Quantum Computer Played the Role of a Black Hole: What Physicists Saw ✛
A black hole is a place from which even light cannot escape. To study its behavior, scientists built a tiny replica on a quantum computer. They used a chain of 32 qubits, like a one-way street: the signal can only move forward, toward the center of the hole.
First, the physicists launched a single signal and observed how its energy depends on velocity. Outside, everything is normal: the signal can move in both directions. At the boundary, one of the energy branches became flat — meaning the signal gets stuck. Inside, new features appeared, and all paths lead only deeper. This is how they saw the light cone tilt: beyond the horizon, even light cannot turn around.
To measure the hole's temperature, they placed the signal just beyond the boundary and timed how long it took to reach the outer qubit. The hotter the hole, the faster the signal arrives. This is like judging the heat of an oven by how quickly bread toasts. When they turned on interactions between qubits, information scrambled very quickly, as if walls in a maze were being rearranged at every step. Previously, such phenomena were studied separately, but now they have been combined in a single experiment.
To extract the dispersion on 24 qubits, 4099 two-qubit CZ gates were needed after translation — a record depth for such simulations on superconducting hardware. In scrambling experiments, the number of CZ gates reached 5028 for intermediate values of φ.
The idea of simulating a black hole on a quantum computer echoes Greg Egan's novel 'Schild's Ladder', where physicists create artificial universes with tunable laws. Here, not the entire universe is tuned, but only a tiny part, the horizon and interior of a black hole.