# What is the Bekenstein Hawking formula?

## What is the Bekenstein Hawking formula?

An important black hole observable is the Bekenstein-Hawking (BH) entropy, which is proportional to the area of the event horizon, SBH = Ah/(4G).

What is Hawking’s area theorem?

Hawking’s black-hole area theorem, also known as the second law of black hole mechanics, states that the total horizon area of a classical black hole cannot decrease over time. The theorem is named after physicist Stephen Hawking, who proposed it in 1971.

How do you calculate the area of a black hole?

The surface area, A g = 4 π R g 2 , of a Schwarzschild black hole determines its entropy, S = A g c 3 / 4 G ħ ≈ A g / A p l , where A p l is the Planck area: the entropy is the number of Planck areas in the horizon area.

### What is the black hole area theorem?

In 1971, Stephen Hawking proposed the area theorem, which set off a series of fundamental insights about black hole mechanics. The theorem predicts that the total area of a black hole’s event horizon — and all black holes in the universe, for that matter — should never decrease.

How do you calculate entropy of Von Neumann?

Entropy Associated with an n-Level System: Mixed States and, as the wavefunctions { | Ψ k 〉 } F are orthonormal, the von Neumann entropy (defined as S = − T r { ρ ^ ln ρ ^ } ) may be easily found: S M = − ∑ k = 1 n λ k ln λ k .

Do black holes have a surface area?

Instead of a singularity with no surface area, the black hole is a giant mass with a hard surface, and material being pulled closer — such as a star — would not actually fall into a black hole, but hit this hard surface and be destroyed. If that were the case, the collision should create a large burst of light.

#### What is the Schwarzschild radius for a black hole?

Black Hole Description One of the terms used with black holes is “photon sphere”, the radius of the orbit of light around the black hole. For 3 solar masses this radius is 13.5 km, 3/2 x the event horizon radius. The event horizon radius is also called the Schwarzschild radius.

What is Stephen Hawking’s theory of black hole formation?

That’s where Hawking came in. In 1971, he suggested that black holes formed in the chaotic environment of the earliest moments of the Big Bang. There, pockets of matter could spontaneously reach the densities needed to make black holes, flooding the cosmos with them well before the first stars twinkled.

What was Stephen Hawkings first theory?

Hawking was the first to set out a theory of cosmology explained by a union of the general theory of relativity and quantum mechanics.

## How do you do Schmidt decomposition?

1. For the Schmidt decomposition you first partition your space in two pieces, say A and B.
2. [continuing] |ψA,0⟩=1√2(|0⟩+|1⟩), |ψA,1⟩=1√2(|0⟩−|1⟩), and similarly for the second site (‘B’).