A phase transition between different quantum phases (phases of matter at zero temperature). Contrary to classical phase transitions, quantum phase transitions can only be accessed by varying a physical parameter—such as magnetic field or pressure—at absolute zero temperature. The transition describes an abrupt change in the ground state of a many-body system due to its quantum fluctuations.
Questions tagged [quantum-phase-transition]
2 questions
4
votes
0 answers
How to calculate $\langle\sigma_i^z\rangle$ with the method of symmetry in Heisenberg XXZ model?
The Hamiltonian of Heisenberg's XXY model is given by:
$$
H=\sum_{j=1}^{N}\left[S_{j}^{x} S_{j+1}^{x}+S_{j}^{y} S_{j+1}^{y}+\Delta S_{j}^{z} S_{j+1}^{z}\right]
,$$
where $S_{j}^{u}=\sigma_{j}^{u} / 2(u=x, y, z), \sigma_{j}^{u}$ are the Pauli spin-…
narip
- 3,169
- 2
- 10
- 36
1
vote
1 answer
Find operation from GHZ state to one qubit state
Suppose I had some phase shifted GHZ state $\frac1{\sqrt2}(|00\cdots0\rangle+e^{i\phi}|11\cdots1\rangle)$, is there a way apply some operation such that I can get the same phase shift for some one qubit state ${\psi}$.
7337dtd
- 13
- 2