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Generalization of Wigner time delay to subunitary scattering systems
Lei Chen1,2, Steven M Anlage1,2, Yan V Fyodorov3,4
1Quantum Materials Center, Department of Physics, University of Maryland, College Park, Maryland 20742, USA.
Physical Review. E
|June 17, 2021
Summary
We present a generalized Wigner time delay for subunitary systems, linking resonant behavior to coherent perfect absorption (CPA). This method aids in identifying scattering matrix properties and achieving CPA at desired frequencies.
Area of Science:
- Quantum mechanics
- Wave scattering theory
- Condensed matter physics
Background:
- Wigner time delay is a key concept in quantum scattering.
- Understanding time delays in lossy systems is crucial for controlling wave dynamics.
- Coherent perfect absorption (CPA) offers possibilities for novel optical and electronic devices.
Purpose of the Study:
- To introduce a complex generalization of the Wigner time delay for subunitary scattering systems.
- To provide theoretical expressions for complex time delays.
- To establish a connection between time delays and coherent perfect absorption (CPA).
Main Methods:
- Developing theoretical expressions for complex time delays.
- Comparing theoretical predictions with experimental data from microwave graphs.
- Analyzing the resonant behavior of the real and imaginary parts of the complex time delay.
Main Results:
- Excellent agreement between theoretical complex time delays and experimental data.
- Demonstrated that resonant behavior in Re[τ] and Im[τ] indicates CPA conditions.
- Showcased the ability to identify scattering matrix poles and zeros from experimental data.
Conclusions:
- The complex Wigner time delay is a reliable indicator for CPA in subunitary systems.
- This work provides a method to experimentally determine scattering matrix properties.
- The findings enable achieving CPA at any desired frequency in complex scattering systems.
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