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Flat space vs curved space7/3/2023 ![]() ![]() ![]() Cosmological questions normally run on unimaginably large scales. With the quantum field simulator, cosmic phenomena, for example the production of particles due to the expansion of space, and spacetime curvature itself can be made measurable. He worked out the quantum field theoretical model with which the experimental results were quantitatively matched. This gives us the possibility to create conditions like in an expanding universe," explains Stefan Flörchinger, previously a scientist at the University of Heidelberg and since the beginning of this year at the University of Jena. The interaction between the atoms can be precisely adjusted by a magnetic field, which changes the speed of propagation of the wave-like excitations on the Bose-Einstein condensate.įor the waves on the condensate, the propagation speed depends on the density and the interaction of the atoms. At the same time, the atom cloud can be shaped almost arbitrarily in the remaining two dimensions, making it possible to realize curved spacetimes. Thus, excitations can only propagate in two spatial directions - space is two-dimensional. In the experiment conducted by the Heidelberg physicists, the atoms are trapped in a thin layer. In the universe there are three dimensions of the space and a fourth - that of the time. The shape of the atomic cloud determines the dimensionality and the properties of the space-time on which these excitations move like waves. changes in the energy state of the atoms, become visible. ![]() Oberthaler explains, the Bose-Einstein condensate acts as an ideal background on which the smallest excitations, i.e. This produces a Bose-Einstein condensate - a special quantum mechanical state of atomic gas that is reached at very cold temperatures. The quantum field simulator realized in the laboratory consists of a cloud of potassium atoms cooled to a few nanokelvin above absolute zero temperature. With his research group ,Synthetic Quantum Systems", he has developed a quantum field simulator for this purpose. Investigating the consequences of a curved spacetime is therefore a pressing research question," says Markus Oberthaler, a scientist at the Kirchhoff Institute for Physics at Heidelberg University. However, it is conceivable that our universe was curved in its initial phase. In a flat space like our present universe the shortest distance between two points is always a straight line. An essential part of cosmological models is the expansion and curvature of space. The origin of space and time on cosmic time scales from the Big Bang to the present is the subject of current research, which, however, can only refer to the observation of our one universe. The research results were published in ,Nature." In their research on ultracold quantum gases, they were thus able to simulate a whole family of curved universes in order to investigate different cosmological scenarios and compare them with the predictions of a quantum field theory model. Scientists at Heidelberg University have now succeeded in realizing an effective spacetime in a laboratory experiment that can be manipulated. In our universe - which is hardly measurably curved - the structure of this spacetime is predetermined. | © Celia Viermann Scientists simulate a whole family of universes with curvature in ultracold quantum gasesĪccording to Einstein’s general theory of relativity, space and time are inseparable. In addition, expansion was simulated by adjusting the interaction between the atoms. For the effective spacetime generated by a Bose-Einstein condensate, however, the research team manipulated only the density distribution of the condensate. ![]() To curve the spacetime of the universe, huge masses or energies are needed. Artistic representation of a curved space using the example of the Heidelberg experiment. ![]()
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