Quantum speed limit time for moving qubit inside leaky cavity

The shortest time required for a system to transform from an initial state to its orthogonal state is known as the quantum speed limit time. Calculating the QSL time for closed and open systems has been the subject of much recent works. QSL time is inversely related to the evolution rate of the system. In such a way that with increasing this time, the speed of evolution decreases and vice versa. In this work we study the QSL time for moving qubit inside leaky cavity. It is observed that for both weak coupling and strong coupling regimes the QSL time increases with increasing the velocity of the qubit inside the leaky cavity. It is observed that with increasing qubit velocity, the speed of the evolution tends to a constant value and the system becomes more stable.Comment: 10 pages, 3 figur

Enhancing the efficiency of open quantum batteries via adjusting the classical driving field

In the context of quantum information, a quantum battery refers to a system composed of quantum particles that can store and release energy in a way that is governed by the principles of quantum mechanics. The study of open quantum batteries is motivated by the fact that real-world quantum systems are almost never perfectly isolated from their environment. One important challenge in the study of open quantum batteries is to develop theoretical models that accurately capture the complex interactions between the battery and its environment. the goal of studying open quantum batteries is to develop practical methods for building and operating quantum devices that can store and release energy with high efficiency and reliability, even in the presence of environmental noise and other sources of decoherence. The charging process of open quantum batteries under the influence of dissipative environment will be studied. In this Work, the effect of the classical driving field on the charging process of open quantum batteries will be investigated. The classical driving field can be used to manipulate the charging and discharging process of the battery, leading to enhanced performance and improved efficiency. It also will be showed that the efficiency of open quantum batteries depends on detuning between the qubit and the classical driving field and central frequency of the cavity and the classical driving field.Comment: 9 pages, 11 figures. This is just a draft version of the manuscript. We welcome your comments and contribution

Tripartite quantum-memory-assisted entropic uncertainty relations for multiple measurements

It is possible to extend the bipartite quantum-memory-assisted entropic uncertainty relation (QMA-EUR) to the tripartite one in which the memory is split into two parts. The uncertainty relations are usually applied to two incompatible observables, however, many kinds of research have been made to generalize the uncertainty relations to more than two observables. Recently, although many relations have been obtained for bipartite QMA-EUR for multiple measurements, the case of tripartite remains unstudied. In this work, we obtain several tripartite QMA-EURs for multiple measurements and show that the lower bounds of these relations have three terms that depend on the complementarity of the observables, the conditional von-Neumann entropies, the Holevo quantities, and the mutual information. Moreover, it is revealed that one of the terms is related to the strong subadditivity inequality. These uncertainty relations are expected to be helpful in the foundations of quantum theory and quantum information processing.Comment: 14pages, 3 figure

Holevo bound of entropic uncertainty relation under Unruh channel in the context of open quantum systems

The uncertainty principle is the most important feature of quantum mechanics, which can be called the heart of quantum mechanics. This principle sets a lower bound on the uncertainties of two incompatible measurement. In quantum information theory, this principle is expressed in terms of entropic measures. Entropic uncertainty bound can be altered by considering a particle as a quantum memory. In this work we investigate the entropic uncertainty relation under the relativistic motion. In relativistic uncertainty game Alice and Bob agree on two observables, $\widehat{Q}$ and $\widehat{R}$, Bob prepares a particle constructed from the free fermionic mode in the quantum state and sends it to Alice, after sending, Bob begins to move with an acceleration a, then Alice does a measurement on her particle A and announces her choice to Bob, whose task is then to minimize the uncertainty about the measurement outcomes. we will have an inevitable increase in the uncertainty of the Alic’s measurement outcome due to information loss which was stored initially in B. In this work we look at the Unruh effect as a quantum noise and we will characterize it as a quantum channel

Protecting the entropic uncertainty lower bound in Markovian and non-Markovian environment via additional qubits

The uncertainty principle is an important principle in quantum theory. Based on this principle, it is impossible to predict the measurement outcomes of two incompatible observables, simultaneously. The uncertainty principle basically is expressed in terms of the standard deviation of the measured observables. In quantum information theory, it is shown that the uncertainty principle can be expressed by Shannon’s entropy. The entopic uncertainty lower bound can be altered by considering a particle as the quantum memory which is correlated with the measured particle. We assume that the quantum memory is an open system. We also select the quantum memory from N qubit which interact with common reservoir. In this work we investigate the effects of the number of additional qubits in reservoir on entropic uncertainty lower bound. We conclude that the entropic uncertainty lower bound can be protected from decoherence by increasing the number of additional qubit in reservoir

Quantum Speed Limit for a Moving Qubit inside a Leaky Cavity

The quantum speed limit (QSL) is a theoretical lower bound of the time required for a quantum system to evolve from an arbitrary initial state to its orthogonal counterpart. This figure can be used to characterize the dynamics of open quantum systems, including non-Markovian maps. In this paper, we investigate the QSL time for a model that consists of a single qubit moving inside a leaky cavity. Notably, we show that for both weak and strong coupling regimes, the QSL time increases while we boost the velocity of the qubit inside the leaky cavity. Moreover, it is observed that by increasing the qubit velocity, the speed of the evolution tends to a constant value, and the system becomes more stable. The results provide a better understanding of the dynamics of atom-photon couplings and can be used to enhance the controllability of quantum systems