vendredi 7 décembre 2007
Einstein on Black Holes and White Holes
While Einstein and Planck had lunch today at a small restaurant near the
Black hole horizons can only absorb matter, while white hole horizons ostensibly recede from any incoming matter at the local speed of light, so that the infalling matter never crosses. The infalling matter is then scattered and reemitted at the death of the white hole, receding to infinity after having come very very close to the final singular point where the white hole is destroyed. The total proper time until an infalling object encounters the singular endpoint is the same as the proper time to be swallowed by a black hole, so the white hole picture does not say what happens to the infalling matter. Ignoring the classically unpredictable emissions of the white hole, the white hole and black hole are indistinguishable for external observers.
In quantum mechanics, the black hole emits Hawking radiation, and so can come to thermal equilibrium with a gas of radiation. Since a thermal equilbrium state is time reversal invariant, Hawking argued that the time reverse of a black hole in thermal equilibrium is again a black hole in thermal equilibrium.[1] This implies that black holes and white holes are the same object. The Hawking radiation from an ordinary black hole is then identified with the white hole emission. Hawking's semi-classical argument is reproduced in a quantum mechanical AdS/CFT treatment[2], where a black hole in Anti De Sitter space is described by a thermal gas in a gauge theory, whose time reversal is the same as itself.
White holes appear as part of the vacuum solution to the Einstein field equations describing a Schwarzschild wormhole. One end of this type of wormhole is a black hole, drawing in matter, and the other is a white hole, emitting matter. While this gives the impression that black holes in this universe may connect to white holes elsewhere, this turns out not to be the case for two reasons. First, Schwarzschild wormholes are unstable, disconnecting as soon as they form. Second, Schwarzschild wormholes are only a solution to the Einstein field equations in vacuum (when no matter interacts with the hole). Real black holes are formed by the collapse of stars. When the infalling stellar matter is added to a diagram of a black hole's history, it removes the part of the diagram corresponding to the white hole [1].
The existence of white holes that are not part of a wormhole is doubtful, as they appear to violate the second law of thermodynamics.
Quasars and active galactic nuclei are observed to spew out jets of matter. This is now believed to be the result of polar jets formed when matter falls into supermassive black holes at the centers of these objects. Prior to this model, white holes emitting matter were one possible explanation proposed.
A more recently proposed view of black holes might be interpreted as shedding some light on the nature of classical white holes. Some researchers proposed that when a black hole forms, a big bang occurs at the core which creates a new universe that expands into extra dimensions outside of the parent universe[3].
The initial feeding of matter from the parent universe's black hole and the expansion that follows in the new universe might be thought of as a cosmological type of white hole. Unlike traditional white holes, this type of white hole would not be localized in space in the new universe and its horizon would have to be identified with the cosmological horizon.
Einstein Hubble on White Holes
The Einstein-Hubble steering comittee worked very late last night on this center of the SUN White Hole investigations. After dinner at our favorite Provencal Decor style restaurant, the Olive Oil Cruet, in
For those not familiar with the topic, in astrophysics, a white hole is the time reversal of a black hole. While a black hole acts as an absorber for any matter that crosses the event horizon, a white hole acts as a source that ejects matter from its event horizon. The sign of the acceleration is invariant under time reversal, so both black and white holes attract matter. The potential difference between them is in the behavior at the horizon and the inversed polarization of the Higgs Field inside the White Hole.
Sometimes, it has been heard that Hawking argued that white holes are the same as black holes, once quantum mechanics is taken into account. We all three, Einstein, Hubble and Planck have emitted doubts that it could be not that simple.
However many scientists used to consider that Black hole horizons can only absorb matter, while white hole horizons ostensibly recede from any incoming matter at the local speed of light, so that the infalling matter never crosses. The infalling matter is then scattered and reemitted at the death of the white hole, receding to infinity after having come very very close to the final singular point where the white hole is destroyed. The total proper time until an infalling object encounters the singular endpoint is the same as the proper time to be swallowed by a black hole, so the white hole picture does not say what happens to the infalling matter. Ignoring the classically unpredictable emissions of the white hole, the white hole and black hole are indistinguishable for external observers.
In quantum mechanics, the black hole emits Hawking radiation, and so can come to thermal equilibrium with a gas of radiation. Since a thermal equilibrium state is time reversal invariant, Hawking argued that the time reverse of a black hole in thermal equilibrium is again a black hole in thermal equilibrium.[1] This implies that black holes and white holes are the same object. The Hawking radiation from an ordinary black hole is then identified with the white hole emission. Hawking's semi-classical argument is reproduced in a quantum mechanical AdS/CFT treatment[2], where a black hole in Anti De Sitter space is described by a thermal gas in a gauge theory, whose time reversal is the same as itself.
What we have experimented last night is that the White Hole, sitting at the center of the Sun, not only emit anti-matter, mainly anti-protons, as would be normally expected, but also rejects a form of, so far unknown, gravitational radiation which seem to be directly derived from quantic fluctuations in the inversed Higgs Field. Hubble is currently performing additional verifications on the results and will get back to us with more details soon.
Einstein for the Einstein-Hubble association.
mercredi 5 décembre 2007
Einstein Hubble on Vacuum Energy
Crisis meeting today, at lunch time, at the CERN cafeteria. The Einstein-Hubble scientific steering board, composed of Einstein, Hubble and Planck, was having lunch on a superb Tablecloth with assorted Provence Place Mats and Provence Napkins. Tastefull Provencal meals were being served in a bright Provencal Tableware when Planck raised the idea that Vacuum might not be as empty as one would thought but, instead, was filled with Vacuum Energy or 'Black Energy'.
As Planck explained, Vacuum energy is an underlying background energy that exists in space even when devoid of matter (known as free space). The vacuum energy results in the existence of most (if not all) of the fundamental forces - and thus in all effects involving these forces, too. It is observed in various experiments (like the spontaneous emission of light or gamma radiation, the Casimir effect, Van-Der Waals bonds, the Lamb shift, etc); and it is thought (but not yet demonstrated) to have consequences for the behavior of the Universe on cosmological scales.
Quantum field theory states that all of the various fundamental fields, such as the electromagnetic field, must be quantized at each and every point in space. In a naïve sense, a field in physics may be envisioned as if space were filled with interconnected vibrating balls and springs, and the strength of the field can be visualized as the displacement of a ball from its rest position. Vibrations in this field propagate and are governed by the appropriate wave equation for the particular field in question. The second quantization of quantum field theory requires that each such ball-spring combination be quantized, that is, that the strength of the field be quantized at each point in space. Canonically, the field at each point in space is a simple harmonic oscillator, and its quantization places a quantum harmonic oscillator at each point. Excitations of the field correspond to the elementary particles of particle physics. However, even the vacuum has a vastly complex structure. All calculations of quantum field theory must be made in relation to this model of the vacuum.
The vacuum has, implicitly, all of the properties that a particle may have: spin, or polarization in the case of light, energy, and so on. On average, all 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 quantization of a simple harmonic oscillator states that the lowest possible energy or zero-point energy that such an oscillator may have is
Summing over all possible oscillators at all points in space gives an infinite quantity. To remove this infinity, one may argue that only differences in energy are physically measurable, much as the concept of potential energy has been treated in classical mechanics for centuries. This argument is the underpinning of the theory of renormalization. In all practical calculations, this is how the infinity is always handled.
Vacuum energy can also be thought of in terms of virtual particles (also known as vacuum fluctuations) which are created and destroyed out of the vacuum. These particles are always created out of the vacuum in particle-antiparticle pairs, which shortly annihilate each-other and disappear. However, these particles and antiparticles may interact with others before disappearing, a process which can be mapped using Feynman diagrams. It is these fundamental interactions which give rise to all physical forces. Note that this method of computing vacuum energy is mathematically completely equivalent to having a quantum harmonic oscillator at each point, and therefore suffers the same renormalization problems.
Additional contributions to the vacuum energy come from spontaneous symmetry breaking in quantum field theory.
Needless to say that Einstein and Hubble were a bit excited by the fascinating implications of the Vacuum Energy. This, however, is left for the next issue of Extreme Science, the newsletter of the Einstein-Hubble scientific association. Coming soon!
As Planck explained, Vacuum energy is an underlying background energy that exists in space even when devoid of matter (known as free space). The vacuum energy results in the existence of most (if not all) of the fundamental forces - and thus in all effects involving these forces, too. It is observed in various experiments (like the spontaneous emission of light or gamma radiation, the Casimir effect, Van-Der Waals bonds, the Lamb shift, etc); and it is thought (but not yet demonstrated) to have consequences for the behavior of the Universe on cosmological scales.
Quantum field theory states that all of the various fundamental fields, such as the electromagnetic field, must be quantized at each and every point in space. In a naïve sense, a field in physics may be envisioned as if space were filled with interconnected vibrating balls and springs, and the strength of the field can be visualized as the displacement of a ball from its rest position. Vibrations in this field propagate and are governed by the appropriate wave equation for the particular field in question. The second quantization of quantum field theory requires that each such ball-spring combination be quantized, that is, that the strength of the field be quantized at each point in space. Canonically, the field at each point in space is a simple harmonic oscillator, and its quantization places a quantum harmonic oscillator at each point. Excitations of the field correspond to the elementary particles of particle physics. However, even the vacuum has a vastly complex structure. All calculations of quantum field theory must be made in relation to this model of the vacuum.
The vacuum has, implicitly, all of the properties that a particle may have: spin, or polarization in the case of light, energy, and so on. On average, all 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 quantization of a simple harmonic oscillator states that the lowest possible energy or zero-point energy that such an oscillator may have is
Summing over all possible oscillators at all points in space gives an infinite quantity. To remove this infinity, one may argue that only differences in energy are physically measurable, much as the concept of potential energy has been treated in classical mechanics for centuries. This argument is the underpinning of the theory of renormalization. In all practical calculations, this is how the infinity is always handled.
Vacuum energy can also be thought of in terms of virtual particles (also known as vacuum fluctuations) which are created and destroyed out of the vacuum. These particles are always created out of the vacuum in particle-antiparticle pairs, which shortly annihilate each-other and disappear. However, these particles and antiparticles may interact with others before disappearing, a process which can be mapped using Feynman diagrams. It is these fundamental interactions which give rise to all physical forces. Note that this method of computing vacuum energy is mathematically completely equivalent to having a quantum harmonic oscillator at each point, and therefore suffers the same renormalization problems.
Additional contributions to the vacuum energy come from spontaneous symmetry breaking in quantum field theory.
Needless to say that Einstein and Hubble were a bit excited by the fascinating implications of the Vacuum Energy. This, however, is left for the next issue of Extreme Science, the newsletter of the Einstein-Hubble scientific association. Coming soon!
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