Simulating Quantum Instruments with Projective Measurements and Quantum Post-Processing

This seminar talk by Shishir Khandelwal from Lund University, Sweden explores the simulation of quantum instruments using projective measurements and quantum post-processing. Dive into the connection between instrument simulability and entanglement classification problems, discovering computationally efficient necessary conditions for simulating generic instruments and complete characterization for qubits. Learn how these findings apply to important quantum information tasks including noise-tolerance of qubit unsharp measurements, non-projective advantages in information-disturbance trade-offs, and increased sequential Bell inequality violations under projective measurements. The presentation also examines d-dimensional Lüders instruments corresponding to weak versions of standard basis measurements, demonstrating how they can provide scalable noise-advantages over projective implementations at large dimensions. This 46-minute talk was presented as part of the Quantum Information and Quantum Computing Seminars at Centrum Fizyki Teoretycznej PAN on March 19, 2025.