A black hole is a place from which even light cannot escape. But quantum theory says it still glows faintly. This glow is called Hawking radiation. In space, it's impossible to spot: it's too faint. So physicists build models of black holes from ordinary materials. For example, from a chain of quantum spins — tiny magnetic arrows that obey the laws of the quantum world.
In the new work, they took such a chain and abruptly changed its properties, as if a star were instantly squeezed into a point. An analog of the event horizon emerged: a boundary beyond which information does not return. Then the scientists looked at what radiation the system emits. It turned out to be almost like that of a real black hole — thermal, with a characteristic temperature. But there are differences: the spectrum is slightly distorted, as if light passes through a translucent mirror.
To understand how accurately the model mimics a black hole, the scientists attached a sensor to the chain — a single qubit, the quantum analog of a bit. In the weak coupling regime, the sensor feels only the local temperature, like a thermometer at the surface. But if the coupling is too strong, the sensor 'drowns' in the overall noise and can no longer distinguish the signal from the horizon. This is an important practical takeaway: to see Hawking radiation, you need to tune the measuring device very carefully.
Such experiments are a bridge between the world of quantum mechanics and gravity. They allow us to test ideas that cannot be tested with real black holes. And perhaps, one day, they will help us understand how space and time work at the deepest level.
as written by the authors arXiv:2602.04593
We investigate the emergence and detection of Hawking radiation (HR) in a 1D chiral spin chain model, where the gravitational collapse is simulated by a sudden quantum quench that triggers a horizon-inducing phase transition. While our previous work Jaiswal [2025] established that this model mimics BH formation conditions even when the Hoop conjecture is seemingly violated, we here focus on the resulting stationary radiation spectrum and its detectability. By mapping the spin chain dynamics to a Dirac fermion in a curved (1 + 1)-dimensional spacetime, we analyze the radiation using two complementary approaches: field-theoretic modes and operational quantum sensors. First, using localized Gaussian wave packets to model realistic detectors, we find that the radiation spectrum exhibits deviations from the ideal Planckian form, analogous to frequency-dependent greybody factors, while retaining robust Poissonian statistics that signal the loss of formation-scale information. Second, we introduce a qubit coupled to the chain as a stationary Unruh-DeWitt detector. We demonstrate that the qubit functions as a faithful quantum sensor of the Hawking temperature only in the weak-coupling regime, where its population dynamics are governed solely by the bath spectral density. In the strong-coupling limit, the probe thermalizes with the global environment, obscuring the horizon-induced thermal signature. These results provide a clear operational protocol for distinguishing genuine analog HR from environmental noise in quantum simulation platforms.
The temperature of Hawking radiation for a black hole with the mass of the Sun is about one ten-millionth of a kelvin, which is much colder than the cosmic background.
In the movie 'Interstellar', the characters use a black hole for time travel, but with quantum simulators we can study its properties without leaving the lab.