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In 1986, Saks and Wigderson conjectured that the largest separation between deterministic and zero-error randomized query complexity for a total boolean function is given by the function $f$ on $n=2^k$ bits defined by a complete binary tree…

Computational Complexity · Computer Science 2015-10-27 Andris Ambainis , Kaspars Balodis , Aleksandrs Belovs , Troy Lee , Miklos Santha , Juris Smotrovs

Quantum error correction is an essential ingredient for universal quantum computing. Despite tremendous experimental efforts in the study of quantum error correction, to date, there has been no demonstration in the realisation of universal…

A long-investigated problem in circuit complexity theory is to decompose an $n$-input or $n$-variable Majority Boolean function (call it $M_n$) using $k$-input ones ($M_k$), $k < n$, where the objective is to achieve the decomposition using…

Logic in Computer Science · Computer Science 2025-04-07 Anupam Chattopadhyay , Debjyoti Bhattacharjee , Subhamoy Maitra

There is currently a significant need for robust and efficient methods for characterizing quantum devices. While there has been significant progress in this direction, there remains a crucial need to precisely determine the strength and…

Quantum Physics · Physics 2019-09-04 Arnaud Carignan-Dugas , Joel J. Wallman , Joseph Emerson

Decision trees are one of the most fundamental computational models for computing Boolean functions $f : \{0, 1\}^n \mapsto \{0, 1\}$. It is well-known that the depth and size of decision trees are closely related to time and number of…

Computational Complexity · Computer Science 2025-01-03 Deepu Benson , Balagopal Komarath , Jayalal Sarma , Nalli Sai Soumya

By using a new way to encode Boolean functions in a reversible gate, an algorithm is developed in quantum computing over Z_2, symbolized QC/2, (as opposed to QC over C) that needs only one function evaluation to solve the Grover Database…

Quantum Physics · Physics 2024-09-09 David Ellerman

We show that sharp thresholds for Boolean functions directly imply average-case circuit lower bounds. More formally we show that any Boolean function exhibiting a sharp enough threshold at \emph{arbitrary} critical density cannot be…

Computational Complexity · Computer Science 2024-07-17 David Gamarnik , Elchanan Mossel , Ilias Zadik

In this paper we study the complexity of quantum query algorithms computing the value of Boolean function and its relation to the degree of algebraic polynomial representing this function. We pay special attention to Boolean functions with…

Quantum Physics · Physics 2012-03-24 Alina Dubrovska Vasilieva , Taisija Mischenko-Slatenkova

In this work, we initiate the study of the Minimum Circuit Size Problem (MCSP) in the quantum setting. MCSP is a problem to compute the circuit complexity of Boolean functions. It is a fascinating problem in complexity theory -- its…

Quantum Physics · Physics 2021-09-15 Nai-Hui Chia , Chi-Ning Chou , Jiayu Zhang , Ruizhe Zhang

A pure state of fixed Hamming weight is a superposition of computational basis states such that each bitstring in the superposition has the same number of ones. Given a Hilbert space of the form $\mathcal{H} = (\mathbb{C}_2)^{\otimes n}$,…

Quantum Physics · Physics 2025-01-22 Soorya Rethinasamy , Margarite L. LaBorde , Mark M. Wilde

The Quantum Approximate Optimization Algorithm, QAOA, uses a shallow depth quantum circuit to produce a parameter dependent state. For a given combinatorial optimization problem instance, the quantum expectation of the associated cost…

Quantum Physics · Physics 2018-12-12 Fernando G. S. L. Brandao , Michael Broughton , Edward Farhi , Sam Gutmann , Hartmut Neven

We propose a new quantum circuit for the quantum search problem. The quantum circuit is superior to Grover's algorithm in some realistic cases. The reasons for the superiority are in short as follows: In the quantum circuit proposed in this…

Quantum Physics · Physics 2020-07-20 Go Kato

Quantum state discrimination between two wave functions on a ring is considered. The optimal minimum-error probability is known to be given by the Helstrom bound. A new strategy is introduced by inserting instantaneously two impenetrable…

Quantum Physics · Physics 2024-11-08 Bernhard K. Meister

We show how an upper bound for the ability to discriminate any number N of candidates for the Hamiltonian governing the evolution of an open quantum system may be calculated by numerically efficient means. Our method applies an effective…

Quantum Physics · Physics 2018-05-23 Alexander Holm Kiilerich , Klaus Mølmer

We derive an algebraic framework which identifies the minimal information required to assess how well a quantum device implements a desired quantum operation. Our approach is based on characterizing only the unitary part of an open system's…

Quantum Physics · Physics 2013-10-10 Daniel M. Reich , Giulia Gualdi , Christiane P. Koch

One of the most fascinating aspects of quantum mechanics is the principle impossibility of deterministic errorless discrimination of nonorthogonal signals, such as coherent states. On the one hand, it prevents perfect cloning of quantum…

Quantum Physics · Physics 2017-01-10 Denis Sych , Gerd Leuchs

We investigate the randomized decision tree complexity of a specific class of read-once threshold functions. A read-once threshold formula can be defined by a rooted tree, every internal node of which is labeled by a threshold function…

Computational Complexity · Computer Science 2023-10-19 Nikos Leonardos

Developing optimal strategies to calibrate quantum processors for high-fidelity operation is one of the outstanding challenges in quantum computing today. Here, we demonstrate multiple examples of high-fidelity operations achieved using a…

Here we show how universal quantum computers based on the quantum circuit model can handle mathematical analysis calculations for functions with continuous domains, without any digitalization, and with remarkably few qubits. The basic…

Quantum Physics · Physics 2022-10-10 Pablo Bermejo , Roman Orus

This paper addresses the problem of designing universal quantum circuits to transform $k$ uses of a $d$-dimensional unitary input-operation into a unitary output-operation in a probabilistic heralded manner. Three classes of protocols are…

Quantum Physics · Physics 2020-04-16 Marco Túlio Quintino , Qingxiuxiong Dong , Atsushi Shimbo , Akihito Soeda , Mio Murao