5 papers
Quantum Purity Amplification for Arbitrary Eigenstates and Multiple Outputs
Zhaoyi Li, Elias Theil, Aram W. Harrow +1
Quantum purity amplification (QPA) is the task of coherently transforming copies of a mixed state into high-fidelity copies of a chosen eigenstate. We develop a general theory…
An Exponential Sample-Complexity Advantage for Coherent Quantum Inference
Zhaoyi Li, Elias Theil, Aram W. Harrow +1
Standard quantum inference converts quantum data into classical outputs. We study an alternative inference setting in which the desired output is quantum. Such settings include qua…
Classification and implementation of unitary-equivariant and permutation-invariant quantum channels
Laura Mančinska, Elias Theil
Many quantum information tasks use inputs of the form , which naturally induce permutation and unitary symmetries. We classify all quantum channels that respect both…
Sample Optimal and Memory Efficient Quantum State Tomography
Yanglin Hu, Enrique Cervero-Martín, Elias Theil +2
Quantum state tomography is the fundamental physical task of learning a complete classical description of an unknown state of a quantum system given coherent access to many identic…
A memory and gate efficient algorithm for unitary mixed Schur sampling
Enrique Cervero-Martín, Laura Mančinska, Elias Theil
We formalize the task of unitary Schur sampling -- an extension of weak Schur sampling -- which is the process of measuring the Young label and the unitary group register of an inp…