02 2022 档案

Extreme expected values and their applications in quantum metrology
摘要：DOI: 10.1103/PhysRevA.105.023718 Eq.(48): \[ \left< \left( n_a-n_b \right) ^2 \right> -\left< \left( n_a-n_b \right) \right> ^2 \\ c\left( |\phi 0\ran 阅读全文
posted @ 2022-02-27 18:16 narip 阅读(25) 评论(0) 推荐(0)
Optimal Quantum-Enhanced Interferometry Using a Laser Power Source
摘要：DOI: 10.1103/PhysRevLett.111.173601 Eq(17): \[ a_2=\frac{x+ip}{\sqrt{2}} \\ 2\bar{N}+1=2\left< {a_2}^{\dagger}a_2 \right> +1=2\left< \frac{x-ip}{\sqrt 阅读全文
posted @ 2022-02-27 13:36 narip 阅读(31) 评论(0) 推荐(0)
Quantum Metrology
摘要：State after Beam Splitter Refer to page 9 of [^1] $$ |1\rangle |0\rangle \ \left( \begin{matrix} \cos \frac{\phi}{2}& -\sin \frac{\phi}{2}\ \sin \frac 阅读全文
posted @ 2022-02-25 22:13 narip 阅读(24) 评论(0) 推荐(0)
Useful sentences
摘要：In quantum mechanics, the electric fields are operators as explained by second quantization and Fock states. Each electrical field operator can furthe 阅读全文
posted @ 2022-02-25 20:59 narip 阅读(33) 评论(0) 推荐(0)
Matrix Analysis
摘要：Norm Norm for vectors \[ \begin{aligned} &\|x\| \geq 0 \\ &\|x\|=0 \text { if and only if } x=0 \\ &\|c x\|=|c|\|x\| \\ &\|x+y\| \leq\|x\|+\|y\| \end{ 阅读全文
posted @ 2022-02-24 21:48 narip 阅读(42) 评论(0) 推荐(0)
Spacelike, timelike and lightlike
摘要：Quoted from StackExchange. Suppose we have two events \((x_1,y_1,z_1,t_1)\) and \((x_2,y_2,z_2,t_2)\). Then we can define \(\Delta s^2 = -(c\Delta t)^ 阅读全文
posted @ 2022-02-24 19:36 narip 阅读(86) 评论(0) 推荐(0)
Does large quantum Fisher information imply Bell correlations?
摘要：DOI: 10.1103/PhysRevA.99.040101 Eq(8): Try to use Lagerange's multipliers method, only find it too complicated: \[ \begin{cases} \sum_{n=1}{\frac{p_nn 阅读全文
posted @ 2022-02-23 20:18 narip 阅读(30) 评论(0) 推荐(0)