Strongly Coupled ����-Symmetric Models in Holography

Area of Science:

• Quantum Field Theory
• Condensed Matter Physics
• High Energy Physics

Background:

• Non-Hermitian quantum field theories are crucial for modeling open quantum systems.
• Parity-time (PT) symmetry preservation ensures unitarity and allows for a Hermitian description via the Dyson map.
• PT symmetry breaking in non-Hermitian theories leads to loss of unitarity.

Purpose of the Study:

• To review holographic duals of strongly coupled PT-symmetric quantum field theories.
• To investigate the phase diagram of these theories.
• To explore spacetime-dependent non-Hermitian couplings, including quenches and lattices.

Main Methods:

• Construction of holographic duals for PT-symmetric quantum field theories.
• Analysis of phase diagrams.
• Study of non-Hermitian quenches and lattices with spacetime-dependent couplings.
• Investigation of gravity duals and their properties, such as the null energy condition.

Main Results:

• Holographic duals provide insights into the phase structure of PT-symmetric non-Hermitian theories.
• Spacetime-dependent non-Hermitian couplings, such as lattices, can violate the null energy condition in gravity duals.
• Non-Hermitian lattices exhibit phases with spontaneous PT symmetry breaking due to imaginary currents.
• These non-Hermitian lattices demonstrate a flow to a PT-symmetric fixed point in the infrared (IR) limit.

Conclusions:

• Non-Hermitian quantum field theories, particularly with spacetime-dependent couplings, offer a rich landscape of physical phenomena.
• Holographic methods are effective in studying these complex systems and their phase transitions.
• The observed spontaneous PT symmetry breaking and subsequent flow to a PT-symmetric fixed point highlight novel behaviors in non-Hermitian systems.