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Related papers: Krylov complexity of purification

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The notion of complexity of quantum states is quite different from uncertainty or information contents, and involves the tradeoff between its classical and quantum features. In this work, we we introduce a quantifier of complexity of…

Quantum Physics · Physics 2025-11-26 Siting Tang , Francesco Albarelli , Yue Zhang , Shunlong Luo , Matteo G. A. Paris

We derive an exact uncertainty relation for arbitrary quantum states of finite-dimensional Hilbert spaces. For any given $k$-partition of a $d$-dimensional multipartite system, we introduce the total uncertainty as the sum of the…

Quantum Physics · Physics 2026-03-19 G. Tartaglione , G. Zanfardino , F. Illuminati

The ER=EPR conjecture states that quantum entanglement between boundary degrees of freedom leads to the emergence of bulk spacetime itself. Although this has been tested extensively in String Theory for asymptotically anti-de Sitter…

High Energy Physics - Theory · Physics 2025-05-21 Suddhasattwa Brahma , Lucas Hackl , Moatsem Hassan , Xiancong Luo

We define the algorithmic complexity of a quantum state relative to a given precision parameter, and give upper bounds for various examples of states. We also establish a connection between the entanglement of a quantum state and its…

Quantum Physics · Physics 2009-11-11 Caterina Mora , Hans Briegel

Recently, the dynamics of quantum systems that involve both unitary evolution and quantum measurements have attracted attention due to the exotic phenomenon of measurement-induced phase transitions. The latter refers to a sudden change in a…

Quantum Physics · Physics 2025-06-23 Ryotaro Suzuki , Jonas Haferkamp , Jens Eisert , Philippe Faist

Krylov complexity (K-complexity) is a measure of quantum state complexity that minimizes wavefunction spreading across all the possible bases. It serves as a key indicator of operator growth and quantum chaos. In this work, K-complexity and…

Quantum Physics · Physics 2025-10-08 J. Bharathi Kannan , Sreeram PG , Sanku Paul , S. Harshini Tekur , M. S. Santhanam

We give arguments for the existence of a thermodynamics of quantum complexity that includes a "Second Law of Complexity". To guide us, we derive a correspondence between the computational (circuit) complexity of a quantum system of $K$…

High Energy Physics - Theory · Physics 2018-12-07 Adam R. Brown , Leonard Susskind

Open quantum systems host mixed-state phases that go beyond the symmetry-protected topological and spontaneous symmetry-breaking paradigms established for closed, pure-state systems. Developing a unified and physically transparent…

Quantum Physics · Physics 2026-02-26 Yuchen Guo , Shuo Yang

In analogy of classical Kolmogorov complexity we develop a theory of the algorithmic information in bits contained in any one of continuously many pure quantum states: quantum Kolmogorov complexity. Classical Kolmogorov complexity coincides…

Quantum Physics · Physics 2007-05-23 Paul Vitanyi

We develop a theory of the algorithmic information in bits contained in an individual pure quantum state. This extends classical Kolmogorov complexity to the quantum domain retaining classical descriptions. Quantum Kolmogorov complexity…

Quantum Physics · Physics 2016-11-17 Paul M. B. Vitanyi

This work is originally a Cambridge Part III essay paper. Quantum complexity arises as an alternative measure to the Fubini metric between two quantum states. Given two states and a set of allowed gates, it is defined as the least complex…

Quantum Physics · Physics 2021-04-13 Andrea Russo

Uncertainty relations for mixed quantum states (precisely, purity-bounded position-momentum relations, developed by Bastiaans and then by Man'ko and Dodonov) are studied in general multi-dimensional case. An expression for family of mixed…

Quantum Physics · Physics 2007-05-23 Mikalai Karelin

The fidelity and local unitary transformation are two widely useful notions in quantum physics. We study two constrained optimization problems in terms of the maximal and minimal fidelity between two bipartite quantum states undergoing…

Quantum Physics · Physics 2015-11-23 Lin Zhang , Lin Chen , Kaifeng Bu

State transformation problems such as compressing quantum information or breaking quantum commitments are fundamental quantum tasks. However, their computational difficulty cannot easily be characterized using traditional complexity theory,…

Quantum Physics · Physics 2025-07-30 John Bostanci , Yuval Efron , Tony Metger , Alexander Poremba , Luowen Qian , Henry Yuen

In order to resolve the measurement problem of Quantum Mechanics, non-unitary time evolution has been derived from the unitarity of standard quantum formalism. New wave functions of free and non-free quantum systems follow from Schroedinger…

Quantum Physics · Physics 2007-05-23 Pradip Kumar Chatterjee

We prove a rigorous inequality estimating the purity of a reduced density matrix of a composite quantum system in terms of cross-correlation of the same state and an arbitrary product state. Various immediate applications of our result are…

Quantum Physics · Physics 2009-11-10 Tomaz Prosen , Thomas H. Seligman , Marko Znidaric

In this paper, we study the Krylov complexity ($K$) from the planar/inflationary patch of the de Sitter space using the two mode squeezed state formalism in the presence of an effective field having sound speed $c_s$. From our analysis, we…

High Energy Physics - Theory · Physics 2023-06-09 Kiran Adhikari , Sayantan Choudhury

Measurement-based quantum computation has revolutionized quantum information processing, and the physical systems with which it can be implemented. One simply needs the ability to prepare a particular state, known as the cluster state, and…

Quantum Physics · Physics 2008-02-15 Dimitris G. Angelakis , Alastair Kay

We introduce a technique that allows one to connect any two arbitrary (pure or mixed) superposition states of an N-state quantum system. The proposed solution to this inverse quantum mechanical problem is analytical, exact, and very…

Quantum Physics · Physics 2009-11-13 P. A. Ivanov , B. T. Torosov , N. V. Vitanov

We propose the Wigner separability entropy as a measure of complexity of a quantum state. This quantity measures the number of terms that effectively contribute to the Schmidt decomposition of the Wigner function with respect to a chosen…

Quantum Physics · Physics 2012-05-23 Giuliano Benenti , Gabriel G. Carlo , Tomaz Prosen