diff --git a/codes/quantum/qubits/stabilizer/qldpc/homological/hypergraph_product.yml b/codes/quantum/qubits/stabilizer/qldpc/homological/hypergraph_product.yml index 3569bf765..57f36b281 100644 --- a/codes/quantum/qubits/stabilizer/qldpc/homological/hypergraph_product.yml +++ b/codes/quantum/qubits/stabilizer/qldpc/homological/hypergraph_product.yml @@ -12,20 +12,22 @@ short_name: 'HGP' introduced: '\cite{arXiv:0903.0566,arxiv:1202.0928}' description: | - A family of \([[n,k,d]]\) CSS codes whose construction is based on two binary linear \textit{seed} codes, \(C_i=[n_i,k_i,d_i]\) with \(i\in\{1,2\}\). - Given the two seed parity-check matrices \(H_{1,2}\), the hypergraph product yields two classical codes \(C_{X,Z}\) with parity-check matrices + A family of \([[n,k,d]]\) CSS codes whose construction is based on two binary linear \textit{seed} codes, \(i\in\{1,2\}\) \(C_i\) with parameters \([n_i, k_i, d_i]\) defined as the kernel of \(r_i \times n_i\) check matrices \(H_i\) of rank \(n_i - k_i\). + The hypergraph product yields two classical codes \(C_{X,Z}\) with parity-check matrices \begin{align} - H_{X}&=\begin{pmatrix}H_{1}\otimes I_{n_{2}} & \,\,I_{n_{1}-k_{1}}\otimes H_{2}^{T}\end{pmatrix}\\ - H_{Z}&=\begin{pmatrix}I_{n_{1}}\otimes H_{2} & \,\,H_{1}^{T}\otimes I_{n_{2}-k_{2}}\end{pmatrix}~, + H_{X}&=\begin{pmatrix}H_{1}\otimes I_{n_{2}} & \,\,I_{r_{1}}\otimes H_{2}^{T}\end{pmatrix}\\ + H_{Z}&=\begin{pmatrix}I_{n_{1}}\otimes H_{2} & \,\,H_{1}^{T}\otimes I_{r_{2}}\end{pmatrix}~, \end{align} where \(I_m\) is the \(m\)-dimensional identity matrix. These two codes then yield a hypergraph product code via the CSS construction. + + # Could be expanded to include Tanner graphs # Defn of CSS has been changed to accomodate this... In contrast to the original CSS construction there are no restrictions on the form of \(C_1\) and \(C_2\).' -protection: 'The hypergraph product has distance \(d=O(\sqrt{n})\). The number of encoded logical qubits is \(k=O(k_1k_2)\) where \(k_1\) and \(k_2\) are the dimensions of the classical seed codes \(C_1\) and \(C_2\).' +protection: 'If \([n_i, k_i, d_i]\) (\([r_i, k^T_i, d^T_i]\)) are the parameters of the codes \(\mathrm{ker}H_i\) (\(\mathrm{ker}H_i^T\), taking (\(d=\infty\) if \(k=0\)), the hypergraph product has parameters \([[n_1 n_2 + r_1 r_2, k_1 k_2 + k_1^T k_2^T, \mathrm{min}(d_1, d_2, d_1^T, d_2^T)]]\)' #notes: # VVA: Added already as cousin entry. - 'The surface code can be constructed form the hypergraph product of two repetition codes. Similarily, the toric code is obtained from the hypergraph product of two closed-loop repetition codes.' @@ -41,7 +43,7 @@ features: general_gates: - 'Code deformation techniques yield Clifford gates \cite{arXiv:1909.07424}.' code_capacity_threshold: - - 'The threshold under ML decoding corresponds to the value of critical point of a two-dimensional random-bond Ising model on the Nishimori line \cite{doi:10.1143/JPSJ.55.3305,arxiv:quant-ph/0110143,arxiv:1804.01950} (see also \cite{arxiv:2301.05689}).' + - '\cite{doi:10.1103/PhysRevA.87.020304,doi:10.1143/JPSJ.55.3305,arxiv:quant-ph/0110143,arxiv:1804.01950} (see also \cite{arxiv:2301.05689}).' threshold: - 'Circuit-level noise: \(0.1\%\) with all-to-all connected syndrome extraction circuits \cite{arxiv:2109.14599}. No threshold observed above physical noise rates at or above \(10^{-6}\) using 2D geometrically local syndrome extraction circuits.' @@ -62,6 +64,8 @@ relations: _meta: # Change log - most recent first changelog: + - user_id: ChrisPattison + date: '2023-10-25' - user_id: VictorVAlbert date: '2022-08-02' - user_id: VictorVAlbert