Time：September 8 2021, 10:30-11:30

ZOOM Meeting ID: 775 921 8510 (Passcode: Quantum)

Title：Tailor-made quantum error correction codes: Coherent error avoiding codes and permutation-invariant codes

Host：Dong Liu, Research Scientist, BAQIS；Associate Professor, Department of Physics, Tsinghua University 

Abstract：

This talk comprises of two parts. 

Part I: Coherent errors, which arise from collective couplings, are a dominant form of noise in many realistic quantum systems,and are more damaging than oft considered stochastic errors. Here, we propose a simple strategy of integrating stabilizer codes with constantexcitation codes by code concatenation to completely avoid coherent errors. Namely, we can concatenate an [[n,k,d]] stabilizer outer code with dual-rail inner codes, to obtain a [[2n,k,d]] constant-excitation code immune from coherent phase errors.

Part II: 

Permutation-invariant  quantum codes are invariant under any permutation of the underlying particles.  These codes could have potential applications in quantum sensors and quantum memories.  Here I will review the field of permutation-invariant codes, from code constructions to applications

About the Speaker：Yingkai Ouyang received his Ph.D. degree in Combinatorics and Optimization from the University of Waterloo in 2013. He did postdocs in Singapore and Sheffield, UK, and is currently at the National University of Singapore. His research interest lies in quantum error correction and intersections with quantum metrology, quantum computation and other aspects of quantum information theory.