Birth of Particles in an Expanding Universe on a Quantum Computer express
The early universe resembled a rapidly inflating balloon: it expanded so fast that light couldn't keep up with its own edges. Then this frantic acceleration gave way to calm expansion. The balloon was no longer being blown up, and it began to slowly deflate. At the moment of the regime change, emptiness didn't stay empty: from it, as if from an overheated boiler, pairs of particles burst forth.
The authors of the new work reproduced this process on a quantum computer. They split the entire transition time into tiny steps — much like frame-by-frame filming of a bursting soap bubble. At each step, the computer calculated how many particle pairs had been born. This approach allowed them to see not only the final number of particles but also the process of their accumulation.
The experiment on a real IBM quantum processor showed that even the simplest version of the calculation suffers from errors on the order of one hundredth. It's like trying to hear a whisper in a noisy workshop — the signal is there, but it's hard to make out. Nevertheless, the very fact of a working prototype opens the way to more accurate simulations when quantum machines become cleaner.
The quantum simulator used only four qubits for a pair of particles with opposite momenta, as if two twins flew apart in different directions but remained connected by an invisible thread.
In Carl Sagan's novel "Contact," aliens use cosmological particle creation to transmit messages — here we see for the first time how this process can be recreated on an earthly device.