Signal transformation ยท Primitives
Polynomial transformation on block encodings (Hermitian, real with parity)
Theorem statement
Let $m,n,L\geq0$ be integers,
$P=\sum_{j=0}^{L}c_jx^j$ be a degree-$L$ real polynomial
with parity $L\bmod2$ such that $|P(x)|\leq1$ for every
$x\in[-1,1]$, and $U$ be a $(1,m,0)$-block-encoding
of an $n$-qubit Hermitian matrix $A$.
Given access to $U$ and $U^\dagger$, there exists
a quantum circuit $\mathcal V$ that implements
a $(1,m+1,0)$-block-encoding of
$P(A)=\sum_{j=0}^{L}c_jA^j$, using at most
1 ancilla qubit, $L$ queries to $U$ and $U^\dagger$,
$192mL$ CNOT gates, and $((296m+3)L+2)$ single-qubit gates.
- $P$
- Polynomial applied to the encoded Hermitian matrix.
Sources
- Quantum singular value transformation and beyond: exponential improvements for quantum matrix arithmetics
Andras Gilyen, Yuan Su, Guang Hao Low, Nathan Wiebe, 2019
Lean context
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