of Poland.
  3. ^ Zero Point Module - Wikipedia. Retrieved on 2008-04-18. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1025 - Bolesław Chrobry is crowned in Gniezno, becoming the first King of Poland.
  4. ^ Laidler, Keith, J. (2001). The World of Physical Chemistry. Oxford University Press. ISBN 0198559194.  
  5. ^ Introduction to Zero-Point Energy - Calphysics Institute
  6. ^ Telegraph article Physicists have 'solved' mystery of levitation published July 8, 2007 See also physicsworld and st-andrews.ac.uk.
  7. ^ Haisch, Bernard; Alphonso Rueda, H. E. Puthoff (February 1994). "Inertia as a zero-point-field Lorentz force". Physical Review A 49 (2): 678-694.  
  8. ^ Rueda, Alfonso; Bernhard Haisch (1998). "Contribution to inertial mass by reaction of the vacuum to accelerated motion". Found. Phys. 28: 1057-1108.  
  9. ^ Rueda, Alfonso; Bernhard Haisch (1998). "Inertia as reaction of the vacuum to accelerated motion". Phys. Lett. A240: 115-126.  

Further reading

External links

Dictionary

zero-point energy

-noun

  1. The energy possessed by something at a temperature of absolute zero
  2. (physics) The lowest possible energy of any quantum mechanical system; a consequence of the uncertainty principle
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