CCSP Seminar: Narayanan Rengaswamy, "Mitigating Coherent Noise in Quantum Computing"
Communication, Control and Signal Processing Seminar
Mitigating Coherent Noise in Quantum Computing using the Classical MacWilliams Identities
University of Arizona
Zoom link: https://umd.zoom.us/j/96099437335
Noise in quantum systems can be coherent or stochastic (incoherent). The former is more damaging since such noise can accumulate in one direction and grow quadratically in the number of qubits. While standard quantum error correction (QEC) addresses noise actively by measuring syndromes and applying corrections, we develop conditions for a stabilizer code to passively tackle coherent noise. When the noise introduces a coherent Z-rotation by an angle theta on all qubits, our codes remain unaffected and act as a decoherence free subspace (DFS). Given any [[n,k,d]] stabilizer code and even M, we can produce a [[Mn,k,>= d]] code that is a DFS for this noise.