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-------------------- 2567 - SPACETIME - creating new physics?
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- A mind once stretched never returns to its previous size. Space time is a stretch. Space is what keeps things from being on top of each other. Time is what keeps things from all happening at once.
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- Einstein invented spacetime to explain gravity. Gravity is bent spacetime. All objects, (ie:mass), move through gravity seeking the shortest distance and shortest time through the bent spacetime created by the mass. .
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- Ever since Einstein came up with this scientists have been scratching their heads about how to make sense of space and time. Before then, almost everybody thought Isaac Newton already had figured it all out.
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- Time flows equably without relation to anything external factors. Absolute space is also its own thing, always similar and immovable. Events are a physical reality performed independently on a neutral stage.
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- But Einstein’s theories turned Newton’s absolute space and time into a relativistic theory. His equations suggested a merged space-time, a new sort of arena in which the objects altered the space they moved in. No longer did space and time provide a featureless backdrop for matter and energy. Formerly independent and uniform, space and time became inseparable and variable.
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- As Einstein showed in his general theory of relativity, matter and energy warped the space-time surrounding them. That simple truth explained gravity. Newton’s apparent force of attraction became an illusion perpetrated by space-time geometry. It was the shape of space-time that dictated the motion of massive bodies, and at the same time massive bodies determined space-time’s shape.
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- Verification of Einstein’s space-time revolution came over 100 years ago, when an eclipse expedition confirmed his general theory’s fundamental prediction. The eclipse of the Sun provided a precise amount of bending of light passing near the edge of this massive body.
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- Now a new revolution is on the verge of answering that question again, based on insights from the other great physics surprise of the last century: quantum mechanics. Today’s revolution offers the potential for yet another rewrite of space-time’s theories. At the same time perhaps explaining why quantum mechanics gives us such weird theories.
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- Space-time and gravity must ultimately emerge from something else, Otherwise it’s hard to see how Einstein’s gravity and the math of quantum mechanics can reconcile their longstanding incompatibility. Einstein’s view of gravity as the manifestation of space-time geometry has been enormously successful but it doesn’t answer how the micro world works.
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- Quantum mechanics has perfectly described the machinations of matter and energy on the micro world atomic scale with unerring accuracy. Attempts to find coherent math that accommodates quantum weirdness with geometric gravity have met with difficult technical and conceptual roadblocks.
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- At least that has long been so for attempts to understand ordinary space-time. But clues to a possible path to progress around these roadblocks have emerged from the theoretical study of alternate space-time geometries.
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- One such geometry is known as “anti de Sitter space“. Space that is weirdly curved and tends to collapse on itself, rather than expanding as the universe we live in does. Quantum gravity is sufficiently rich and confusing that even mind created universes can shed enormous light on the physics.
Anti de Sitter Space is a strange type of space-time with unusual curvature that is nothing like the universe we live in, but could nevertheless provide clues to the quantum processes that may be responsible for producing ordinary space-time that we do live in.
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- Studies suggest that the math describing gravity, that is, space-time geometry, can be equivalent to the math of quantum physics in a “space of one less dimension“, two dimensions instead of three dimensions..
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- Think of a hologram, a flat, two-dimensional surface that incorporates a three-dimensional image. In a similar way, perhaps the four-dimensional geometry of space-time could be encoded in the math of quantum physics operating in three-dimensions.
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- Investigations using this geometry have revealed a surprising possibility: Space-time itself may be generated by quantum physics by the baffling phenomenon known as “quantum entanglement“.
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- As popularly explained, entanglement is a spooky connection linking particles separated even by great distances. If emitted from a common source, such particles remain entangled no matter how far they fly away from each other.
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- If you measure a property such as spin or polarization for one of particle, you then know what the result of the same measurement would be for the other particle. But before the measurement, those properties are not already determined, a counterintuitive fact verified by many experiments. It seems like the measurement at one place determines what the measurement will be at another distant location.
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- That sounds like entangled particles must be able to communicate faster than the speed of light. Otherwise it’s impossible to imagine how one of them could know what was happening to the other across a vast space-time expanse.
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- But as far as we know they actually don’t send any message at all. So how do entangled particles transcend the space-time gulf separating them? Perhaps the answer is they don’t have to because entanglement doesn’t “happen” in space-time. Entanglement “creates” space-time.
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- At least that’s the proposal that current research in theoretical universes has inspired. The emergence of space-time and gravity is a mysterious phenomenon of quantum many-body physics that we would like to understand.
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- Vigorous effort by several top-flight physicists has produced theoretical evidence that networks of entangled quantum states weave the space-time fabric. These quantum states are often described as “qubits”.
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- These are bits of quantum information, like ordinary computer bits, but existing in a mix of 1 and 0, not simply either 1 or 0. Entangled qubits create networks with geometry in space with an extra dimension beyond the number of dimensions that the qubits live in.
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- The quantum physics of qubits can then be equated to the geometry of a space with an extra dimension. Best of all, the geometry created by the entangled qubits may very well obey the equations from Einstein’s general relativity that describe motion due to gravity.
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- Apparently, a geometry with the right properties built from entanglement has to obey the gravitational equations of motion. This result further justifies the claim that space-time arises from entanglement.
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- Still, it remains to be shown that the clues found in these universes with extra dimensions will lead to the true story for the ordinary space-time in which real physics resides.
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- Nobody really knows exactly what quantum processes in the real world would be responsible for weaving space-time into such a fabric.
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- Our universe is extremely unnatural, a weird permutation among countless other possibilities, observed for no other reason than that its special conditions allowed life to arise. Or, are the properties of the universe to be inevitable, predictable, that is, ‘natural,’ locking together into a sensible pattern?
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- Are life and mind irrelevant to the structure of the universe, or are they central to it?
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- The nature of reality is revealed by the bizarre laws of quantum mechanics. According to the quantum theory, before the observation is made, a subatomic particle exists in several states, called a superposition. Once the particle is observed, it instantaneously collapses into a single position.
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- A natural universe is, in principle, a knowable universe. But if the universe is unnatural and fine-tuned for life, the lucky outcome of a cosmic roulette wheel, then it stands to reason that a vast and diverse “multiverse” of universes must exist beyond our reach. This multiverse renders our universe impossible to fully understand on its own terms.
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- A set of equations called the “Standard Model,” lack a sensible pattern and seem astonishingly fine-tuned for life
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- Einstein’s theory and the space-time concept break down inside black holes and at the moment of the big bang. Space-time, in other words, may be a translation of some other description of reality that, though more abstract or unfamiliar, can have greater explanatory power.”
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- These new discoveries have led us to explore new geometric formulations of particle-scattering amplitudes, hoping that it will lead away from our everyday, space-time-bound conception to some “grander” explanatory structure of reality.
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- Realty ain’t what it used to be. Say tuned, we till have more to learn.
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- December 27, 2019 2567
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--------------------- Saturday, December 28, 2019 --------------------
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