English

Distillation with sublogarithmic overhead

Quantum Physics 2018-02-07 v2

Abstract

It has been conjectured [1] that for any distillation protocol for magic states for the TT gate, the number of noisy input magic states required per output magic state at output error rate ϵ\epsilon is Ω(log(1/ϵ))\Omega(\log(1/\epsilon)). We show that this conjecture is false. We find a family of quantum error correcting codes of parameters [[i=w+1m(mi),i=0w(mi),i=w+1r+1(r+1i)]][[\sum_{i=w+1}^m \binom{m}{i}, \sum_{i=0}^{w} \binom{m}{i}, \sum_{i=w+1}^{r+1} \binom{r+1}{i}]] for any integers m>2r m > 2r, r>w0r > w \ge 0, by puncturing quantum Reed-Muller codes. When m>νrm > \nu r, our code admits a transversal logical gate at the ν\nu-th level of Clifford hierarchy. In a distillation protocol for magic states at the level ν=3\nu = 3 (TT-gate), the ratio of input to output magic states is O(logγ(1/ϵ))O(\log^\gamma (1/\epsilon)) where γ=log(n/k)/log(d)<0.678\gamma = \log(n/k)/\log(d)< 0.678 for some m,r,wm,r,w. The smallest code in our family for which γ<1\gamma < 1 is on 258\approx 2^{58} qubits.

Keywords

Cite

@article{arxiv.1709.03543,
  title  = {Distillation with sublogarithmic overhead},
  author = {M. B. Hastings and J. Haah},
  journal= {arXiv preprint arXiv:1709.03543},
  year   = {2018}
}

Comments

2 pages. v2: fixed typo in abstract

R2 v1 2026-06-22T21:39:29.228Z