5 papers · 1 filter
No low-degree tests for quantum states
Omar Alrabiah, Srinivasan Arunachalam, Sabee Grewal +1
We study the problem of testing low-degree phase states, namely m-qudit quantum states of the form , where is a degree- po…
Learning the structure of open quantum systems
Laura Lewis, Ewin Tang, John Wright
We design an algorithm for learning the coefficients of an -qubit constant-local Lindbladian to error with total evolution time,…
Are controlled unitaries helpful?
Ewin Tang, John Wright
Many quantum algorithms, to compute some property of a unitary , require access not just to , but to , the unitary with a control qubit. We show that having access to $cU…
Amplitude amplification and estimation require inverses
Ewin Tang, John Wright
We prove that the generic quantum speedups for brute-force search and counting only hold when the process we apply them to can be efficiently inverted. The algorithms speeding up t…
Beating full state tomography for unentangled spectrum estimation
Angelos Pelecanos, Xinyu Tan, Ewin Tang +1
How many copies of a mixed state are needed to learn its spectrum? To date, the best known algorithms for spectrum estimation require as many copies…