Apply a weighted sum of unitaries to a quantum state via PREPARE and SELECT circuits.
npx skills add https://github.com/unitarylab/quantum-skills --skill lcu
Please help me install this Agent Skill. Skill: lcu Source: https://github.com/unitarylab/quantum-skills/tree/main/algorithms/linear-systems/lcu Command: npx skills add https://github.com/unitarylab/quantum-skills --skill lcu
Efficiently apply a weighted sum of unitaries to a quantum state by constructing a PREPARE circuit on an ancilla register and using a SELECT operator, enabling access to non-unitary operations through probabilistic post-selection.
Initialize alphas and unitaries, then run the LCU algorithm to apply the weighted sum of unitaries to your system.
High-intent search queries and answers about installing and using this skill.
To apply a weighted sum of unitaries to a quantum state, you use the LCU method. It encodes weights into an ancilla register via a PREPARE circuit and applies operators conditionally using a SELECT workflow to realize the operation.
The PREPARE SELECT UNPREPARE workflow is an LCU technique for quantum linear solvers. PREPARE encodes coefficients into an ancilla register, SELECT multiplexes unitary applications, and UNPREPARE disentangles the ancilla to enable non-unitary operations via post-selection.
You implement amplitude encoding by constructing a state-preparation tree on an ancilla register using Ry and McRy gates. This encodes specified weights into ancilla amplitudes for subsequent controlled multiplexed unitary applications.
Yes, LCU works for Hamiltonian simulation and QSVT subroutines. By applying a weighted sum of unitaries through controlled multiplexed applications, it serves as a foundational building block across common quantum software stacks.
Yes, quantum linear-system solving with LCU requires controlled unitaries, a properly sized ancilla register, and a normalization factor equal to the sum of your weights. These ensure amplitude encoding and post-selection function correctly.
The primary limitation of LCU for non-unitary operations is reliance on probabilistic post-selection. You must successfully disentangle the ancilla register and measure the correct state, which introduces inherent success probability and potential overhead.
loanntcGenerate cross-sectional multi-factor stock rankings and TopN portfolios from time-series inputs.
unitarylabOrganize quantum algorithm demos with YAML frontmatter and Markdown instructions.
LogauaEngstromBuild, transpile, and execute quantum circuits using Qiskit.
QuantumBFSSelect optimal simulation backends for quantum circuits based on memory and complexity.
