Sample interview questions: Describe the behavior of Hawking radiation and its relation to thermodynamics.
Sample answer:
- Hawking Radiation:
Hawking radiation is a theoretical phenomenon in which black holes are predicted to emit particles, leading to a gradual loss of mass and energy. This concept challenges the classical notion of black holes as perfect absorbers of everything that falls within their event horizon.
- Thermodynamic Aspects:
Black Hole Entropy:
According to thermodynamics, black holes have a finite entropy proportional to the area of their event horizon. This entropy is closely related to the number of possible microstates that the black hole can exist in, even though its macroscopic properties like mass and charge are fixed.
Bekenstein-Hawking Entropy:
Jacob Bekenstein proposed that black holes have an entropy proportional to their surface area. Stephen Hawking later provided a theoretical explanation for this entropy by showing that black holes emit thermal radiation. This radiation is known as Hawking radiation.
Hawking Radiation and Unitarity:
Hawking radiation introduces a paradox related to the unitarity of quantum mechanics. In quantum theory, information is not supposed to be lost. However, if black holes evaporate completely through Hawking radiation, information about the matter and energy that fell into the black hole may be irretrievably lost. Resolving this paradox remains a significant challenge in theoretical physics.
- Properties of Hawking Radiation:
Temperature and Spectrum:
Black holes are predicted to possess a temperature proportional to the square root of their gravitational constant and the event horizon’s surface gravity. This temperature determines the spectrum of Hawking radiation, which is a blackbody spectrum.
Thermal Evaporation:
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