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Characterizing the memory properties of the environment has become critical for the high-fidelity control of qubits and other advanced quantum systems. However, current non-Markovian tomography techniques are either limited to discrete…

Exchange of information between a quantum system and its surrounding environment plays a fundamental role in the study of the dynamics of open quantum systems. Here we discuss the role of the information exchange in the non-Markovian…

We initiate the study of two-party cryptographic primitives with unconditional security, assuming that the adversary's quantum memory is of bounded size. We show that oblivious transfer and bit commitment can be implemented in this model…

Quantum Physics · Physics 2007-05-23 Ivan Damgaard , Serge Fehr , Louis Salvail , Christian Schaffner

The Lindblad equation is widely employed in studies of Markovian quantum open systems. Here, firstly, a simple result is presented on the time evolution of the non Neumann entropy under the Lindblad equation, which enables one to examine if…

Quantum Physics · Physics 2016-10-18 Congjie Ou , Ralph V. Chamberlin , Sumiyoshi Abe

Theoretical understanding of the scaling of entropies and the mutual information has led to significant advances in the research of correlated states of matter, quantum field theory, and gravity. Measuring von Neumann entropy in quantum…

Non-Markovian quantum processes exhibit different memory effects when measured in different ways; an unambiguous characterization of memory length requires accounting for the sequence of instruments applied to probe the system dynamics.…

Quantum Physics · Physics 2019-04-11 Philip Taranto , Simon Milz , Felix A. Pollock , Kavan Modi

Open quantum systems are inherently coupled to their environments, which in turn also obey quantum dynamical rules. By restricting to dissipative dynamics, here we propose a measure that quantifies how far the environment action on a system…

Quantum Physics · Physics 2023-10-10 Adrián A. Budini

Recently remarkable progress in quantum technology has been witnessed. In view of this it is important to investigate an open quantum system as a model of such quantum devices. Quantum devices often require extreme conditions such as very…

Quantum Physics · Physics 2020-12-02 Shingo Kukita , Yasushi Kondo , Mikio Nakahara

Realistic quantum devices are inherently open and often involve environments with memory. Here, we investigate quantum resource generation in two classes of random circuits, namely, memoryless open and memoryful open random circuits, and…

Quantum Physics · Physics 2026-05-21 Paranjoy Chaki , Arkaprava Sil , Priya Ghosh , Ujjwal Sen , Sudipto Singha Roy

A quantum system inevitably interacts with its surroundings. In general, one does not have detailed information on an environment. Identifying the environmental features can help us to control the environment and its effects on the dynamics…

Quantum Physics · Physics 2017-05-16 F. T. Tabesh , S. Salimi , A. S. Khorashad

We evaluate the quantum witness based on the no-signaling-in-time condition of a damped two-level system for nonselective generalized measurements of varying strength. We explicitly compute its dependence on the measurement strength for a…

Quantum Physics · Physics 2018-11-16 Manuel Bojer , Alexander Friedenberger , Eric Lutz

The aim of this thesis is to advance the theory behind quantum information processing tasks, by deriving fundamental limits on bipartite quantum interactions and dynamics, which corresponds to an underlying Hamiltonian that governs the…

Quantum Physics · Physics 2019-01-18 Siddhartha Das

This paper introduces a numerical framework for establishing lower bounds on the conditional von-Neumann entropy in device-independent quantum cryptography and randomness extraction scenarios. Leveraging a hierarchy of semidefinite programs…

Quantum Physics · Physics 2025-08-22 Gereon Koßmann , René Schwonnek

Open quantum systems are governed by both unitary and non-unitary dynamics, with dissipation arising from the latter. Traditional quantum divergence measures, such as quantum relative entropy, fail to account for the non-unitary oriented…

Quantum Physics · Physics 2025-09-23 Tomohiro Nishiyama , Yoshihiko Hasegawa

We compare the thermodynamic entropy of a quantum Brownian oscillator derived from the partition function of the subsystem with the von Neumann entropy of its reduced density matrix. At low temperatures we find deviations between these two…

Quantum Physics · Physics 2009-11-13 Christian Hoerhammer , Helmut Buettner

Fault-tolerant quantum computing requires extremely precise knowledge and control of qubit dynamics during the application of a gate. We develop a data-driven learning protocol for characterizing quantum gates that builds off previous work…

Recently, a large class of quantum non-Markovian piecewise dynamics for an open quantum system obeying closed evolution equations has been introduced [B. Vacchini, Phys. Rev. Lett. 117, 230401 (2016)]. These dynamics have been defined in…

Quantum Physics · Physics 2018-01-17 Salvatore Lorenzo , Francesco Ciccarello , G. Massimo Palma , Bassano Vacchini

We investigate the dynamics for a two level atomic system entangled to coherent states using the recently developed mode invisibility technique. Using a quantum 2-level probe, we demonstrate a way to non-destructively measure a number of…

Quantum Physics · Physics 2017-10-04 Paulina Corona-Ugalde , Marvellous Onuma-Kalu , Robert B. Mann

After a brief introduction to the concept of entanglement in quantum systems, I apply these ideas to many-body systems and show that the von Neumann entropy is an effective way of characterising the entanglement between the degrees of…

Statistical Mechanics · Physics 2009-11-13 John Cardy

We introduce the concept of fidelity for dynamical maps in an open quantum system scenario. We derive an inequality linking this quantity to the distinguishability of the inducing environmental states. Our inequality imposes constraints on…

Quantum Physics · Physics 2017-05-10 Mikko Tukiainen , Henri Lyyra , Gniewomir Sarbicki , Sabrina Maniscalco