Questions tagged [quantum-phase-transition]

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.

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Spin Hamiltonian to Quantum Circuits and are there any group theory associated with the quantum circuits?

Can we think of Quantum Circuits as another representation to describe the dynamics of a system other than its Hamiltonian? How can we go from the spin Hamiltonian version (for eg: SSH Model ...
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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 ...
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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(...