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We present a quantum algorithm for systems of (possibly inhomogeneous) linear ordinary differential equations with constant coefficients. The algorithm produces a quantum state that is proportional to the solution at a desired final time.…

Quantum Physics · Physics 2017-11-07 Dominic W. Berry , Andrew M. Childs , Aaron Ostrander , Guoming Wang

Quantum computers can execute algorithms that sometimes dramatically outperform classical computation. Undoubtedly the best-known example of this is Shor's discovery of an efficient quantum algorithm for factoring integers, whereas the same…

Quantum Physics · Physics 2017-08-23 Wim van Dam , Yoshitaka Sasaki

In this work, we propose a new way to (non-interactively, verifiably) demonstrate quantum advantage by solving the average-case $\mathsf{NP}$ search problem of finding a solution to a system of (underdetermined) constant degree multivariate…

Quantum Physics · Physics 2025-09-10 Pierre Briaud , Itai Dinur , Riddhi Ghosal , Aayush Jain , Paul Lou , Amit Sahai

Quantum mechanics allows for coherent control over the order in which different processes take place on a target system, giving rise to a new feature known as indefinite causal order. Indefinite causal order provides a resource for quantum…

In this paper we give a polynomial-time quantum algorithm for computing orders of solvable groups. Several other problems, such as testing membership in solvable groups, testing equality of subgroups in a given solvable group, and testing…

Quantum Physics · Physics 2007-05-23 John Watrous

The precision of quantum metrology is widely believed to be restricted by the Heisenberg limit, corresponding to a root mean square error that is inversely proportional to the number of independent processes probed in an experiment, N. In…

Quantum supermaps are transformations that map quantum operations to quantum operations. It is known that quantum supermaps which respect a definite, predefined causal order between their input operations correspond to fixed-order quantum…

Quantum Physics · Physics 2023-06-21 Julian Wechs , Hippolyte Dourdent , Alastair A. Abbott , Cyril Branciard

Understanding the physical world fundamentally relies on the assumption that events are temporally ordered, with past events serving as causes for future ones. However, quantum mechanics permits events to occur in a superposition of causal…

Quantum Physics · Physics 2025-08-07 Dengke Qu , Quan Lin , Lei Xiao , Xiang Zhan , Peng Xue

Recent results by Harrow et. al. and by Ta-Shma, suggest that quantum computers may have an exponential advantage in solving a wealth of linear algebraic problems, over classical algorithms. Building on the quantum intuition of these…

Quantum Physics · Physics 2017-04-07 Michael Ben-Or , Lior Eldar

In the black-box model, problems constrained by a `promise' are the only ones that admit a quantum exponential speedup over the best classical algorithm in terms of query complexity. The most prominent example of this is the Deutsch-Jozsa…

Quantum Physics · Physics 2007-05-23 Adam Brazier , Martin B. Plenio

We describe the experimental implementation of a recently proposed quantum algorithm involving quantum entanglement at the level of two qubits using NMR. The algorithm solves a generalisation of the Deutsch problem and distinguishes between…

Quantum Physics · Physics 2009-11-06 Kavita Dorai , Arvind , Anil Kumar

A long-standing aim of quantum information research is to understand what gives quantum computers their advantage. This requires separating problems that need genuinely quantum resources from those for which classical resources are enough.…

Quantum Physics · Physics 2018-03-07 Niklas Johansson , Jan-Åke Larsson

It was recently found that the indefinite causal order in the quantum switch can be certified device-independently when assuming the impossibility of superluminal influences. Here we strengthen this result in two ways. First, we give a…

Quantum Physics · Physics 2024-12-04 Tein van der Lugt , Nick Ormrod

Modern machine learning (ML) methods typically fail to adequately capture causal information. Consequently, such models do not handle data distributional shifts, are vulnerable to adversarial examples, and often learn spurious correlations.…

Quantum Physics · Physics 2026-01-27 Rishi Goel , Casey R. Myers , Sally Shrapnel

In this "map" we are going to present the concept of indefinite causal order and make a quick journey through its different flavours. We will start with a broad conceptual motivation for studying indefinite causal order, based on the…

Quantum Physics · Physics 2025-06-06 Jorge Escandón-Monardes

We demonstrate non-classical cooling on the IBMq cloud quantum computer. We implement a recently proposed refrigeration protocol which relies upon indefinite causal order for its quantum advantage. We use quantum channels which, when used…

Quantum Physics · Physics 2021-11-29 David Felce , Vlatko Vedral , Felix Tennie

A redundancy in the existing Deutsch-Jozsa quantum algorithm is removed and a refined algorithm, which reduces the size of the register and simplifies the function evaluation, is proposed. The refined version allows a simpler analysis of…

Quantum Physics · Physics 2009-10-31 David Collins , K. W. Kim , W. C. Holton

Recent frameworks describing quantum mechanics in the absence of a global causal order admit the existence of causally indefinite processes, where it is impossible to ascribe causal order for events A and B. These frameworks even allow for…

Quantum Physics · Physics 2021-05-11 Simon Milz , Dominic Jurkschat , Felix A. Pollock , Kavan Modi

The phenomenon of quantum entanglement is fundamental to the implementation of quantum computation, and requires at least two qubits for its demonstration. However, both Deutsch algorithm and Grover's search algorithm for two bits do not…

Quantum Physics · Physics 2007-05-23 Arvind , N. Mukunda

We propose a genetic-algorithm-based method to find the unitary transformations for any desired quantum computation. We formulate a simple genetic algorithm by introducing the "genetic parameter vector" of the unitary transformations to be…

Quantum Physics · Physics 2015-01-08 Jeongho Bang , Seokwon Yoo