量子多体态的神经网络表示(一)
量子多体态的神经网络表示
这是一大堆公式来袭!!!!
神经网络量子态
设 Q 1 , Q 2 , … , Q N Q_{1}, Q_{2}, \ldots, Q_{N} Q1,Q2,…,QN是具有尺寸为 d 1 , d 2 , … , d N d_{1}, d_{2}, \ldots, d_{N} d1,d2,…,dN 的状态空间 H 1 , H 2 , … , H N H_{1}, H_{2}, \ldots, H_{N} H1,H2,…,HN 的 N N N 个量子系统。考虑Q1,Q2,…,QN的复合系统 Q 的状态空间为 H = H 1 ⊗ H 2 ⊗ … ⊗ H N \mathcal{H}=\mathcal{H}_{1} \otimes \mathcal{H}_{2} \otimes \ldots \otimes \mathcal{H}_{N} H=H1⊗H2⊗…⊗HN。设 S 1 , S 2 , … , S N S_{1}, S_{2}, \ldots, S_{N} S1,S2,…,SN分别是系统 Q 1 , Q 2 , … , Q N Q_{1}, Q_{2}, \ldots, Q_{N} Q1,Q2,…,QN的非简并观测量,那么 S = S 1 ⊗ S 2 ⊗ … ⊗ S N \mathcal{S}=\mathcal{S}_{1} \otimes \mathcal{S}_{2} \otimes \ldots \otimes \mathcal{S}_{N} S=S1⊗S2⊗…⊗SN是复合系统 Q Q Q 的可观测值,于是
S j ∣ ψ k j ⟩ = λ k j ∣ ψ k j ⟩ ( k j = 0 , 1 , … , d j − 1 ) S_{j}\left|\psi_{k_{j}}\right\rangle=\lambda_{k_{j}}\left|\psi_{k_{j}}\right\rangle\left(k_{j}=0,1, \ldots, d_{j}-1\right) Sj∣∣ψkj⟩=λkj∣∣ψkj⟩(kj=0,1,…,dj−1)
很容易知道 S = S 1 ⊗ S 2 ⊗ … ⊗ S N S=S_{1} \otimes S_{2} \otimes \ldots \otimes S_{N} S=S1⊗S2⊗…⊗SN对应的特征值 λ k 1 λ k 2 … λ k N \lambda_{k_{1}} \lambda_{k_{2}} \ldots \lambda_{k_{N}} λk1λk2…λkN和本征基 ∣ ψ k 1 ⟩ ⊗ ∣ ψ k 2 ⟩ ⊗ … ⊗ ∣ ψ k N ⟩ ( k j = 0 , 1 , … , d j − 1 ) \left|\psi_{k_{1}}\right\rangle \otimes\left|\psi_{k_{2}}\right\rangle \otimes \ldots \otimes\left|\psi_{k_{N}}\right\rangle\left(k_{j}=0,1, \ldots, d_{j}-1\right) ∣ψk1⟩⊗∣ψk2⟩⊗…⊗∣ψkN⟩(kj=0,1,…,dj−1)
令输入空间为;
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V(S)=\left\{\Lambda_{k_{1} k_{2} \ldots k_{N}} \equiv\left(\lambda_{k_{1}}, \lambda_{k_{2}}, \ldots, \lambda_{k_{N}}\right)^{\mathrm{T}}: k_{j}=0,1, \ldots, d_{j}-1\right\}
V(S)={Λk1k2…kN≡(λk1,λk2,…,λkN)T:kj=0,1,…,dj−1}
其中参数
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a=\left(a_{1}, a_{2}, \ldots, a_{N}\right)^{\mathrm{T}} \in \mathbb{C}^{N}
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\Omega=(a, b, W)
Ω=(a,b,W),于是可以获得神经网络量子波函数neural network quantum wave function(NNQWF):
Ψ S , Ω ( λ k 1 , λ k 2 , … , λ k N ) = ∑ h i = ± 1 exp ( ∑ j = 1 N a j λ k j + ∑ i = 1 M b i h i + ∑ i = 1 M ∑ j = 1 N W i j h i λ k j ) \begin{array}{l} \Psi_{S, \Omega}\left(\lambda_{k_{1}}, \lambda_{k_{2}}, \ldots, \lambda_{k_{N}}\right) \\ =\sum_{h_{i}=\pm 1} \exp \left(\sum_{j=1}^{N} a_{j} \lambda_{k_{j}}+\sum_{i=1}^{M} b_{i} h_{i}+\sum_{i=1}^{M} \sum_{j=1}^{N} W_{i j} h_{i} \lambda_{k_{j}}\right) \end{array} ΨS,Ω(λk1,λk2,…,λkN)=∑hi=±1exp(∑j=1Najλkj+∑i=1Mbihi+∑i=1M∑j=1NWijhiλkj)
对于一些
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\Psi_{S, \Omega}\left(\lambda_{k_{1}}, \lambda_{k_{2}}, \ldots, \lambda_{k_{N}}\right) \neq 0
ΨS,Ω(λk1,λk2,…,λkN)=0,定义:
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\begin{aligned} \left|\Psi_{S, \Omega}\right\rangle=& \sum_{\Lambda_{k_{1} k_{2} \ldots k_{N}} \in V(S)} \Psi_{S, \Omega}\left(\lambda_{k_{1}}, \lambda_{k_{2}}, \ldots, \lambda_{k_{N}}\right) \cdot\left|\psi_{k_{1}}\right\rangle \otimes\left|\psi_{k_{2}}\right\rangle \otimes \ldots \otimes\left|\psi_{k_{N}}\right\rangle \end{aligned}
∣ΨS,Ω⟩=Λk1k2…kN∈V(S)∑ΨS,Ω(λk1,λk2,…,λkN)⋅∣ψk1⟩⊗∣ψk2⟩⊗…⊗∣ψkN⟩
它是希尔伯特空间H的非零向量(不一定归一化)。我们称其为由参数
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Ω=(a,b,W) 和输入可观察到的
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S_{1}, S_{2}, \ldots, S_{N}
S1,S2,…,SN 引起的神经网络量子态(NNQS):
对NNQS进行编码的人工神经网络,具有一组N个可见的人工神经元(蓝色磁盘)和一组M个隐藏的神经元(黄色磁盘), 对于输入的可观察到的S的每个值
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Λk1k2…kN,神经网络计算
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\Psi_{S, \Omega}\left(\lambda_{k_{1}}, \lambda_{k_{2}}, \ldots, \lambda_{k_{N}}\right)
ΨS,Ω(λk1,λk2,…,λkN)的值。
使用内积符号,可以写成:
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\begin{array}{l} \sum_{j=1}^{N} a_{j} \lambda_{k_{j}}+\sum_{i=1}^{M} b_{i} h_{i}+\sum_{i=1}^{M} \sum_{j=1}^{N} W_{i j} h_{i} \lambda_{k_{j}} \\ =\left\langle\Lambda_{k_{1} k_{2} \ldots k_{N}}, a\right\rangle+\left\langle h, b+W \Lambda_{k_{1} k_{2} \ldots k_{N}}\right\rangle \end{array}
∑j=1Najλkj+∑i=1Mbihi+∑i=1M∑j=1NWijhiλkj=⟨Λk1k2…kN,a⟩+⟨h,b+WΛk1k2…kN⟩
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\Psi_{S, \Omega}\left(\lambda_{k_{1}}, \lambda_{k_{2}}, \ldots, \lambda_{k_{N}}\right)=\mathrm{e}^{\left\langle\Lambda_{k_{1} k_{2}, k_{N}}, a\right\rangle} \cdot \sum_{h_{i}=\pm 1} \mathrm{e}^{\left\langle h, b+W \Lambda_{k_{1}} k_{2} \ldots k_{N}\right\rangle}
ΨS,Ω(λk1,λk2,…,λkN)=e⟨Λk1k2,kN,a⟩⋅∑hi=±1e⟨h,b+WΛk1k2…kN⟩
NNQWF的另外一种形式
已知
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\mathrm{e}^{\left\langle\Lambda_{k_{1} k_{2} \ldots k_{N}}, a\right\rangle}=\mathrm{e}^{\sum_{j=1}^{N} a_{j} \lambda_{k_{j}}}=\prod_{j=1}^{N} \mathrm{e}^{a_{j} \lambda_{k_{j}}}
e⟨Λk1k2…kN,a⟩=e∑j=1Najλkj=∏j=1Neajλkj
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xi=bi+∑j=1NWijλkj
∑ h i = ± 1 e ⟨ h , b + W Λ k 1 k 2 … k N ⟩ = ∑ h i = ± 1 e ∑ i = 1 M h i [ b i + ∑ j = 1 N W i j λ k j ] = ∑ h i = ± 1 ∏ i = 1 M e x i h i = ∑ h 1 = ± 1 … ∑ h M = ± 1 e x 1 h 1 e x 2 h 2 ⋯ e x M h M = ( e x 1 + e − x 1 ) ( e x 2 + e − x 2 ) ⋯ ( e x M + e − x M ) = ∏ i = 1 M 2 cosh ( x i ) \begin{array}{l} \sum_{h_{i}=\pm 1} \mathrm{e}^{\left\langle h, b+W \Lambda_{k_{1} k_{2} \ldots k_{N}}\right\rangle} \\ =\sum_{h_{i}=\pm 1} \mathrm{e}^{\sum_{i=1}^{M} h_{i}\left[b_{i}+\sum_{j=1}^{N} W_{i j} \lambda_{k_{j}}\right]} \\ =\sum_{h_{i}=\pm 1} \prod_{i=1}^{M} \mathrm{e}^{x_{i} h_{i}} \\ =\sum_{h_{1}=\pm 1} \ldots \sum_{h_{M}=\pm 1} \mathrm{e}^{x_{1} h_{1}} \mathrm{e}^{x_{2} h_{2}} \cdots \mathrm{e}^{x_{M} h_{M}} \\ =\left(\mathrm{e}^{x_{1}}+\mathrm{e}^{-x_{1}}\right)\left(\mathrm{e}^{x_{2}}+\mathrm{e}^{-x_{2}}\right) \cdots\left(\mathrm{e}^{x_{M}}+\mathrm{e}^{-x_{M}}\right) \\ =\prod_{i=1}^{M} 2 \cosh \left(x_{i}\right) \end{array} ∑hi=±1e⟨h,b+WΛk1k2…kN⟩=∑hi=±1e∑i=1Mhi[bi+∑j=1NWijλkj]=∑hi=±1∏i=1Mexihi=∑h1=±1…∑hM=±1ex1h1ex2h2⋯exMhM=(ex1+e−x1)(ex2+e−x2)⋯(exM+e−xM)=∏i=1M2cosh(xi)
注释: cosh x = e x + e − x 2 = e 2 x + 1 2 e x = 1 + e − 2 x 2 e − x \cosh x=\frac{e^{x}+e^{-x}}{2}=\frac{e^{2 x}+1}{2 e^{x}}=\frac{1+e^{-2 x}}{2 e^{-x}} coshx=2ex+e−x=2exe2x+1=2e−x1+e−2x
于是:
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\begin{array}{l} \Psi_{S, \Omega}\left(\lambda_{k_{1}}, \lambda_{k_{2}}, \ldots, \lambda_{k_{N}}\right) \\ =\prod_{j=1}^{N} \mathrm{e}^{a_{j} \lambda_{k_{j}}} \cdot \prod_{i=1}^{M} 2 \cosh \left(b_{i}+\sum_{j=1}^{N} W_{i j} \lambda_{k_{j}}\right) . \end{array}
ΨS,Ω(λk1,λk2,…,λkN)=∏j=1Neajλkj⋅∏i=1M2cosh(bi+∑j=1NWijλkj).
我们将此网络称为量子人工神经网络,因为它的输入是量子可观察量的特征值,结果是NNQWF的值,而它的网络结构类似于通常的人工神经网络:
NNQS的张量积
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a \in \mathbb{C}^{N}, b \in \mathbb{C}^{N}, W \in \mathbb{C}^{N \times N}
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b^{\prime \prime}=\left(\begin{array}{c} \frac{\pi \mathrm{i}}{3} \\ \frac{\pi \mathrm{i}}{3} \\ \vdots \\ \frac{\pi \mathrm{i}}{3} \end{array}\right) \in \mathbb{C}^{M-N}
b′′=⎝⎜⎜⎜⎛3πi3πi⋮3πi⎠⎟⎟⎟⎞∈CM−N
b ′ = ( b b ′ ′ ) ∈ C M b^{\prime}=\left(\begin{array}{c} b \\ b^{\prime \prime} \end{array}\right) \in \mathbb{C}^{M} b′=(bb′′)∈CM
W ′ = ( W 0 ) = [ W i j ′ ] ∈ C M × N W^{\prime}=\left(\begin{array}{c} W \\ 0 \end{array}\right)=\left[W_{i j}^{\prime}\right] \in \mathbb{C}^{M \times N} W′=(W0)=[Wij′]∈CM×N
定义一个新的参数: Ω ′ = ( a , b ′ , W ′ ) \Omega^{\prime}=\left(a, b^{\prime}, W^{\prime}\right) Ω′=(a,b′,W′)
b i ′ = b i ( i = 1 , 2 , … , N ) , b i ′ = π i 3 ( i = N + 1 , N + 2 , … , M ) W i j ′ = W i j ( 1 ≤ i ≤ N , 1 ≤ j ≤ N ) W i j ′ = 0 ( i = N + 1 , N + 2 , … , M , j = 1 , 2 , … , N ) \begin{array}{l} b_{i}^{\prime}=b_{i}(i=1,2, \ldots, N),\\ b_{i}^{\prime}=\frac{\pi \mathrm{i}}{3}(i=N+1, N+2, \ldots, M) \\ W_{i j}^{\prime}=W_{i j}(1 \leq i \leq N, 1 \leq j \leq N) \\ W_{i j}^{\prime}=0(i=N+1, N+2, \ldots, M, j=1,2, \ldots, N) \end{array} bi′=bi(i=1,2,…,N),bi′=3πi(i=N+1,N+2,…,M)Wij′=Wij(1≤i≤N,1≤j≤N)Wij′=0(i=N+1,N+2,…,M,j=1,2,…,N)
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2cosh(bi′+j=1∑NWij′λkj)=2cosh3πi=2cos3π=1
所以
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\prod_{i=1}^{M} 2 \cosh \left(b_{i}^{\prime}+\sum_{j=1}^{N} W_{i j}^{\prime} \lambda_{k_{j}}\right)=\prod_{i=1}^{N} 2 \cosh \left(b_{i}+\sum_{j=1}^{N} W_{i j} \lambda_{k_{j}}\right)
i=1∏M2cosh(bi′+j=1∑NWij′λkj)=i=1∏N2cosh(bi+j=1∑NWijλkj)
Ψ S , Ω ′ ( λ k 1 , λ k 2 , … , λ k N ) = Ψ S , Ω ( λ k 1 , λ k 2 , … , λ k N ) , ∀ Λ k 1 k 2 … k N \Psi_{S, \Omega^{\prime}}\left(\lambda_{k_{1}}, \lambda_{k_{2}}, \ldots, \lambda_{k_{N}}\right)=\Psi_{S, \Omega}\left(\lambda_{k_{1}}, \lambda_{k_{2}}, \ldots, \lambda_{k_{N}}\right), \quad \forall \Lambda_{k_{1} k_{2} \ldots k_{N}} ΨS,Ω′(λk1,λk2,…,λkN)=ΨS,Ω(λk1,λk2,…,λkN),∀Λk1k2…kN
同理
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\begin{array}{l} S^{\prime}=S_{1}^{\prime} \otimes \ldots \otimes S_{N^{\prime}}^{\prime}, S^{\prime \prime}=S_{1}^{\prime \prime} \otimes \ldots \otimes S_{N^{\prime \prime}}^{\prime \prime} \\ \Omega^{\prime}=\left(a^{\prime}, b^{\prime}, W^{\prime}\right), \Omega^{\prime \prime}=\left(a^{\prime \prime}, b^{\prime \prime}, W^{\prime \prime}\right) \end{array}
S′=S1′⊗…⊗SN′′,S′′=S1′′⊗…⊗SN′′′′Ω′=(a′,b′,W′),Ω′′=(a′′,b′′,W′′)
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\begin{array}{l} S=S^{\prime} \otimes S^{\prime \prime}, N=N^{\prime}+N^{\prime \prime}, M=M^{\prime}+M^{\prime \prime} \\ a=\left(\begin{array}{c} a^{\prime} \\ a^{\prime \prime} \end{array}\right), b=\left(\begin{array}{c} b^{\prime} \\ b^{\prime \prime} \end{array}\right), \\ W=\left[W_{i j}\right]=\left(\begin{array}{cc} W_{M^{\prime} \times N^{\prime}}^{\prime} & 0 \\ 0 & W_{M^{\prime \prime} \times N^{\prime \prime}}^{\prime \prime} \end{array}\right), \Omega=(a, b, W) \end{array}
S=S′⊗S′′,N=N′+N′′,M=M′+M′′a=(a′a′′),b=(b′b′′),W=[Wij]=(WM′×N′′00WM′′×N′′′′),Ω=(a,b,W)
∣ Ψ S ′ , Ω ′ ′ ⟩ = ∑ ( λ k 1 , λ k 2 , … , λ k N ′ ) T ∈ V ( S ′ ) Ψ S ′ , Ω ′ ′ ( λ k 1 , λ k 2 , … , λ k N ′ ) ⋅ ∣ ψ k 1 ⟩ ⊗ ∣ ψ k 2 ⟩ ⊗ … ⊗ ∣ ψ k N ′ ⟩ \begin{aligned} \left|\Psi_{S^{\prime}, \Omega^{\prime}}^{\prime}\right\rangle=& \sum_{\left(\lambda_{k_{1}}, \lambda_{k_{2}}, \ldots, \lambda_{k_{N^{\prime}}}\right)^{\mathrm{T}} \in V\left(S^{\prime}\right)} \Psi_{S^{\prime}, \Omega^{\prime}}^{\prime}\left(\lambda_{k_{1}}, \lambda_{k_{2}}, \ldots, \lambda_{k_{N^{\prime}}}\right) \cdot\left|\psi_{k_{1}}\right\rangle \otimes\left|\psi_{k_{2}}\right\rangle \otimes \ldots \otimes\left|\psi_{k_{N^{\prime}}}\right\rangle \end{aligned} ∣∣ΨS′,Ω′′⟩=(λk1,λk2,…,λkN′)T∈V(S′)∑ΨS′,Ω′′(λk1,λk2,…,λkN′)⋅∣ψk1⟩⊗∣ψk2⟩⊗…⊗∣∣ψkN′⟩
∣ Ψ S ′ ′ , Ω ′ ′ ′ ′ ⟩ = ∑ ( μ m 1 , μ m 2 , … , μ m N ′ ′ ) T ∈ V ( S ′ ′ ) Ψ S ′ ′ , Ω ′ ′ ′ ′ ( μ m 1 , μ m 2 , … , μ m N ′ ′ ) ⋅ ∣ ϕ m 1 ⟩ ⊗ ∣ ϕ m 2 ⟩ ⊗ … ⊗ ∣ ϕ m N ′ ′ ⟩ \begin{aligned} \left|\Psi_{S^{\prime \prime}, \Omega^{\prime \prime}}^{\prime \prime}\right\rangle=& \sum_{\left(\mu_{m_{1}}, \mu_{m_{2}}, \ldots, \mu_{m_{N^{\prime \prime}}}\right)^{\mathrm{T}} \in V\left(S^{\prime \prime}\right)} \Psi_{S^{\prime \prime}, \Omega^{\prime \prime}}^{\prime \prime}\left(\mu_{m_{1}}, \mu_{m_{2}}, \ldots, \mu_{m_{N^{\prime \prime}}}\right)\cdot\left|\phi_{m_{1}}\right\rangle \otimes\left|\phi_{m_{2}}\right\rangle \otimes \ldots \otimes\left|\phi_{m_{N^{\prime \prime}}}\right\rangle \end{aligned} ∣∣ΨS′′,Ω′′′′⟩=(μm1,μm2,…,μmN′′)T∈V(S′′)∑ΨS′′,Ω′′′′(μm1,μm2,…,μmN′′)⋅∣ϕm1⟩⊗∣ϕm2⟩⊗…⊗∣∣ϕmN′′⟩
Ψ S ′ , Ω ′ ′ ( λ k 1 , λ k 2 , … , λ k N ′ ) ⋅ Ψ S ′ ′ , Ω ′ ′ ′ ′ ( μ m 1 , μ m 2 , … , μ m N ′ ′ ) \Psi_{S^{\prime}, \Omega^{\prime}}^{\prime}\left(\lambda_{k_{1}}, \lambda_{k_{2}}, \ldots, \lambda_{k_{N^{\prime}}}\right) \cdot \Psi_{S^{\prime \prime}, \Omega^{\prime \prime}}^{\prime \prime}\left(\mu_{m_{1}}, \mu_{m_{2}}, \ldots, \mu_{m_{N^{\prime \prime}}}\right) ΨS′,Ω′′(λk1,λk2,…,λkN′)⋅ΨS′′,Ω′′′′(μm1,μm2,…,μmN′′)
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\begin{aligned} =&\left(\prod_{j=1}^{N^{\prime}} \mathrm{e}^{a_{j}^{\prime} \lambda_{k_{j}}}\right) \cdot\left(\prod_{j=1}^{N^{\prime \prime}} \mathrm{e}^{a_{j}^{\prime \prime} \mu_{m_{j}}}\right) \cdot\left(\prod_{i=1}^{M^{\prime}} 2 \cosh \left(b_{i}^{\prime}+\sum_{j=1}^{N^{\prime}} W_{i j}^{\prime} \lambda_{k_{j}}\right)\right) \\ & \cdot\left(\prod_{i=1}^{M^{\prime \prime}} 2 \cosh \left(b_{i}^{\prime \prime}+\sum_{j=1}^{N^{\prime \prime}} W_{i j}^{\prime \prime} \mu_{m_{j}}\right)\right) \\ =&\left(\prod_{j=1}^{N} \mathrm{e}^{a_{j} \xi_{j_{j}}}\right) \cdot\left(\prod_{i=1}^{M} 2 \cosh \left(b_{i}+\sum_{j=1}^{N} W_{i j} \xi_{j}\right)\right) \\ =& \Psi_{S, \Omega}\left(\xi_{l_{1}}, \xi_{l_{2}}, \ldots, \xi_{l_{N}}\right) \end{aligned}
===⎝⎛j=1∏N′eaj′λkj⎠⎞⋅⎝⎛j=1∏N′′eaj′′μmj⎠⎞⋅⎝⎛i=1∏M′2cosh⎝⎛bi′+j=1∑N′Wij′λkj⎠⎞⎠⎞⋅⎝⎛i=1∏M′′2cosh⎝⎛bi′′+j=1∑N′′Wij′′μmj⎠⎞⎠⎞(j=1∏Neajξjj)⋅(i=1∏M2cosh(bi+j=1∑NWijξj))ΨS,Ω(ξl1,ξl2,…,ξlN)
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\left(\xi_{l_{1}}, \xi_{l_{2}}, \ldots, \xi_{l_{N}}\right)=\left(\lambda_{k_{1}}, \lambda_{k_{2}}, \ldots, \lambda_{k_{N^{\prime}}}, \mu_{m_{1}}, \mu_{m_{2}}, \ldots, \mu_{m_{N^{\prime \prime}}}\right)
(ξl1,ξl2,…,ξlN)=(λk1,λk2,…,λkN′,μm1,μm2,…,μmN′′)
∣ Ψ S ′ , Ω ′ ′ ⟩ ⊗ ∣ Ψ S ′ ′ , Ω ′ ′ ′ ′ ⟩ = ∑ ( λ 1 , λ k 2 , … , λ N ′ ) T ∈ V ( S ′ ) ( μ m 1 , μ m 2 , … , μ m N ′ ′ ) T ∈ V ( S ′ ′ ) Ψ S ′ , Ω ′ ′ ( λ k 1 , λ k 2 , … , λ k N ′ ) ⋅ Ψ S ′ ′ , Ω ′ ′ ′ ′ ( μ m 1 , μ m 2 , … , μ m N ′ ′ ) ⋅ ∣ ψ k 1 ⟩ ⊗ ∣ ψ k 2 ⟩ ⊗ … ⊗ ∣ ψ k N ′ ⟩ ⊗ ∣ ϕ m 1 ⟩ ⊗ ∣ ϕ m 2 ⟩ ⊗ … ⊗ ∣ ϕ m N ′ ′ ⟩ = ∑ ( ξ l , ξ l 2 , … , ξ l N ) T ∈ V ( S ) Ψ S , Ω ( ξ l 1 , ξ l 2 , … , ξ l N ) ∣ φ l 1 ⟩ ⊗ … ⊗ ∣ φ l N ⟩ = ∣ Φ S , Ω ⟩ \begin{array}{l} \left|\Psi_{S^{\prime}, \Omega^{\prime}}^{\prime}\right\rangle \otimes\left|\Psi_{S^{\prime \prime}, \Omega^{\prime \prime}}^{\prime \prime}\right\rangle \\ =\sum_{\left(\lambda_{1}, \lambda_{k_{2}}, \ldots, \lambda_{N^{\prime}}\right)^{\mathrm{T}} \in V\left(S^{\prime}\right)\left(\mu_{m_{1}}, \mu_{m_{2}}, \ldots, \mu_{m_{N^{\prime \prime}}}\right)^{\mathrm{T}} \in V\left(S^{\prime \prime}\right)} \\ \Psi_{S^{\prime}, \Omega^{\prime}}^{\prime}\left(\lambda_{k_{1}}, \lambda_{k_{2}}, \ldots, \lambda_{k_{N^{\prime}}}\right) \cdot \Psi_{S^{\prime \prime}, \Omega^{\prime \prime}}^{\prime \prime}\left(\mu_{m_{1}}, \mu_{m_{2}}, \ldots, \mu_{m_{N^{\prime \prime}}}\right) \\ \quad \cdot\left|\psi_{k_{1}}\right\rangle \otimes\left|\psi_{k_{2}}\right\rangle \otimes \ldots \otimes\left|\psi_{k_{N^{\prime}}}\right\rangle \otimes\left|\phi_{m_{1}}\right\rangle \otimes\left|\phi_{m_{2}}\right\rangle \otimes \ldots \otimes\left|\phi_{m_{N^{\prime \prime}}}\right\rangle \\ =\quad \sum_{\left(\xi_{l}, \xi_{l_{2}}, \ldots, \xi_{l_{N}}\right)^{\mathrm{T}} \in V(S)} \Psi_{S, \Omega}\left(\xi_{l_{1}}, \xi_{l_{2}}, \ldots, \xi_{l_{N}}\right)\left|\varphi_{l_{1}}\right\rangle \otimes \ldots \otimes\left|\varphi_{l_{N}}\right\rangle \\ =\left|\Phi_{S, \Omega}\right\rangle \end{array} ∣∣ΨS′,Ω′′⟩⊗∣∣ΨS′′,Ω′′′′⟩=∑(λ1,λk2,…,λN′)T∈V(S′)(μm1,μm2,…,μmN′′)T∈V(S′′)ΨS′,Ω′′(λk1,λk2,…,λkN′)⋅ΨS′′,Ω′′′′(μm1,μm2,…,μmN′′)⋅∣ψk1⟩⊗∣ψk2⟩⊗…⊗∣∣ψkN′⟩⊗∣ϕm1⟩⊗∣ϕm2⟩⊗…⊗∣∣ϕmN′′⟩=∑(ξl,ξl2,…,ξlN)T∈V(S)ΨS,Ω(ξl1,ξl2,…,ξlN)∣φl1⟩⊗…⊗∣φlN⟩=∣ΦS,Ω⟩
这表明两个NNQS的张量积也是NNQS
局部统一运算(LUO)对NNQS的影响
有前面的内容我们知道
∣ Ψ S , Ω ⟩ = ∑ Λ k 1 , u N ∈ V ( S ) Ψ S , Ω ( λ k 1 , … , λ k N ) ∣ ψ k 1 ⟩ ⊗ … ⊗ ∣ ψ k N ⟩ \left|\Psi_{S, \Omega}\right\rangle=\sum_{\Lambda_{k_{1}, u_{N}} \in V(S)} \Psi_{S, \Omega}\left(\lambda_{k_{1}}, \ldots, \lambda_{k_{N}}\right)\left|\psi_{k_{1}}\right\rangle \otimes \ldots \otimes\left|\psi_{k_{N}}\right\rangle ∣ΨS,Ω⟩=Λk1,uN∈V(S)∑ΨS,Ω(λk1,…,λkN)∣ψk1⟩⊗…⊗∣ψkN⟩
令 U = U 1 ⊗ … ⊗ U N U=U_{1} \otimes \ldots \otimes U_{N} U=U1⊗…⊗UN,因为 U i S i U i † ∣ ϕ k i ⟩ = U i S i ∣ ψ k i ⟩ = U i ( λ k i ∣ ψ k i ⟩ ) = λ k i ∣ ϕ k i ⟩ U_{i} S_{i} U_{i}^{\dagger}\left|\phi_{k_{i}}\right\rangle=U_{i} S_{i}\left|\psi_{k_{i}}\right\rangle=U_{i}\left(\lambda_{k_{i}}\left|\psi_{k_{i}}\right\rangle\right)=\lambda_{k_{i}}\left|\phi_{k_{i}}\right\rangle UiSiUi†∣ϕki⟩=UiSi∣ψki⟩=Ui(λki∣ψki⟩)=λki∣ϕki⟩
于是
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\begin{array}{l} U\left|\Psi_{S, \Omega}\right\rangle \\ =\sum_{\Lambda_{k_{1}, k_{N}} \in V(S)} \Psi_{S, \Omega}\left(\lambda_{k_{1}}, \ldots, \lambda_{k_{N}}\right)\left|U_{1} \psi_{k_{1}}\right\rangle \otimes \ldots \otimes\left|U_{N} \psi_{k_{N}}\right\rangle \\ =\sum_{\Lambda_{k_{1} \ldots k_{N}} \in V\left(U S U^{\dagger}\right)} \Psi_{U S U^{\dagger}, \Omega}\left(\lambda_{k_{1}}, \ldots, \lambda_{k_{N}}\right)\left|\phi_{k_{1}}\right\rangle \otimes \ldots \otimes\left|\phi_{k_{N}}\right\rangle \\ =\left|\Psi_{U S U^{\dagger}, \Omega}\right\rangle \end{array}
U∣ΨS,Ω⟩=∑Λk1,kN∈V(S)ΨS,Ω(λk1,…,λkN)∣U1ψk1⟩⊗…⊗∣UNψkN⟩=∑Λk1…kN∈V(USU†)ΨUSU†,Ω(λk1,…,λkN)∣ϕk1⟩⊗…⊗∣ϕkN⟩=∣∣ΨUSU†,Ω⟩
这表明结果状态 U ∣ Ψ S , Ω ⟩ U\left|\Psi_{S, \Omega}\right\rangle U∣ΨS,Ω⟩也是具有输入可观察到的 U S U † U S U^{\dagger} USU†和参数 Ω Ω Ω的NNQS,并且与 U ∣ Ψ S , Ω ⟩ U\left|\Psi_{S, \Omega}\right\rangle U∣ΨS,Ω⟩具有相同的NNQWF。
当 S = σ 1 z ⊗ σ 2 z ⊗ … ⊗ σ N z S=\sigma_{1}^{z} \otimes \sigma_{2}^{z} \otimes \ldots \otimes \sigma_{N}^{z} S=σ1z⊗σ2z⊗…⊗σNz
∣ Ψ S , Ω ⟩ = ∑ Λ k 1 k 2 , k N ∈ { − 1 , 1 } N ( ∏ i = 1 M 2 Λ i ) ∣ ψ k 1 ⟩ ⊗ ∣ ψ k 2 ⟩ ⊗ … ⊗ ∣ ψ k N ⟩ \left|\Psi_{S, \Omega}\right\rangle=\sum_{\Lambda_{k_{1}} k_{2}, k_{N} \in\{-1,1\}^{N}}\left(\prod_{i=1}^{M} 2 \Lambda_{i}\right)\left|\psi_{k_{1}}\right\rangle \otimes\left|\psi_{k_{2}}\right\rangle \otimes \ldots \otimes\left|\psi_{k_{N}}\right\rangle ∣ΨS,Ω⟩=Λk1k2,kN∈{−1,1}N∑(i=1∏M2Λi)∣ψk1⟩⊗∣ψk2⟩⊗…⊗∣ψkN⟩
其中 Λ i = cos ( b + ω 1 λ k i − 1 + ω 0 λ k i + ω − 1 λ k i + 1 ) \Lambda_{i}=\cos \left(b+\omega_{1} \lambda_{k_{i-1}}+\omega_{0} \lambda_{k_{i}}+\omega_{-1} \lambda_{k_{i+1}}\right) Λi=cos(b+ω1λki−1+ω0λki+ω−1λki+1)