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Using the path integral associated to a cMERA tensor network, we provide an operational definition for the complexity of a cMERA circuit/state which is relevant to investigate the complexity of states in quantum field theory. In this…

High Energy Physics - Theory · Physics 2018-08-07 J. Molina-Vilaplana , A. del Campo

Functional measures for lattice quantum gravity should agree with their continuum counterparts in the weak field, low momentum limit. After showing that the standard simplicial measure satisfies the above requirement, we prove that a class…

High Energy Physics - Theory · Physics 2016-08-25 H. W. Hamber , R. M Williams

An elementary application of Algorithmic Complexity Theory to the polygonal approximations of curved billiards-integrable and chaotic-unveils the equivalence of this problem to the procedure of quantization of classical systems: the scaling…

chao-dyn · Physics 2009-10-31 Giorgio Mantica

Coherent control errors, for which ideal Hamiltonians are perturbed by unknown multiplicative noise terms, are a major obstacle for reliable quantum computing. In this paper, we present a framework for analyzing the robustness of quantum…

Quantum Physics · Physics 2024-12-04 Julian Berberich , Daniel Fink , Christian Holm

Based on general and minimal properties of the {\it discrete} circuit complexity, we define the complexity in {\it continuous} systems in a geometrical way. We first show that the Finsler metric naturally emerges in the geometry of the…

High Energy Physics - Theory · Physics 2019-02-19 Run-Qiu Yang , Yu-Sen An , Chao Niu , Cheng-Yong Zhang , Keun-Young Kim

Quantum complexity measures the difficulty of realizing a quantum process, such as preparing a state or implementing a unitary. We present an approach to quantifying the thermodynamic resources required to implement a process if the…

We extend the definitions of complexity measures of functions to domains such as the symmetric group. The complexity measures we consider include degree, approximate degree, decision tree complexity, sensitivity, block sensitivity, and a…

Computational Complexity · Computer Science 2020-10-16 Neta Dafni , Yuval Filmus , Noam Lifshitz , Nathan Lindzey , Marc Vinyals

The intention of this thesis is to provide general tools and concepts that allow to perform a mathematically substantiated symmetry reduction in (quantum) gauge field theories. Here, the main focus is on the framework of loop quantum…

Mathematical Physics · Physics 2016-01-22 Maximilian Hanusch

Conventional methods of quantum simulation involve trade-offs that limit their applicability to specific contexts where their use is optimal. In particular, the interaction picture simulation has been found to provide substantial asymptotic…

Quantum Physics · Physics 2022-08-17 Abhishek Rajput , Alessandro Roggero , Nathan Wiebe

The recent development of general quantum resource theories has given a sound basis for the quantification of useful quantum effects. Nevertheless, the evaluation of a resource measure can be highly non-trivial, involving an optimisation…

Cumulative memory -- the sum of space used per step over the duration of a computation -- is a fine-grained measure of time-space complexity that was introduced to analyze cryptographic applications like password hashing. It is a more…

Computational Complexity · Computer Science 2023-07-06 Paul Beame , Niels Kornerup

Quantum-inspired classical algorithms provide us with a new way to understand the computational power of quantum computers for practically-relevant problems, especially in machine learning. In the past several years, numerous efficient…

Quantum Physics · Physics 2025-01-15 Nikhil S. Mande , Changpeng Shao

We initiate the study of parameterized complexity of $\textsf{QMA}$ problems in terms of the number of non-Clifford gates in the problem description. We show that for the problem of parameterized quantum circuit satisfiability, there exists…

Quantum Physics · Physics 2023-07-13 Srinivasan Arunachalam , Sergey Bravyi , Chinmay Nirkhe , Bryan O'Gorman

Computational complexity is a new quantum information concept that may play an important role in holography and in understanding the physics of the black hole interior. We consider quantum computational complexity for $n$ qubits using…

High Energy Physics - Theory · Physics 2021-05-21 Roberto Auzzi , Stefano Baiguera , G. Bruno De Luca , Andrea Legramandi , Giuseppe Nardelli , Nicolò Zenoni

This article sheds new light on the problem of cosmological reduction in Loop Quantum Gravity. We critically analyze Quantum Reduced Loop Gravity -- an attempt to extract the cosmological sector of the full theory. We reconsider the…

General Relativity and Quantum Cosmology · Physics 2021-01-12 Jakub Bilski , Antonino Marciano

Clifford gates are a winsome class of quantum operations combining mathematical elegance with physical significance. The Gottesman-Knill theorem asserts that Clifford computations can be classically efficiently simulated but this is true…

Quantum Physics · Physics 2013-06-04 Richard Jozsa , Maarten Van den Nest

The concept of quantum complexity has far-reaching implications spanning theoretical computer science, quantum many-body physics, and high energy physics. The quantum complexity of a unitary transformation or quantum state is defined as the…

High Energy Physics - Theory · Physics 2021-08-02 Fernando G. S. L. Brandão , Wissam Chemissany , Nicholas Hunter-Jones , Richard Kueng , John Preskill

The "quantum complexity" of a unitary operator measures the difficulty of its construction from a set of elementary quantum gates. While the notion of quantum complexity was first introduced as a quantum generalization of the classical…

Quantum Physics · Physics 2021-11-02 Vir B. Bulchandani , S. L. Sondhi

While fundamental physically realistic Hamiltonians should be invariant under time reversal, time asymmetric Hamiltonians can occur as mathematical possibilities or effective Hamiltonians. Here, we study conditions under which…

Quantum Physics · Physics 2019-08-01 Julian Schmidt , Roderich Tumulka

We investigate the emergence of quantum complexity and chaos in doped Clifford circuits acting on qudits of odd prime dimension $d$. Using doped Clifford Weingarten calculus and a replica tensor network formalism, we derive exact results…

Quantum Physics · Physics 2025-12-24 Beatrice Magni , Xhek Turkeshi