麻豆淫院

Quantum field theory (QFT) is a physics framework that describes how particles and forces behave based on principles rooted in quantum mechanics and Albert Einstein's special relativity theory. This framework predicts the emergence of various remarkable effects in curved spacetimes, including Hawking radiation.

Hawking radiation is the thermal radiation theorized to be emitted by black holes close to the event horizon (i.e., the boundary around a black hole after which gravity becomes too strong for anything to escape). As ascertaining the existence of Hawking radiation and testing other QFT predictions in space is currently impossible, physicists have been trying to identify physical systems that could mimic aspects of curved spacetimes in experimental settings.

Researchers at Sorbonne University recently identified a new promising experimental platform for simulating QFT and testing its predictions. Their proposed QFT simulator, outlined in a paper in 麻豆淫院ical Review Letters, consists of a one-dimensional quantum fluid made of polaritons, quasiparticles that emerge from strong interactions between photons (i.e., light particles) and excitons (i.e., bound pairs of electrons and holes in semiconductors).

"Our work is part of K茅vin Falque's Ph.D. thesis and ongoing efforts in our group to study predictions of QFT with laboratory experiments," Maxime J. Jacquet, co-senior author of the paper, told 麻豆淫院. "When we started the project, there existed only one proof of principle (by another group) that non-rotating black hole geometries could be created with polaritonic fluids of light, and numerical simulations showed that the Hawking effect in that experiment would be weak."

After running numerical simulations, Falque, Jacquet and their colleagues were able to identify conditions that could be better suited for the realization of the Hawking effect in experimental settings. As part of their recent study, Falque, who was a Ph.D. student at Sorbonne University at the time, implemented these conditions in the lab to ascertain their potential for simulating QFT.

"In the experiment, we not only showed that he could create a horizon with the polariton fluid, but also that we could measure the spectrum of the small amplitude excitation field (that actually simulates the quantum field) outside of and inside it," explained Falque, first author of the paper.

"Notably, we showed that dispersion (the fact that the oscillation frequency of waves depends on their wavelength nonlinearly) and the Doppler effect (the modification of the frequency by the flowing fluid) conspire together to create negative energy waves inside the horizon. Their existence is a key ingredient in the recipe for the Hawking effect."

The researchers found that they were able to precisely manipulate the polariton fluid they created to produce different horizon geometries. This is a remarkable and unprecedented achievement, which allows theoretical physicists to test QFT predictions with different horizon configurations.

"In the experiment, we generate, manipulate and measure photons: They pump the cavity to create the fluid, which eventually decays into photons that come out of the cavity that we can measure," said Alberto Bramati, head of the team at Sorbonne University. "This all-optical control is very flexible."

This recent study highlights the potential of polaritonic fluids of light for studying black holes and their underlying physics. In the future, the fluid and experimental set-up employed by Falque, Jacquet, Bramati and their colleagues could be used to re-create Hawking radiation in the lab and study the quantum mechanical effects associated with it.

"First, creating a horizon is no small feat, only a handful of other experimental systems have demonstrated their ability to date, with more to come hopefully," said Jacquet. "Second, the ability to fine tune the horizon geometry (how steep it is and also to deform the spacetime around it) is totally new and very interesting both for experimentalists (we can increase the strength of the Hawking effect) and theorists (who can test QFT in previously unavailable regimes).

"Third, the very high resolution that K茅vin obtained in his spectral measurements is very promising in terms of future experiments in which the variations of the Hawking effect as a function of frequency could be investigated."

This recent work could soon inspire other research groups to start using similar polariton fluids to simulate physical phenomena predicted by QFT. As part of their next studies, Falque, Jacquet, Bramati and their colleagues plan to use their newly proposed experimental platform to observe and study the Hawking effect, building on the promising preliminary data they collected.

"Measuring entanglement generation by the Hawking effect is a major goal for our future research," added Falque and Bramati. "In addition, we want to use the tunability of the platform to experimentally study how the Hawking effect reacts to various modifications we can make to the spacetime (steepness of the horizon, small modifications of the spacetime inside or outside the horizon).

"In the future, we would also like to create rotating black hole geometries to see how entanglement between the Hawking pairs behaves when other amplification phenomena (predicted with rotation) occur as well."

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