# What is Fermi golden rule formula?

## What is Fermi golden rule formula?

In quantum physics, Fermi’s golden rule is a formula that describes the transition rate (the probability of a transition per unit time) from one energy eigenstate of a quantum system to a group of energy eigenstates in a continuum, as a result of a weak perturbation.

**What is harmonic perturbation?**

Harmonic perturbation is a rare special case of time-dependent perturbations in which exact analysis exists. Based on harmonic perturbation, a quantum mechanical algorithm is devised to search the ground state of a given Hamiltonian.

### What is sudden approximation?

The sudden approximation can be used to calculate transition probabilities when the Hamiltonian changes rapidly. The reaction time is so short that the transition amplitude <β|U(t2,t1)|a> is simply given by the overlap <β|α>. The transition probability is |<β|α>|2.

**What do you mean by transition probabilities?**

the probability of moving from one state of a system into another state. If a Markov chain is in state i, the transition probability, pij, is the probability of going into state j at the next time step.

## What is classical turning point?

The classical turning point is defined as the point at which the potential energy U is approximately equal to total energy E (U≈E) and the kinetic energy equals zero. This occurs because the mass stops and reverses its velocity is zero.

**What is radiative transition in quantum mechanics?**

[′rād·ē‚ād·iv tran′zish·ən] (quantum mechanics) A change of a quantum-mechanical system from one energy state to another in which electromagnetic radiation is emitted.

### What is difference between time dependent and time independent perturbation theory?

In time-independent perturbation theory the perturbation Hamiltonian is static (i.e., possesses no time dependence). Time-dependent perturbation theory, developed by Paul Dirac, studies the effect of a time-dependent perturbation V(t) applied to a time-independent Hamiltonian H0.

**What is adiabatic and sudden approximation?**

This gradual change in the external conditions characterizes an adiabatic process. The quick movement which had a chaotic effect is often referred to as sudden. Note that the term ‘adiabatic’ does not imply anything with regard to the conservation of the energy of the system.

## What is adiabatic approximation?

In quantum mechanics, the adiabatic approximation refers to those solutions to the Schrödinger equation that make use of a time-scale separation between fast and slow degrees of freedom, and use this to find approximate solutions as product states in the fast and slow degrees of freedom.