Quantum Photonics Lecture by Professor Christine Silberhorn

Jul 12, 2024

Quantum Photonics Lecture by Professor Christine Silberhorn

Introduction

  • Deep Thurshree: Coordinator of Pix2Day webinar series, IIT Madras.
  • Professor Christine Silberhorn: Chair of the Integrated Quantum Optics Group, Paderborn University.
  • Topic: Quantum Photonics.
  • Moderator: Professor Deepa Venkatesh and Professor Vijay Krishnadas.
  • Participants & Panel: Professor Tagarajan and CTO Arnab Ghoshami.

Professional Background of Professor Christine Silberhorn

  • 2005: Joined Max Planck Institute for Quantum Optics, heading the Junior Research Group in Integrated Quantum Optics.
  • 2008-2010: Max Planck Institute for the Science of Light in Erlangen.
  • 2011: Awarded Got Fried Wilhelm Leibniz Prize.
  • 2017: European Research Council Award.
  • 2019: Fellow of Max Planck School of Photonics and the Optical Society of America.
  • Renowned for contributions to quantum optics, quantum computation, and quantum communication.

Presentation: Quantum Photonics using Nonlinear Integrated Optics and Pulsed Light

Motivation & Goals

  • Objective: Building quantum networks and multi-dimensional photonic quantum systems.
  • Applications: Quantum Internet, Neural Networks, Photonic Computation, Metrology, and Quantum Communication.

Photonic Quantum Computation & Simulation

  • Key Milestones: LOQC (2001) by Nilsson.
  • Challenges: High resource requirements.
  • Alternatives: Measurement-based quantum photonics, easier to implement systems targeting quantum simulations.

Boson Sampling

  • Importance: Demonstrates quantum computational advantage.
  • Breakthrough Experiment: China’s Gaussian boson sampling (2020) using input squeezed states for scalability.
  • Contributions: Developed theories for Gaussian boson sampling as a scalable method.

Research Focus Areas

Integrated Quantum Optics

  • Platforms: Lithium niobate, known for stable, scalable, and low-loss properties.
  • Applications: Photon pair generation, up/down conversion, quantum memories, and electro-optic switches.
  • Key Projects: High-quality photonic circuits and modules, non-linear integrated optics.

Photonic Devices Developed

  • Notable Devices: Noon state generators, polarization-entangled photon sources, squeezers, and resonators.
  • Advanced Projects: Monolithic integration of PDC sources, on-chip delay lines, and interferometers.
  • HOM (Hong-Ou-Mandel) Interference: Demonstrated with high visibility and precision delay lines.

Time-Multiplexed Quantum Systems

Quantum Walks

  • Classical vs Quantum Walks: Simulations of propagation phenomena using random walks vs quantum interference in quantum walks.
  • Experimental Setup: Coin encoding using polarization; step encoding using time bins and loop structures for scalability.
  • Key Findings: Demonstrated clear quantum advantages and coherence properties.

Temporal Modes of Light

Pulse Temporal Mode Encoding

  • Concept: Encoding in time-frequency phase space to achieve high-dimensional information encoding.
  • Tools: Quantum pulse gates for manipulating pulse modes.
  • Applications: Enhanced metrological accuracy, high-dimensional quantum communication, resolving incoherent emitters.
  • Experiments: Successful implementation and applications in quantum metrology, multi-parameter estimation.

Future Prospects

  • Technological Changes: Transition to LNOI platform for improved performance and scalability.
  • Experimental Developments: Integrating high-efficiency detectors, engineering for lower loss and higher coherence systems.
  • Quantum Communication: Exploring applications of pulse gate devices for secure communication.

Q&A Highlights

  • Single Photon Sources: Efficiency improvements and challenges of ensuring single photon emissions.
  • Scaling Quantum Systems: Use of different spatial and temporal modes, engineering dispersion properties for scalability.
  • Technological Integration: Combining classical and quantum communication methods using tools like quantum pulse gates.

Conclusion

  • Professor Christine Silberhorn’s lecture provided a comprehensive overview of current research and technological advancements in quantum photonics. This includes integrated optics, time-multiplexed systems, and temporal modes. She also highlighted future directions and ongoing challenges in the field.

Acknowledgments

  • Recognition of collaborative efforts within her research group.
  • Acknowledgment of funding agencies.
  • Invitation for further collaboration and participation.