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Updated: Nov 2, 2025
07:56
A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
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Entanglement versus gap, quantum teleportation, and the AKLT model
1Laboratory for Physical Sciences, 8050 Greenmead Drive, College Park, MD 20740, United States of America.
Summary
Researchers created a spin-chain Hamiltonian with a stable Bell pair in its ground state. Increasing the energy gap of this Hamiltonian decreases the Bell pair
Area of Science:
- Quantum physics
- Condensed matter theory
- Quantum information science
Background:
- Quantum entanglement is fragile and easily disrupted by external factors.
- Entanglement can be stabilized in the ground state of gapped, time-independent Hamiltonians.
Purpose of the Study:
- To design a spin-chain Hamiltonian whose ground state encodes a Bell pair.
- To investigate the properties and stability of this entangled ground state.
Main Methods:
- Numerical study using full numerical diagonalization.
- Application of a tailored mean-field theory.
- Analysis of the Hamiltonian's gap and Bell pair fidelity.
Main Results:
- A spin-chain Hamiltonian was devised with a Bell pair in its ground state, located at opposite ends of the chain.
- The Hamiltonian was shown to be gapped through numerical simulations.
- A fundamental trade-off was observed: increasing the Hamiltonian's gap reduced the fidelity of the Bell pair.
Conclusions:
- The devised Hamiltonian provides a route to stabilizing entanglement in a specific spin-chain system.
- The study reveals an inherent tension between the gap size and entanglement fidelity in this model.
- Comparison with the Affleck, Kennedy, Lieb, and Tasaki (AKLT) model suggests it exhibits characteristics of 'failed quantum teleportation'.
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