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2 votes
0 answers
44 views

What class of matrices have efficient decompositions?

Suppose we have an arbitrary matrix $A \in \mathbb{C}^{N \times N}$ where $N=2^n$. Now suppose that we can decompose $A$ into tensor products of the Pauli basis given by $A=\sum_{l=0}^Lc_lS_l$ where $...
thespaceman's user avatar
3 votes
0 answers
68 views

Trying to prove Theorem 4.1 from Nielsen and Chuang algebraically

Background Theorem 4.1 of Nielsen and Chuang (10th Anniversary Edition) states how a universal single-qubit unitary can be constructed from Y and Z rotations. Suppose $U$ is a unitary operation on a ...
kaddy's user avatar
  • 31
3 votes
1 answer
2k views

construction of Y gate from X,Z and H gates

As a part of textbook exercise, Y gate is to be constructed using H,Z and X-gates, just like we have $X = HZH$. is there some way/process/intuition to find such combinations or it is just like we need ...
Vinay Sharma's user avatar
4 votes
0 answers
100 views

What is the correct name of this quantum gate? Possibly state control gate

Let $\vec v \in \mathbb{C}^2 $ be the following quantum state: $$ \vec v = \frac{1}{\sqrt{2}}\begin{bmatrix} v_{1} \\ v_{2} \\ \end{bmatrix},\space \lvert v_1 \rvert = 1,...
misanek123's user avatar
2 votes
2 answers
663 views

How do I create an inverse identity gate?

Is it possible for me to construct a gate that inverse everything ($|0\rangle \rightarrow -|0\rangle, |1\rangle \rightarrow -|1\rangle$, etc. basically like a $-I$ gate) from the basic $X, Y, Z, CX,......
Juan's user avatar
  • 604
6 votes
2 answers
2k views

controlled-Z rotation gates in symmetrical fashion

I was going through the qiskit textbook and in this chapter I came across a statement under the topic "Kickback with the T-gate" related to the Controlled-Z gate that the controlled-Z ...
neel.spartacus's user avatar