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We demonstrate that memory in an $N$-qubit system subjected to decoherence, is a potential resource for the slow-down of the entanglement decay. We show that this effect can be used to retain the sub shot-noise sensitivity of the parameter…

Quantum Physics · Physics 2014-12-17 P. Szankowski , M. Trippenbach , J. Chwedenczuk

Amplitude estimation algorithms are based on Grover's algorithm: alternating reflections about the input state and the desired outcome. But what if we are given the ability to perform arbitrary rotations, instead of just reflections? In…

Quantum Physics · Physics 2023-03-08 Patrick Rall , Bryce Fuller

We use continuous, stochastic quantum trajectories within a framework of quantum state diffusion (QSD) to describe alternating measurements of two non-commuting observables. Projective measurement of an observable completely destroys memory…

Quantum Physics · Physics 2024-09-24 Sophia M. Walls , Ian J. Ford

The characterization of the evolution of a quantum system is one of the main tasks to accomplish to achieve quantum information processing. The standard quantum process tomography (SQPT) has the unique property that it can be applied…

Quantum Physics · Physics 2012-12-04 Wu Xiaohua

Entanglement-breaking channels (equivalently, measure-and-prepare channels) are an important class of quantum operations noted for their ability to destroy multipartite spatial quantum correlations. Inspired by this property, they have also…

Quantum Physics · Physics 2025-12-22 Lucas B. Vieira , Huan-Yu Ku , Costantino Budroni

The role of interference and entanglement in quantum neural processing is discussed. It is argued that on contrast to the quantum computing the problem of the use of exponential resources as the payment for the absense of entanglement does…

Quantum Physics · Physics 2015-06-26 A. A. Ezhov

We consider process tomography for unitary quantum channels. Given access to an unknown unitary channel acting on a $\textsf{d}$-dimensional qudit, we aim to output a classical description of a unitary that is $\varepsilon$-close to the…

Quantum Physics · Physics 2024-07-31 Jeongwan Haah , Robin Kothari , Ryan O'Donnell , Ewin Tang

The capability to reliably transmit and store quantum information is an essential building block for future quantum networks and processors. Gauging the ability of a communication link or quantum memory to preserve quantum correlations is…

Quantum Process Tomography (QPT) is a powerful tool to characterize quantum operations, but it requires considerable resources making it impractical for more than 2-qubit systems. This work proposes an alternative approach that requires…

Quantum Physics · Physics 2022-05-18 Vicente Leyton-Ortega , Tyler Kharazi , Raphael C. Pooser

Quantum repeaters promise to deliver long-distance entanglement overcoming noise and loss in realistic quantum channels. A promising class of repeaters, based on atomic ensemble quantum memories and linear optics, follow the proposal by…

Quantum Physics · Physics 2010-04-05 Jonatan Bohr Brask , Anders Sondberg Sorensen

A dynamical model for quantum channel is introduced which allows one to pass continuously from the memoryless case to the case in which memory effects are present. The quantum and classical communication rates of the model are defined and…

Quantum Physics · Physics 2009-11-11 Vittorio Giovannetti

We consider a model of bosonic memory channel, which induces correlations among the transmitted signals. The application of suitable unitary transformations at encoding and decoding stages allows the complete removal of correlations,…

Quantum Physics · Physics 2012-02-01 Cosmo Lupo , Laleh Memarzadeh , Stefano Mancini

Quantum Phase Estimation (QPE) routines are known to fail probabilistically even with perfect gates and input states. This effect stems from an incompatibility of finite-sized quantum registers to capture a phase within QPE with phase…

Quantum Physics · Physics 2025-08-12 Harriet Apel , Cristian L. Cortes , Jessica Lemieux , Mark Steudtner

We study the effect of quantum memory in non-inertial frames under the influence of amplitude damping, depolarizing, phase flip and bit-phase flip channels. It is shown that the entanglement of initial state is heavily influenced by quantum…

Quantum Physics · Physics 2011-03-08 M. Ramzan , M. K. Khan

We present a two-state practical quantum bit commitment protocol, the security of which is based on the current technological limitations, namely the nonexistence of either stable long-term quantum memories or nondemolition measurements.…

Characterizing quantum processes is essential for unlocking the potential of quantum devices. However, standard quantum process tomography is resource-intensive and becomes infeasible on large-scale systems. Despite alternative approaches…

Quantum Physics · Physics 2026-02-24 Hao Zhan , Zongbo Bao , Zekun Ye , Qianyi Wang , Minghao Mi , Penghui Yao , Lijian Zhang

The uncertainty principle sets a bound on our ability to predict the measurement outcomes of two incompatible observables which are measured on a quantum particle simultaneously. In quantum information theory, the uncertainty principle can…

Quantum Physics · Physics 2019-12-03 H. Dolatkhah , S. Haseli , S. Salimi , A. s. Khorashad

Technology based on memristors, resistors with memory whose resistance depends on the history of the crossing charges, has lately enhanced the classical paradigm of computation with neuromorphic architectures. However, in contrast to the…

Quantum Physics · Physics 2017-01-12 P. Pfeiffer , I. L. Egusquiza , M. Di Ventra , M. Sanz , E. Solano

Measurements can be viewed as interactions between a measured system and a pointer system that imprint information about the system on the pointer. For so-called unbiased interactions, the measurement statistics--the information…

Quantum Physics · Physics 2025-03-31 Tiago Debarba , Marcus Huber , Nicolai Friis

Pattern recognition algorithms are commonly employed to simplify the challenging and necessary step of track reconstruction in sub-atomic physics experiments. Aiding in the discrimination of relevant interactions, pattern recognition seeks…

Quantum Physics · Physics 2021-07-14 Gregory Quiroz , Lauren Ice , Andrea Delgado , Travis S. Humble