The delta function well (Equation 2.114) supports a single bound state (Equation 2.129). Calculate the geometric phase change whengradually increases fromα1toα2. If the increase occurs at a constant rate, (/dt=c)what is the dynamic phase change for this process?

Short Answer

Expert verified

The geometric phase is Yn(t)=0.The dynamic phase change for this process is

θ(t)=m6h2c(α23-α13).

Step by step solution

01

Define Dynamic phase.

Geometric phase is a phase difference gained during the course of a cycle when a system is subjected to cyclic adiabatic processes, which derives from the geometrical features of the Hamiltonian's parameter space in both classical and quantum mechanics.Dynamic phases take inspiration from dynamic timers and static phases to generate performance metrics for all functions performed in a single phase invocation.

02

Obtain the geometric phase.

Let the time independent wave function for the bound state be,ψ=he-αh.....

(1)

The equation 10.42 is given by,localid="1656050634693" role="math" Yn(t)=iRlRlψnl𝜕ψn𝜕RdR......(2)Inthiscase,R=α.So,𝜕ψ𝜕R=mh121αe-xh2+h-mxh2e-xh2

Thus,

ψ𝜕ψ𝜕R=mαh12hmα-mmαh3xe-2mαxh2=m2h2-m2αh4xe-2mαxh2ψ|𝜕ψ𝜕R=2m2h20e-2mαxh2dx-m2αh40xe-2mαxh2dx=mh2h22mα-2m2αh4h22mα2=12α-12α=0Substitutethevalueintheequation(2)toget:Yn(t)=0

03

Obtain the dynamic phase.

The dynamic phase change for this process is given by, θn(t)=1h0tEn(t')dt'.....(3)

But the energy in this case is E=-22h2.Thus,

θ(t)=-1h0T-mα22h2dt'=m2h3α1α2α2dt'dαdα=m2h3Cα1α2α2dα=m6h2c(α23-α13)θ(t)=m6h2c(α23-α13)

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