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Volume 45 Issue 5
May  2023
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Wu Yingliang, Wei Gang, Li Haizhou. A WORD SEGMENTATION ALGORITHM FOR CHINESE LANGUAGE BASED ON N-GRAM MODELS AND MACHINE LEARNING[J]. Journal of Electronics & Information Technology, 2001, 23(11): 1148-1153.
Citation: WANG Yu, KAI Xiaoshan, ZHU Shixin. A Construction Method of Quantum Error-correcting Codes over ${\boldsymbol F_{{2^m}}}$[J]. Journal of Electronics & Information Technology, 2023, 45(5): 1731-1736. doi: 10.11999/JEIT221145

A Construction Method of Quantum Error-correcting Codes over ${\boldsymbol F_{{2^m}}}$

doi: 10.11999/JEIT221145
Funds:  The National Natural Science Foundation of China (12171134, U21A20428), The Key Project of Support Program for Outstanding Young Talents in University of Anhui Province (gxyqZD2021137)
  • Received Date: 2022-09-01
  • Rev Recd Date: 2022-11-27
  • Available Online: 2022-12-02
  • Publish Date: 2023-05-10
  • Constructing quantum codes with good parameters is an important part of quantum error-correcting codes research. In this paper, $ {2^m} $-ary quantum codes are derived through Hermitian dual-containing constacyclic codes over finite non-chain ring $ R = {F_{{4^m}}} + v{F_{{4^m}}} $. A new Gray map $ \phi $ is defined, which is Hermitian dual-containing preserving from a linear code C over R to $ \phi (C) $. The condition for constacyclic codes over R to be Hermitian dual-containing is studied. A method of constructing $ {2^m} $-ary quantum codes is presented, and some new 4-ary and 8-ary quantum codes are obtained.
  • 量子纠错码在量子通信和量子计算领域具有非常重要的应用。因此,构造具有良好参数的量子纠错码成为编码理论领域的一个研究热点。CSS构造[1]和厄米特构造[2]是利用经典纠错码构造量子纠错码的两种常用方法。研究表明,有限域上的循环码及常循环码是构造好量子码的重要来源[3-5]。文献[6]首次通过有限环上的循环码来构造二元量子码,利用的是链环$ {F_2} + u{F_2} $。之后,有限非链环上的循环码也被证实可以产生新的量子码,如环$ {F_2} + v{F_2} $[7]$ {F_p} + v{F_p} $[8]等。近年来,有限环上的常循环码成为量子码构造的新途径。文献[9]利用CSS构造,通过环$ {F_p} + u{F_p} $上的常循环码构建$ p $元量子码。文献[10,11]将这种方法推广到了两类更一般的有限交换非链环上。文献[12]采用厄米特构造,通过环$ {F_{{q^2}}} + v{F_{{q^2}}} $上的常循环码得到了一类$ q $元量子MDS码。文献[13,14]分别利用环${F_{{q^2}}} + u{F_{{q^2}}} + \cdots + {u^{r - 1}}{F_{{q^2}}}$$ {F_{{q^2}}} + {u_1}{F_{{q^2}}} + \cdots + {u_r}{F_{{q^2}}} $上的常循环码获取了新的$ q $元量子码。文献[15]利用链环$ {F_{{2^{2m}}}} + u{F_{{2^{2m}}}} $上的厄米特对偶包含常循环码来构建$ {2^m} $元量子码。

    截至目前,有限环上常循环码相关文献中构造的量子码主要是二元[6,7]$ p $[8-10]$ {p^m} $[11-14]($ p $为奇素数),构造$ {2^m} $元量子码的研究还较为少见。本文通过非链环$ R = {F_{{4^m}}} + v{F_{{4^m}}} $上的常循环码来构造$ {2^m} $元量子码。首先定义了一个从环$ R $到域$ {F_{{4^m}}} $上的新Gray映射,然后确定了环$ R $上常循环码为厄米特对偶包含码的条件,最后给出了一种构造$ {2^m} $元量子码的新方法,并例举了一些新的4元和8元量子码。

    $ {F_{{4^m}}} $$ {4^m} $元有限域,$ m $为正整数。令$R = {F_{{4^m}}} + v{F_{{4^m}}} = \{ a + vb|a,b \in {F_{{4^m}}}\}$,其中$ {v^2} = v $。容易验证,$ R $是一个有限非链环,且具有极大理想$ \langle 1 + v\rangle $$ \langle v\rangle $$ {R^n} $$ R $-子模$ C $称为环$ R $上长为$ n $的线性码。记

    Cv={aFn4m|bFn4m,(1+v)a+vbC},C1+v={bFn4m|aFn4m,(1+v)a+vbC}
    (1)

    $ {C_v} $$ {C_{1 + v}} $都是有限域$ {F_{{4^m}}} $上长为$ n $的线性码,且线性码$ C $可以唯一分解表示为$ C = (1 + v){C_v} \oplus v{C_{1 + v}} $。设线性码$ {C_v} $$ {C_{1 + v}} $的生成矩阵分别为$ {{\boldsymbol {G}}_1} $$ {{\boldsymbol {G}}_2} $,则线性码$ C $具有生成矩阵$ {\boldsymbol {G}} = \left( {(1+v)G1vG2

    } \right) $

    $ C $是环$ R $上长为$ n $的线性码,$ \lambda = \alpha + v\beta $是环$ R $的一个单位。若对任意$ ({c_0},{c_1}, \cdots ,{c_{n - 1}}) \in C $,都有$ (\lambda {c_{n - 1}},{c_0}, \cdots ,{c_{n - 2}}) \in C $,则称$ C $为环$ R $上的$ \lambda $-常循环码。将码字$ {\boldsymbol {c}} = ({c_0},{c_1}, \cdots ,{c_{n - 1}}) $等同于其多项式表示$ c(x) = {c_0} + {c_1}x + \cdots + {c_{n - 1}}{x^{n - 1}} $,则环$ R $上长为$ n $$ \lambda $-常循环码可视为商环$ R[x]/\langle {x^n} - \lambda \rangle $的一个理想。

    $ \forall \alpha \in {F_{{4^m}}} $,记$ \alpha $的共轭$ {\alpha ^{{2^m}}} $$ \bar \alpha $。环$ R $中元素$ \lambda = \alpha + v\beta $的共轭定义为$ \bar \lambda = \bar \alpha + v\bar \beta $。任取两个$ n $维向量$ {\boldsymbol {x}} = ({x_0},{x_1}, \cdots ,{x_{n - 1}}) $${\boldsymbol {y}} = ({y_0},{y_1}, \cdots ,{y_{n - 1}}) \in {R^n}$,其厄米特内积定义为

    x,yH=x0ˉy0+x1ˉy1++xn1ˉyn1
    (2)

    $ C $是环$ R $上长为$ n $的线性码,其厄米特对偶码定义为$ {C^{{ \bot _H}}} = \{ {\boldsymbol {x}} \in {R^n}|{\langle {\boldsymbol {x}},{\boldsymbol {y}}\rangle _H} = 0,\forall {\boldsymbol {y}} \in C\} $。若$ {C^{{ \bot _H}}} \subseteq C $,则称$ C $为厄米特对偶包含码。利用有限域上的厄米特对偶包含码可以构造量子码,其方法如下。

    定理1[2](厄米特构造) 设$ \mathfrak{C} $是一个有限域$ {F_{{q^2}}} $上参数为$ [n,k,d] $的厄米特对偶包含码,则存在一个参数为${[[n,2k - n, \ge d]]_q}$的量子码。

    下面定义一个从环$ R $$ F_{{4^m}}^2 $的Gray映射$ \phi $,并证明:如果$ C $是环$ R $上的厄米特对偶包含码,那么$ \phi (C) $是有限域$ {F_{{4^m}}} $上的厄米特对偶包含码。

    定义1 设$ \omega $是有限域$ {F_{{4^m}}} $的一个本原元,记$ \bar \omega = {\omega ^{{2^m}}} $。定义Gray映射

    ϕ:RF24m
    (1+v)x+vy(x+ˉωy,ωx+y)
    (3)

    容易验证,当$ m > 1 $时,$ \phi $是一个双射。可以自然地将它推广到$ \phi :{R^n} \to F_{{4^m}}^{2n} $,即

    (c0,c1,,cn1)(r0+ˉωq0,r1+ˉωq1,,rn1+ˉωqn1,ωr0+q0,ωr1+q1,,ωrn1+qn1)
    (4)

    其中,$ {c_i} = (1 + v){r_i} + v{q_i},i = 0,1, \cdots ,n - 1 $

    $ \forall a \in R $,定义$ a $的Gray重量为$ \phi (a) $的汉明重量,即$ {w_G}(a) = {w_H}(\phi (a)) $。向量${\boldsymbol {x}} = ({x_0},{x_1}, \cdots , {x_{n - 1}}) \in {R^n}$的Gray重量为$ {w_G}({\boldsymbol {x}}) = {w_H}(\phi ({\boldsymbol {x}})) $$ {R^n} $中向量$ {\boldsymbol {x}} $$ {\boldsymbol {y}} $的Gray距离定义为${d_G}({\boldsymbol {x}},{\boldsymbol {y}}) = {w_G}({\boldsymbol {x}} - {\boldsymbol {y}})$。定义环$ R $上线性码$ C $的极小Gray距离为$ {d_G}(C) = \min \{ {d_G}({\boldsymbol {c}},{\boldsymbol {c'}})|{\boldsymbol {c}},{\boldsymbol {c'}} \in C,{\boldsymbol {c}} \ne {\boldsymbol {c'}}\} $

    根据上述定义,可以得到如下结论:

    命题1 设$ C $是环$ R $上长为$ n $的线性码,则$ \phi (C) $是有限域$ {F_{{4^m}}} $上长为$ 2n $的线性码。映射$ \phi $是从$ C $(Gray距离)到$ \phi (C) $(汉明距离)的保矩映射。

    证明 对$ \forall {k_1},{k_2} \in {F_{{4^m}}} $$ {\boldsymbol {x}},{\boldsymbol {y}} \in {R^n} $,易证得$ \phi ({k_1}{\boldsymbol {x}} + {k_2}{\boldsymbol {y}}) = {k_1}\phi ({\boldsymbol {x}}) + {k_2}\phi ({\boldsymbol {y}}) $。因此,$ \phi (C) $是有限域$ {F_{{4^m}}} $上长为$ 2n $的线性码。任取$ {\boldsymbol {c}},{\boldsymbol {c'}} \in C $, ${d_G}({\boldsymbol {c}},{\boldsymbol {c'}}) = {w_G}({\boldsymbol {c}} - {\boldsymbol {c'}})$ = ${w_H}(\phi ({\boldsymbol {c}} - {\boldsymbol {c'}})) = {w_H}(\phi ({\boldsymbol {c}}) - \phi ({\boldsymbol {c'}})) = {d_H}(\phi ({\boldsymbol {c}}),\phi ({\boldsymbol {c'}}))$,因此,$ \phi $是从$ C $(Gray距离)到$ \phi (C) $(汉明距离)的保矩映射。 证毕

    命题2 设$ C = (1 + v){C_v} \oplus v{C_{1 + v}} $是环$ R $上长为$ n $的线性码,$ {d_G} $$ C $的极小Gray距离,线性码$ {C_v},{C_{1 + v}} $的维数分别为$ {k_1},{k_2} $,生成矩阵为$ {{\boldsymbol {G}}_1},{{\boldsymbol {G}}_2} $,则$ \phi (C) $具有参数$ {[2n,{k_1} + {k_2},{d_G}]_{{4^m}}} $和生成矩阵$ \left( {G1ωG1ˉωG2G2

    } \right) $

    证明 由命题1知,$ \phi (C) $具有码长$ 2n $和极小汉明距离$ {d_G} $。因为$|\phi (C)| = |C| = |{C_v}| \cdot |{C_{1 + v}}| = {({4^m})^{{k_1} + {k_2}}}$,所以$ \phi (C) $具有维数$ {k_1} + {k_2} $。又因为$ C $具有生成矩阵$ \left( {(1+v)G1vG2

    } \right) $,所以$ \phi (C) $具有生成矩阵

    $ \left( {ϕ((1+v)G1)ϕ(vG2)

    } \right) = \left( {G1ωG1ˉωG2G2
    } \right) $ 证毕

    注 从生成矩阵可以看出,$ \phi (C) $的极小距离${d_G} \le \min \{ 2{d_H}({C_v}),2{d_H}({C_{1 + v}})\}$,而在非链环${F_q} + v{F_q}({v^2} = v)$上常用Gray映射$\varphi :a + vb \to (a,a + b)$的作用下,$ {d_H}(\varphi (C)) = \min \{ {d_H}({C_v}),{d_H}({C_{1 + v}})\} $。对比发现,本文定义的Gray映射能够提高Gray像的极小距离,这对构造参数好的量子码具有重要的意义。

    定理2 设$ C $是环$ R $上长为$ n $的线性码,则$ \phi ({C^{{ \bot _H}}}) = \phi {(C)^{{ \bot _H}}} $。特别地,若$ {C^{{ \bot _H}}} \subseteq C $,则$\phi {(C)^{{ \bot _H}}} \subseteq \phi (C)$

    证明 任取$ {{\boldsymbol {c}}_1} = (1 + v){{\boldsymbol {r}}_1} + v{{\boldsymbol {q}}_1} \in C $, ${{\boldsymbol {c}}_2} = (1 + v){{\boldsymbol {r}}_2} + v{{\boldsymbol {q}}_2} \in {C^{{ \bot _H}}}$,其中$ {{\boldsymbol {r}}_1},{{\boldsymbol {r}}_2},{{\boldsymbol {q}}_1},{{\boldsymbol {q}}_2} \in F_{{4^m}}^n $,则

    c1,c2H=((1+v)r1+vq1)((1+v)ˉr2+vˉq2)=(1+v)r1ˉr2+vq1ˉq2
    (5)

    因为$ {\langle {{\boldsymbol {c}}_1},{{\boldsymbol {c}}_2}\rangle _H} = 0 $,所以$ {{\boldsymbol {r}}_1}{{\boldsymbol {\bar r}}_2} = 0 $$ {{\boldsymbol {q}}_1}{{\boldsymbol {\bar q}}_2} = 0 $。因此

    ϕ(c1),ϕ(c2)H=ϕ(c1)¯ϕ(c2)=(r1+ˉωq1)(ˉr2+ωˉq2)+(ωr1+q1)(ˉωˉr2+ˉq2)=(1+ωˉω)r1ˉr2+(1+ωˉω)q1ˉq2=0
    (6)

    这表明$ \phi ({C^{{ \bot _H}}}) \subseteq \phi {(C)^{{ \bot _H}}} $。另外,

    |ϕ(CH)|=|CH|=|R|n|C|=(4m)2n|ϕ(C)|=|ϕ(C)H|
    (7)

    因此,$ \phi ({C^{{ \bot _H}}}) = \phi {(C)^{{ \bot _H}}} $。 特别地,若$ {C^{{ \bot _H}}} \subseteq C $,则$ \phi {(C)^{{ \bot _H}}} = \phi ({C^{{ \bot _H}}}) \subseteq \phi (C) $证毕

    $ C = (1 + v){C_v} \oplus v{C_{1 + v}} $是环$ R $上长为$ n $的线性码,$ \lambda = \alpha + v\beta = (1 + v)\alpha + v(\alpha + \beta ) $是环$ R $的一个单位,其中$ \alpha ,\beta \in {F_{{4^m}}} $。文献[16]给出了环$ {F_{{q^2}}} + v{F_{{q^2}}} $上常循环码的一些基本性质,$ q $为素数方幂。令其中$ q = {2^m} $,可以直接得到下面两个结论。

    命题3 $ C $是环$ R $上的$ \lambda $-常循环码当且仅当$ {C_v} $是域$ {F_{{4^m}}} $上的$ \alpha $-常循环码,$ {C_{1 + v}} $是域$ {F_{{4^m}}} $上的$ (\alpha + \beta ) $-常循环码。

    命题4 设$ C $是环$ R $上的$ \lambda $-常循环码,则$ {C^{{ \bot _H}}} = (1 + v)C_v^{{ \bot _H}} \oplus vC_{1 + v}^{{ \bot _H}} $,其中$ C_v^{{ \bot _H}} $$ C_{1 + v}^{{ \bot _H}} $分别是域$ {F_{{4^m}}} $上的$ {\alpha ^{ - {2^m}}} $-常循环码和$ {(\alpha + \beta )^{ - {2^m}}} $-常循环码。

    从命题4容易得出:

    引理1 设$ C $是环$ R $上的$ \lambda $-常循环码,则$ {C^{{ \bot _H}}} \subseteq C $的充分必要条件是$ C_v^{{ \bot _H}} \subseteq {C_v} $$ C_{1 + v}^{{ \bot _H}} \subseteq {C_{1 + v}} $

    由命题3、命题4及引理1易知,满足$ {C^{{ \bot _H}}} \subseteq C $的必要条件是$ {\alpha ^{ - {2^m}}} = \alpha $$ {(\alpha + \beta )^{ - {2^m}}} = \alpha + \beta $,即$ {C^{{ \bot _H}}} $也是环$ R $上的$ \lambda $-常循环码。

    引理2 设$ C $是环$ R $上的$ \lambda $-常循环码,$ \omega $是有限域$ {F_{{4^m}}} $的一个本原元。令$\alpha = {\omega ^{{\mu _1}({2^m} - 1)}}, \alpha + \beta = {\omega ^{{\mu _2}({2^m} - 1)}}$,其中$ {\mu _1},{\mu _2} \in \{ 0,1, \cdots ,{2^m}\} $,则$ {C^{{ \bot _H}}} $也是环$ R $上的$ \lambda $-常循环码。

    证明 因为$ {\omega ^{{4^m}}} = \omega $,所以${\alpha ^{ - {2^m}}} = {\omega ^{{\mu _1}( - {4^m} + {2^m})}} = {\omega ^{{\mu _1}({2^m} - 1)}} = \alpha$。类似地,可以证明${(\alpha + \beta )^{ - {2^m}}} = \alpha + \beta$。由命题4和命题3知,$ {C^{{ \bot _H}}} $也是环$ R $上的$ \lambda $-常循环码。 证毕

    接下来补充一个有限域$ {F_{{q^2}}} $($ q $为素数方幂)上厄米特对偶包含常循环码的结论。设$ \mathfrak{C} = \langle g(x)\rangle $是有限域$ {F_{{q^2}}} $上长为$ n $$ \eta $-常循环码,$ {\text{or}}{{\text{d}}_{{q^2}}}(\eta ) = r $$ \gcd (q,n) = 1 $,则存在一个$ rn $次本原单位根$ \delta $使得$ {\delta ^n} = \eta $,即${x^n} - \eta = \displaystyle\prod\nolimits_{i = 0}^{n - 1} {(x - {\delta ^{1 + ir}})}$。令$\varOmega = \{ 1 + ir|0 \le i \le n - 1\} n - 1\}$,对每个$j \in \varOmega$,记$ C_j^{rn} $为包含$ j $$ {q^2} $-模$ rn $的分圆陪集。称集合$Z = \{ j \in \varOmega |g({\delta ^j}) = 0\}$为常循环码$ \mathfrak{C} $的定义集,它是一些分圆陪集$ C_j^{rn} $的并集。

    引理3[3]$ \mathfrak{C} $是有限域$ {F_{{q^2}}} $上长为$ n $$ \eta $-常循环码,其定义集为$ Z $。若$ {\mathfrak{C}^{{ \bot _H}}} $也是一个$ \eta $-常循环码,则$ {\mathfrak{C}^{{ \bot _H}}} \subseteq \mathfrak{C} $当且仅当$Z \cap {Z^{ - q}} =\varnothing$,其中${Z^{ - q}} = \{ - qj{\text{ }}\bmod rn|j \in Z\}$

    根据引理1—引理3,可以得到环$ R $上常循环码是厄米特对偶包含码的一个判定条件。

    定理3 设$ C $是环$ R $上长为$ n $$ \lambda $-常循环码,$ \alpha = {\omega ^{{\mu _1}({2^m} - 1)}},\alpha + \beta = {\omega ^{{\mu _2}({2^m} - 1)}} $${\mu _1},{\mu _2} \in \{ 0,1, \cdots , {2^m}\}$。设$ {Z_1} $$ {Z_2} $分别是域$ {F_{{4^m}}} $上常循环码$ {C_v} $$ {C_{1 + v}} $的定义集,则$ {C^{{ \bot _H}}} \subseteq C $当且仅当${Z_i} \cap {Z_i}^{ - {2^m}} = \varnothing ,{\text{ }}i = 1,2$,其中$ {Z_i}^{ - {2^m}} = \{ - {2^m}j{\text{ }}\bmod {r_i}n|j \in {Z_i}\} $, $ {r_1} = {\text{or}}{{\text{d}}_{{4^m}}}(\alpha ) $$ {r_2} = {\text{or}}{{\text{d}}_{{4^m}}}(\alpha + \beta ) $

    证明 由引理2知,当$ \alpha = {\omega ^{{\mu _1}({2^m} - 1)}} $$ \alpha + \beta = {\omega ^{{\mu _2}({2^m} - 1)}} $时,$ C_v^{{ \bot _H}} $是域$ {F}_{{4}^{m}} $上的$ \alpha $-常循环码,$ C_{1 + v}^{{ \bot _H}} $是域$ {F_{{4^m}}} $上的$ (\alpha + \beta ) $-常循环码。根据引理3,此时$ C_v^{{ \bot _H}} \subseteq {C_v} $$ {C}_{1+v}^{{\perp }_{H}}\subseteq {C}_{1+v} $当且仅当${Z_i} \cap {Z_i}^{ - {2^m}} = \varnothing$。再由引理1及等价的传递性可知,$ {C^{{ \bot _H}}} \subseteq C $当且仅当${Z_i} \cap {Z_i}^{ - {2^m}} = \varnothing$证毕

    $ \lambda = (1 + v)\alpha + v(\alpha + \beta ) $,且$ \alpha = {\omega ^{{\mu _1}({2^m} - 1)}} $$ \alpha + \beta = {\omega ^{{\mu _2}({2^m} - 1)}} $$ {\mu }_{1},{\mu }_{2}\in \{0,1,\cdots ,{2}^{m}\} $。根据定理1—定理3,本节给出一种利用环$ R $$ \lambda $-常循环码来构造$ {2^m} $元量子码的方法,具体如下:

    定理4 设$ C=(1+v){C}_{v}\oplus v{C}_{1+v} $是环$ R $上长为$ n $$ \lambda $-常循环码,$ {Z}_{1} $$ {Z_2} $分别是码$ {C_v} $$ {C_{1 + v}} $的定义集,若对$ i = 1,2 $都有$ {Z_i} \cap {Z_i}^{ - {2^m}} = \varnothing $成立,则存在一个参数为$ {[[2n,2k - 2n, \ge d]]_{{2^m}}} $的量子码,其中$ k $$ d $分别为线性码$ \phi (C) $的维数和极小汉明距离。

    证明 根据定理3,若对$ i = 1,2 $都有${Z_i} \cap {Z_i}^{ - {2^m}} = \varnothing$成立,则$ {C^{{ \bot _H}}} \subseteq C $。再由定理2可得$ \phi {(C)^{{ \bot _H}}} \subseteq \phi (C) $,即$ \phi (C) $是有限域$ {F_{{4^m}}} $上的厄米特对偶包含码。又因为$ \phi (C) $具有参数$ {[2n,k,d]_{{4^m}}} $,由定理1知,存在一个参数为$ {[[2n,2k - 2n, \ge d]]_{{2^m}}} $的量子码。 证毕

    下面通过两个具体的例子来解释定理4中的构造方法。

    例1 设$m = 2,\;n = 17,\;{\mu _1} = 0,\;{\mu _2} = 1$,则$ \alpha = {\omega ^0} = 1,{\text{ }}\alpha + \beta = {\omega ^3} $,即$ C $是环$ R = {F_{{4^2}}} + v{F_{{4^2}}} $上长为$ 17 $$ (1 + v + v{\omega ^3}) $-常循环码。易知${{\rm{ord}}_{{4^2}}}(\alpha ) = 1,{\text{ }}{{\rm{ord}}_{{4^2}}}(\alpha + \beta ) = 5$。设${Z_1} = C_1^{17} = \{ 1,\;16\} , \;{\text{ }}{Z_2}\; =\; C_1^{85}\; \cup\; C_6^{85}$ $ =\; \{ 1,16,6,11\} $,则${C_v} = \langle {g_1}(x)\rangle = \langle {x^2} + {\omega ^3}x + 1\rangle$, ${C_{1 + v}} = \langle {g_2}(x)\rangle = \langle ({x^2} + {\omega ^2}x + {\omega ^3}) ({x^2} + {\omega ^3}x + {\omega ^3})\rangle$。此外,$Z_1^{ - 4} = \{ 13,4\}$$Z_2^{ - 4} = \{ 81,21,61,41\}$。因此对$ i = 1,2 $${Z_i} \cap {Z_i}^{ - 4} = \varnothing$。由命题2知,$ \phi (C) $具有码长34和维数28。借助MAGMA软件,通过命题2中生成矩阵可以计算出$ \phi (C) $的极小汉明距离为5。因此,$ \phi (C) $具有参数$ {[34,28,5]_{{4^2}}} $。根据定理4,可以构造出一个参数为$ {[[34,22, \ge 5]]_4} $的新量子码。类似地,利用环$R = {F_{{4^2}}} + v{F_{{4^2}}}$上长为$ 17 $$ (1 + v + v{\omega ^3}) $-常循环码,通过选择不同的定义集,可以得到多个码长为34的4元新量子码,如表1所示,其中生成多项式$ {x^k} + {a_1}{x^{k - 1}} + \cdots + {a_{k - 1}}x + {a_k} $被简记为$ 1{a_1} \cdots {a_k} $

    表  1  码长为34的新的4元量子码
    $ {g_1}(x) $$ {g_2}(x) $$ \phi (C) $$ {[[n,k,d]]_4} $
    $ 1{\omega ^3}1 $$ (1{\omega ^2}{\omega ^3})(1{\omega ^3}{\omega ^3}) $[34,28,5]16[[34,22,$ \ge $5]]4
    $ (1{\omega ^3}1)(1{\omega ^6}1) $$ (1{\omega ^2}{\omega ^3})(1{\omega ^3}{\omega ^3}) $[34,26,6]16[[34,18,$ \ge $6]]4
    $ (1{\omega ^3}1)(1{\omega ^6}1) $$ (1{\omega ^3}{\omega ^3})(1{\omega ^{11}}{\omega ^3})(1{\omega ^{13}}{\omega ^3}) $[34,24,7]16[[34,14,$ \ge $7]]4
    $ (1{\omega ^3}1)(1{\omega ^6}1)(1\omega 1) $$ (1{\omega ^3}{\omega ^3})(1{\omega ^{11}}{\omega ^3})(1{\omega ^{13}}{\omega ^3}) $[34,22,8]16[[34,10,$ \ge $8]]4
    $ (1{\omega ^3}1)(1{\omega ^6}1)(1\omega 1) $$ (1{\omega ^3}{\omega ^3})(1{\omega ^{11}}{\omega ^3})(1{\omega ^{13}}{\omega ^3})(1{\omega ^6}{\omega ^3}) $[34,20,9]16[[34,6,$ \ge $9]]4
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    注 从极小距离$ d $和码率$\dfrac{k}{n}$两个方面,将表1中量子码与通用量子码表文献[17]中相近长度的最优量子码参数进行比较,可以发现:$ {[[34,22, \ge 5]]_4} $比文献[17]中的$ {[[33,21,4]]_4} $$ {[[36,22,4]]_4} $具有更好的参数;$ {[[34,18, \ge 6]]_4} $比文献[17]中的$ {[[33,13,5]]_4} $$ {[[32,15,6]]_4} $参数更好;$ {[[34,14, \ge 7]]_4} $$ {[[34,10, \ge 8]]_4} $分别比文献[17]中的$ {[[32,10,7]]_4} $$ {[[33,6,8]]_4} $的码率更大;$ {[[34,6, \ge 9]]_4} $比文献[17]中的$ {[[40,2,8]]_4} $具有更好的参数。

    例2 设$ m = 3,n = 35,{\mu _1} = 0,{\mu _2} = 3 $,则$\alpha \;=\; {\omega ^0} \;=\; 1,{\text{ }}\alpha + \beta \;=\; {\omega ^{21}}$,即$ C $是环$R \;=\; {F_{{4^3}}} \;+ v{F_{{4^3}}}$上长为$ 35 $$ (1 + v + v{\omega ^{21}}) $-常循环码。易知$ {\text{or}}{{\text{d}}_{{4^3}}}(\alpha ) = 1,{\text{ or}}{{\text{d}}_{{4^3}}}(\alpha + \beta ) = 3 $。设${Z_1} = C_5^{35} \cup C_6^{35} = \{ 5,6,34\} ,$$ {Z_2} = C_{10}^{105} $ $ = \{ 10\} $,则${C_v} = \langle {g_1}(x)\rangle = \langle (x + {\omega ^9})({x^2} + {\omega ^{57}}x + {\omega ^9})\rangle$${C_{1 + v}} = \langle {g_2}(x)\rangle = \langle x + {\omega ^6}\rangle$。此外,$ Z_1^{ - 8} = \{ 30,22,8\} $$ Z_2^{ - 8} = \{ 25\} $。因此对$ i = 1,2 $${Z_i} \cap {Z_i}^{ - 8} = \varnothing$。由命题2知,$ \phi (C) $具有码长70和维数66。借助MAGMA 软件,通过命题2中生成矩阵可以计算出$ \phi (C) $的极小汉明距离为$ 4 $。因此,$ \phi (C) $具有参数$ {[70,66,4]_{{8^2}}} $。根据定理4,可以构造出一个参数为$ {[[70,62, \ge 4]]_8} $的新量子码,它比量子码表文献[17]中的$ {[[70,46,3]]_8} $具有更大的极小距离和维数。

    表2表3分别利用环$ {F_{{4^2}}} + v{F_{{4^2}}} $$ {F_{{4^3}}} + v{F_{{4^3}}} $上长为$ n $的常循环码构造出一些不同长度的4元和8元新量子码。与量子码表文献[17]及文献[15]中的量子码相比,它们具有更大的码率或者极小距离,即参数更优。特别地,表中量子码$ {[[6,2,3]]_4} $, $ {[[10,2,5]]_8} $, $ {[[14,10,3]]_8} $, $ {[[14,8,4]]_8} $, $ {[[42,38,3]]_8} $为量子MDS码(量子码参数$ {[[n,k,d]]_q} $必须满足$ 2d \le n - k + 2 $,使等式成立的量子码称为量子MDS码)。此外,量子码$ {[[30,24, \ge 3]]_4} $, $ {[[34,26, \ge 4]]_4} $, $ {[[70,62, \ge 4]]_8} $, $[[98, 92, \ge 3]]_8$, $ {[[126,118, \ge 4]]_8} $的参数满足$ 2d \ge n - k $。考虑到当$ n > {q^2} + 2 $时,量子MDS码不存在,因此这些码的参数也是最优的。

    表  2  新的4元量子码
    $ n $$ \lambda $$ {g_1}(x) $$ {g_2}(x) $$ \phi (C) $$ {[[n,k,d]]_4} $$ {[[n',k',d']]_4} $
    3$ 1 + v + v{\omega ^3} $$ 1{\omega ^5} $$ 1\omega $$ {[6,4,3]_{16}} $$ {[[6,2,3]]_4} $MDS
    7$ 1 + v + v{\omega ^3} $$ 1011 $$ 1{\omega ^9}0{\omega ^{12}} $$ {[14,8,6]_{16}} $$ {[[14,2, \ge 6]]_4} $$ {[[14,0,4]]_4}{\text{ }}$[15]
    11$ 1 + v + v{\omega ^3} $$ 1{\omega ^5}11{\omega ^{10}}1 $$ 1{\omega ^8}{\omega ^6}{\omega ^9}{\omega ^7}1 $$ {[22,12,7]_{16}} $$ {[[22,2, \ge 7]]_4} $${[[24,0,6]]_4}$[17]
    15$ 1 $$ (1\omega )(1{\omega ^2}) $$ 1{\omega ^4} $$ {[30,27,3]_{16}} $$ {[[30,24, \ge 3]]_4} $$ {[[31,21,3]]_4} $[17]
    17$ 1 $$ 1{\omega ^3}1 $$ 1{\omega ^6}1 $$ {[34,30,4]_{16}} $$ {[[34,26, \ge 4]]_4} $$ {[[34,24,4]]_4} $[15]
    19$ 1 + v + v{\omega ^3} $$ 1{\omega ^{10}}0{\omega ^{10}}{\omega ^{10}}{\omega ^5}{\omega ^5}{\omega ^5}1 $$ 1{\omega ^7}0\omega {\omega ^{13}}{\omega ^5}{\omega ^2}{\omega ^{11}}{\omega ^8} $$ {[38,20,11]_{16}} $$ {[[38,2, \ge 11]]_4} $$ {[[40,2,8]]_4} $[17]
    45$ 1 $$ (1\omega )(100{\omega ^4}) $$ (1{\omega ^2})(100{\omega ^5}) $$ {[90,82,4]_{16}} $$ {[[90,74, \ge 4]]_4} $$ {[[90,66,4]]_4} $[17]
    63$ 1 + v + v{\omega ^3} $$ 111{\omega ^5} $$ 1\omega $$ {[126,122,3]_{16}} $$ {[[126,118, \ge 3]]_4} $$ {[[127,113,3]]_4} $[17]
    77$ 1 $$ 1{\omega ^5}11{\omega ^{10}}1 $$ 1011 $$ {[154,146,4]_{16}} $$ {[[154,138, \ge 4]]_4} $$ {[[154,128,4]]_4} $[17]
    85$ 1 $$ (1{\omega ^2}{\omega ^3})(1{\omega ^4}{\omega ^6}) $$ (1{\omega ^9}{\omega ^9})(1{\omega ^8}{\omega ^{12}}) $$ {[170,162,4]_{16}} $$ {[[170,154, \ge 4]]_4} $$ {[[171,151,4]]_4} $[17]
    91$ 1 + v + v{\omega ^3} $$ 1{\omega ^4}{\omega ^{13}}1 $$ (1{\omega ^3}{\omega ^8}{\omega ^9})(1{\omega ^7}{\omega ^4}{\omega ^9}) $$ {[182,173,5]_{16}} $$ {[[182,164, \ge 5]]_4} $$[[185,149,5]]_4$[17]
    下载: 导出CSV 
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    表  3  新的8元量子码
    $ n $$ \lambda $$ {g_1}(x) $$ {g_2}(x) $$ \phi (C) $$ {[[n,k,d]]_8} $$ {[[n',k',d']]_8} $
    $ 5 $$ 1 + v + v{\omega ^7} $$ 1{\omega ^{42}}1 $$ 1{\omega ^{56}}{\omega ^{28}} $$ {[10,6,5]_{64}} $$ {[[10,2,5]]_8} $MDS
    $ 7 $$ 1 + v + v{\omega ^{21}} $$ 1{\omega ^9} $$ 1{\omega ^3} $$ {[14,12,3]_{64}} $$ {[[14,10,3]]_8} $MDS
    $ 7 $$ 1 + v + v{\omega ^{21}} $$ 1{\omega ^9} $$ (1{\omega ^3})(1{\omega ^{12}}) $$ {[14,11,4]_{64}} $$ {[[14,8,4]]_8} $MDS
    $ 21 $$ 1 + v + v{\omega ^{21}} $$ 1{\omega ^3} $$ 1\omega $$ {[42,40,3]_{64}} $$ {[[42,38,3]]_8} $MDS
    $ 35 $$ 1 + v + v{\omega ^{21}} $$ (1{\omega ^9})(1{\omega ^{57}}{\omega ^9}) $$ 1{\omega ^6} $$ {[70,66,4]_{64}} $$ {[[70,62, \ge 4]]_8} $$ {[[70,46,3]]_8} $[17]
    $ 39 $$ 1 + v + v{\omega ^{21}} $$ (1{\omega ^{47}}{\omega ^{42}})(1{\omega ^{31}}{\omega ^{21}}) $$ (1{\omega ^{27}}{\omega ^{35}})(1{\omega ^{45}}{\omega ^{14}}) $$ {[78,70,5]_{64}} $$ {[[78,62, \ge 5]]_8} $$ {[[78,46,5]]_8} $[17]
    $ 49 $$ 1 + v + v{\omega ^7} $$ 1{\omega ^9} $$ (1{\omega ^{22}})(1{\omega ^{31}}) $$ {[98,95,3]_{64}} $$ {[[98,92, \ge 3]]_8} $$ {[[99,89,3]]_8} $[17]
    $ 63 $$ 1 $$ (1\omega )(1{\omega ^2}) $$ (1{\omega ^3})(1{\omega ^4}) $$ {[126,122,4]_{64}} $$ {[[126,118, \ge 4]]_8} $$ {[[127,113,3]]_8} $[17]
    $ 65 $$ 1 + v + v{\omega ^{21}} $$ (1{\omega ^4}1)(1{\omega ^8}1) $$ (1{\omega ^{52}}{\omega ^{21}})(1{\omega ^{19}}{\omega ^{21}}) $$ {[130,122,5]_{64}} $$ {[[130,114, \ge 5]]_8} $$ {[[133,113,5]]_8} $[17]
    $ 73 $$ 1 + v + v{\omega ^7} $$ 1{\omega ^{36}}01 $$ 10{\omega ^{50}}{\omega ^{21}} $$ {[146,140,4]_{64}} $$ {[[146,134, \ge 4]]_8} $$ {[[147,122,4]]_8} $[17]
    $ 91 $$ 1 + v + v{\omega ^7} $$ (1{\omega ^9})(1{\omega ^{31}}{\omega ^{36}}) $$ (1{\omega ^{52}})(1{\omega ^{44}}{\omega ^{50}})(1{\omega ^{61}}) $$ {[182,175,5]_{64}} $$ {[[182,168, \ge 5]]_8} $$ {[[183,143,4]]_8} $[17]
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    本文定义了一个从有限环$ R = {F_{{4^m}}} + v{F_{{4^m}}} $到有限域$ {F_{{4^m}}} $上的Gray映射,研究了环$ R $上厄米特对偶包含常循环码的条件,在此基础上提出了一种构造$ {2^m} $元量子码的新方法,并据此构造了有限域$ {F_4} $$ {F_8} $上的一些新量子码。通过不同有限环上的常循环码构造更多$ {2^m} $元新量子码是一个值得继续探索的问题。

  • [1]
    CALDERBANK A R, RAINS E M, SHOR P M, et al. Quantum error correction via codes over GF(4)[J]. IEEE Transactions on Information Theory, 1998, 44(4): 1369–1387. doi: 10.1109/18.681315
    [2]
    ASHIKHMIN A and KNILL E. Nonbinary quantum stabilizer codes[J]. IEEE Transactions on Information Theory, 2001, 47(7): 3065–3072. doi: 10.1109/18.959288
    [3]
    KAI Xiaoshan, ZHU Shixin, and LI Ping. Constacyclic codes and some new quantum MDS codes[J]. IEEE Transactions on Information Theory, 2014, 60(4): 2080–2086. doi: 10.1109/TIT.2014.2308180
    [4]
    CHEN Bocong, LING San, and ZHANG Guanghui. Application of constacyclic codes to quantum MDS codes[J]. IEEE Transactions on Information Theory, 2015, 61(3): 1474–1484. doi: 10.1109/TIT.2015.2388576
    [5]
    朱士信, 黄山, 李锦. 有限域上常循环厄密特对偶包含码及其应用[J]. 电子与信息学报, 2018, 40(5): 1072–1078. doi: 10.11999/JEIT170735

    ZHU Shixin, HUANG Shan, and LI Jin. Constacyclic Hermitian dual-containing codes over finite fields and their application[J]. Journal of Electronics &Information Technology, 2018, 40(5): 1072–1078. doi: 10.11999/JEIT170735
    [6]
    QIAN Jianfa, MA Wenping, and GUO Wangmei. Quantum codes from cyclic codes over finite ring[J]. International Journal of Quantum Information, 2009, 7(6): 1277–1283. doi: 10.1142/S0219749909005560
    [7]
    QIAN Jianfa. Quantum codes from cyclic codes over $ {F_2} + v{F_2} $ [J]. Journal of Information and Computational Science, 2013, 10(6): 1715–1722. doi: 10.12733/jics20101705
    [8]
    ASHRAF M and MOHAMMAD G. Construction of quantum codes from cyclic codes over $ {F_p} + v{F_p} $ [J]. International Journal of Information and Coding Theory, 2015, 3(2): 137–144. doi: 10.1504/IJICOT.2015.072627
    [9]
    GAO Jian and WANG Yongkang. $ u $ -Constacyclic codes over $ F_{P}+u F_{p} $ and their applications of constructing new non-binary quantum codes[J]. Quantum Information Processing, 2018, 17(1): 4. doi: 10.1007/s11128-017-1775-8
    [10]
    ALAHMADI A, ISLAM H, PRAKASH O, et al. New quantum codes from constacyclic codes over a non-chain ring[J]. Quantum Information Processing, 2021, 20(2): 60. doi: 10.1007/s11128-020-02977-y
    [11]
    ISLAM H, PRAKASH O, and VERMA R K. New quantum codes from constacyclic codes over the ring $ {R_{k, m}} $ [J]. Advances in Mathematics of Communications, 2022, 16(1): 17–35. doi: 10.3934/amc.2020097
    [12]
    WANG Yu, KAI Xiaoshan, SUN Zhonghua, et al. Quantum codes from Hermitian dual-containing constacyclic codes over $ \mathbb{F}_{q^{2}}+v \mathbb{F}_{q^{2}} $ [J]. Quantum Information Processing, 2021, 20(3): 122. doi: 10.1007/s11128-021-03052-w
    [13]
    SHI Xiaoping, HUANG Xinmei, and YUE Qin. Construction of new quantum codes derived from constacyclic codes over $ F_{q^{2}}+u F_{q^{2}}+\cdots+u^{r-1} F_{q^{2}} $ [J]. Applicable Algebra in Engineering, Communication and Computing, 2021, 32(5): 603–620. doi: 10.1007/s00200-020-00415-1
    [14]
    ISLAM H, PATEL S, PRAKASH O, et al. A family of constacyclic codes over a class of non-chain rings $ {A_{q, r}} $ and new quantum codes[J]. Journal of Applied Mathematics and Computing, 2022, 68(4): 2493–2514. doi: 10.1007/s12190-021-01623-9
    [15]
    TANG Yongsheng, YAO Ting, SUN Zhonghua, et al. Nonbinary quantum codes from constacyclic codes over polynomial residue rings[J]. Quantum Information Processing, 2020, 19(3): 84. doi: 10.1007/s11128-020-2584-z
    [16]
    LIU Yan, SHI Minjia, SEPASDAR Z, et al. Construction of Hermitian self-dual constacyclic codes over $ {F_{{q^2}}} + v{F_{{q^2}}} $ [J]. Applied and Computational Mathematics, 2016, 15(3): 359–369.
    [17]
    EDEL Y. Some good quantum twisted codes[EB/OL]. https://www.mathi.uni-heidelberg.de/~yves/Matritzen/QTBCH/QTBCHIndex.html, 2022.
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