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Inhomogeneous Quantum Quenches of Conformal Field Theory with Boundaries
Xinyu Liu1,2, Alexander McDonald1, Tokiro Numasawa3
1Princeton University, Department of Physics, Princeton, New Jersey 08544, USA.
Physical Review Letters
|June 23, 2025
Summary
We present a new method for calculating correlations in inhomogeneous quantum quenches within conformal field theory (CFT). This approach effectively handles spatial boundaries, revealing distinct behaviors in entanglement entropy evolution.
Area of Science:
- Quantum Field Theory
- Condensed Matter Physics
Background:
- Calculating time-dependent correlations in inhomogeneous quantum quenches is challenging.
- Previous analytical methods struggled to incorporate spatial boundary effects.
Purpose of the Study:
- Develop a generic method for calculating correlation functions in (1+1)-dimensional CFT after inhomogeneous quantum quenches.
- Investigate the impact of spatial boundaries on these dynamics.
- Analyze the time evolution of entanglement entropy.
Main Methods:
- A mirroring technique is employed to simplify calculations of Euclidean path integrals for generic postquench Hamiltonians.
- A specific class of Hamiltonians (Möbius, sine-square-deformation) allows for simpler calculations in a strip spacetime geometry.
- The method is applied to study the time evolution of entanglement entropy.
Main Results:
- The generic method successfully incorporates spatial boundary effects.
- For generic quenches, entanglement entropy exhibits discontinuities (shockwave fronts) from boundaries.
- Special quenches show simpler boundary effects without these discontinuities.
- The theoretical predictions align well with numerical results from free-fermion models.
Conclusions:
- The developed method provides a powerful tool for studying inhomogeneous quantum quenches with boundaries in CFT.
- Boundary effects significantly influence entanglement entropy evolution, leading to shockwave phenomena in generic cases.
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