John Wright

collaborators

7 papers

quant-ph2026

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 $q^{- m /2} \sum_{x \in F_{q}^{m}} I ¨ ^{f (x)} ∣ x >$ , where $f$ is a degree- $d$ p…

quant-ph2026

Learning the structure of open quantum systems

Laura Lewis, Ewin Tang, John Wright

We design an algorithm for learning the coefficients of an $n$ -qubit constant-local Lindbladian to $ε$ error with $O (g d^{2} lo g (n) / ε^{2})$ total evolution time,…

quant-ph2026

Nonasymptotic bounds for quantum purity amplification

Thilo Scharnhorst, Jack Spilecki, John Wright

In quantum purity amplification, one is given $n$ copies of a noisy quantum state $I ¨ \in C^{d \times d}$ and asked to prepare $k$ copies of its principal eigenstate $|v_d\…

quant-ph2026

Conjugate queries can help

Ewin Tang, John Wright, Mark Zhandry

We give a natural problem over input quantum oracles $U$ which cannot be solved with exponentially many black-box queries to $U$ and $U^{†}$ , but which can be solved with const…

quant-ph2026

Are controlled unitaries helpful?

Ewin Tang, John Wright

Many quantum algorithms, to compute some property of a unitary $U$ , require access not just to $U$ , but to $c U$ , the unitary with a control qubit. We show that having access to $cU…

quant-ph2026

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…