Our guest Falk Ludwig from University of Cambridge, UK, will give a talk:
Title:
Fault-Tolerant Quantum Computation and Transversality
Abstract:
Reliable quantum computation in the circuit model requires careful use of quantum error correction codes on ancillary qubits countering decoherence of sensitive quantum systems (qubits). Concatenation of such encoding gives the threshold theorem which allows for fault-tolerance given the noise rate is bound below a constant. Concatenated codes result in a polylogarithmically large ratio between physical and logical qubits (space overhead) in the depth of the circuit. For special constant rate low-density parity-check (LDPC) codes a constant space overhead in large computations and polynomial time can be achieved. Among other qualities, fault tolerance seeks codes with sets of gates that have computational universality but also transversality, a property which keeps error propagation under control and simplifies implementation. Following Eastin and Knill, universality and transversality pose a mutual exclusivity to be circumvented.
We inspect these schemes that make fault-tolerant quantum computation feasible and identify standing prospects as well as limitations. I aim to follow with an investigation of the role of transversal gates, their relation to possible overhead bounds and an evaluation of open challenges and alternative approaches.
Everybody is cordially invited to attend.
Falk Ludwig, University of Cambridge, UK