English
Related papers

Related papers: Reversible Mapping for Tree Structured Quantum Com…

200 papers

Space-time in quantum mechanics is about bridging Hilbert and configuration space. Thereby, an entirely new perspective is obtained by replacing the Newtonian space-time theater with the image of a presumably high-dimensional Hilbert space,…

Quantum Physics · Physics 2024-04-05 Karl Svozil

We consider the task of deciding whether an unknown qubit state falls in a prescribed neighborhood of a reference state. We assume that several copies of the unknown state are given and apply a unitary operation pairwise on them combined…

Quantum Physics · Physics 2018-08-27 Orsolya Kálmán , Tamás Kiss

Current quantum computer designs will not scale. To scale beyond small prototypes, quantum architectures will likely adopt a modular approach with clusters of tightly connected quantum bits and sparser connections between clusters. We…

Quantum Physics · Physics 2020-05-26 Jonathan M. Baker , Casey Duckering , Alexander Hoover , Frederic T. Chong

We revisit quantum tomography in an informationally incomplete scenario and propose improved state reconstruction methods using deep neural networks. In the first approach, the trained network predicts an optimal linear or quadratic…

Quantum Physics · Physics 2026-01-21 Mateusz Krawczyk , Pavel Baláž , Katarzyna Roszak , Jarosław Pawłowski

The complexity of a quantum state may be closely related to the usefulness of the state for quantum computation. We discuss this link using the tree size of a multiqubit state, a complexity measure that has two noticeable (and, so far,…

Quantum Physics · Physics 2016-02-11 Yu Cai , Huy Nguyen Le , Valerio Scarani

In this paper we propose and study a new complexity model for approximation algorithms. The main motivation are practical problems over large data sets that need to be solved many times for different scenarios, e.g., many multicast trees…

Data Structures and Algorithms · Computer Science 2010-06-18 Marek Cygan , Lukasz Kowalik , Marcin Mucha , Marcin Pilipczuk , Piotr Sankowski

We consider algebras underlying Hilbert spaces used by quantum information algorithms. We show how one can arrive at equations on such algebras which define n-dimensional Hilbert space subspaces which in turn can simulate quantum systems on…

Quantum Physics · Physics 2007-05-23 Mladen Pavicic

Ordinary approach to quantum algorithm is based on quantum Turing machine or quantum circuits. It is known that this approach is not powerful enough to solve NP-complete problems. In this paper we study a new approach to quantum algorithm…

Quantum Physics · Physics 2015-06-26 Masanori Ohya , Igor V. Volovich

Motivated by understanding the power of quantum computation with restricted number of qubits, we give two complete characterizations of unitary quantum space bounded computation. First we show that approximating an element of the inverse of…

Quantum Physics · Physics 2016-11-22 Bill Fefferman , Cedric Yen-Yu Lin

The principle of maximum likelihood reconstruction has proven to yield satisfactory results in the context of quantum state tomography for many-body systems of moderate system sizes. Until recently, however, quantum state tomography has…

Quantum Physics · Physics 2014-01-29 Tillmann Baumgratz , Alexander Nüßeler , Marcus Cramer , Martin B. Plenio

We propose a scalable scheme for optical quantum computing using measurement-induced continuous-variable quantum gates in a loop-based architecture. Here, time-bin-encoded quantum information in a single spatial mode is deterministically…

Quantum Physics · Physics 2017-09-27 Shuntaro Takeda , Akira Furusawa

Combinatorial optimization is considered a promising class of problems in which quantum computers can show significant advantages. However, problems of practical relevance typically have more variables than current or foreseeable quantum…

Quantum Physics · Physics 2025-12-23 Mathias Schmid , Naeimeh Mohseni , Michael J. Hartmann

We revisit the application of neural networks techniques to quantum state tomography. We confirm that the positivity constraint can be successfully implemented with trained networks that convert outputs from standard feed-forward neural…

Quantum Physics · Physics 2022-07-20 D. Koutny , L. Motka , Z. Hradil , J. Rehacek , L. L. Sanchez-Soto

In classical computation, a problem can be solved in multiple steps where calculated results of each step can be copied and used repeatedly. While in quantum computation, it is difficult to realize a similar multi-step computation process…

Quantum Physics · Physics 2023-01-19 Hefeng Wang , Sixia Yu , Hua Xiang

In this work, quantum state transfer (QST) over binary-tree spin networks is studied by using advantages of partially collapsing measurements. To this aim, we perform initially a weak measurement (WM) on central qubit of the binary-tree…

Quantum Physics · Physics 2020-07-28 Naghi Behzadi , Bahram Ahansaz

It is well-known that any two pure quantum states (in the same Hilbert space) can be mapped to any other using unitary transformations. However, previous approaches to this problem required two explicit bases for the Hilbert space, one each…

Quantum Physics · Physics 2026-04-20 Peter T. J. Bradshaw , Marcus Gouveia , Jonte R. Hance

Presented here is a matrix inversion method utilizing quantum searching algorithm. In this method, huge Hilbert space as a whole spanned by myriad of eigen states is searched and evaluated efficiently by sequential reduction in dimension…

Quantum Physics · Physics 2007-05-23 Atsushi Miyauchi

In the field of algorithmic analysis, one of the more well-known exercises is the subset sum problem. That is, given a set of integers, determine whether one or more integers in the set can sum to a target value. Aside from the brute-force…

Data Structures and Algorithms · Computer Science 2016-05-09 Daniel Shea

We survey results of a quarter century of work on computation by reversible general-purpose computers (in this setting Turing machines), and general reversible simulation of irreversible computations, with respect to energy-, time- and…

Computational Complexity · Computer Science 2007-05-23 Paul Vitanyi

We show how to perform reversible universal quantum computation on a translationally invariant pure state, using only global operations based on next-neighbor interactions. We do not need not to break the translational symmetry of the state…

Quantum Physics · Physics 2009-11-11 K. G. H. Vollbrecht , J. I. Cirac