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Related papers: Bayesian Estimation for Bell State Rotations

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We investigate the dynamics of a qubit-oscillator system under the influence of a linear sweep of system parameters. We consider two main cases. In the first case, we consider sweeping the parameters between the regime of a weakly…

Quantum Physics · Physics 2023-09-07 Sahel Ashhab , Tomoko Fuse , Fumiki Yoshihara , Sunmi Kim , Kouichi Semba

The optimal state determination (or tomography) is studied for a composite system of two qubits when measurements can be performed on one of the qubits and interactions of the two qubits can be implemented. The goal is to minimize the…

Quantum Physics · Physics 2009-11-13 D. Petz , K. M. Hangos , A. Szanto , F. Szollosi

A rotating surface can induce a frequency shift in incident light by changing its angular momentum, a phenomenon known as the rotational Doppler effect. This effect provides a means to estimate the angular velocity of the rotating surface.…

In this work we provide a framework that connects the co-rotating and counter rotating $f$-mode frequencies of rotating neutron stars with their stellar structure. The accurate computation of these modes for realistic equations of state has…

General Relativity and Quantum Cosmology · Physics 2021-04-21 Sebastian H. Völkel , Christian J. Krüger , Kostas D. Kokkotas

We consider mixed states of two qubits and show under which global unitary operations their entanglement is maximized. This leads to a class of states that is a generalization of the Bell states. Three measures of entanglement are…

Quantum Physics · Physics 2009-11-06 Frank Verstraete , Koenraad Audenaert , Tijl De Bie , Bart De Moor

We used quantum process tomography to investigate and identify the function of a nonideal two-qubit quantum-state filters subject to various degree of decoherence. We present a simple decoherence model that explains the experimental results…

Quantum Physics · Physics 2009-11-10 Yoshihiro Nambu , Kazuo Nakamura

Bayesian inference is a powerful paradigm for quantum state tomography, treating uncertainty in meaningful and informative ways. Yet the numerical challenges associated with sampling from complex probability distributions hampers Bayesian…

Quantum Physics · Physics 2020-05-04 Joseph M. Lukens , Kody J. H. Law , Ajay Jasra , Pavel Lougovski

The quantum metrological performance of spin coherent states superposition is considered, and conditions for measurements with the Heisenberg-limit (HL) precision are identified. It is demonstrated that the choice of the…

Quantum Physics · Physics 2021-10-26 Yusef Maleki

We study theoretically the properties of two Bose-Einstein condensates in different spin states, represented by a double Fock state. Individual measurements of the spins of the particles are performed in transverse directions, giving access…

Quantum Physics · Physics 2009-11-13 Franck Laloë , William J. Mullin

We consider the problem of estimating a random state vector when there is information about the maximum distances between its subvectors. The estimation problem is posed in a Bayesian framework in which the minimum mean square error (MMSE)…

Statistics Theory · Mathematics 2012-10-30 Dave Zachariah , Isaac Skog , Magnus Jansson , Peter Händel

Rotating wave approximation in a quantum spin system driven by a linearly polarized alternating magnetic field with quadrupole interaction presents is investigated in detail in this paper. The conventional way to employ the rotating wave…

Quantum Physics · Physics 2020-10-16 Wenkui Ding , Xiaoguang Wang

Many superconducting qubit systems use the dispersive interaction between the qubit and a coupled harmonic resonator to perform quantum state measurement. Previous works have found that such measurements can induce state transitions in the…

Optimal phase estimation protocols require complex state preparation and readout schemes, generally unavailable or unscalable in many quantum platforms. We develop and analyze a scheme that achieves near-optimal precision up to a constant…

Quantum Physics · Physics 2026-02-16 Su Direkci , Ran Finkelstein , Manuel Endres , Tuvia Gefen

The real-world applications in signal processing generally involve estimating the system state or parameters in nonlinear, non-Gaussian dynamic systems. The estimation problem may get even more challenging when there are physical…

Signal Processing · Electrical Eng. & Systems 2022-03-15 Nesrine Amor , Ghulam Rasool , Nidhal C. Bouaynaya

High-dimensional quantum entanglement is an essential resource in quantum technology since it provides benefits in increasing the information capacity and processing speed. Thus, the controlled harnessing of high-dimensional entanglement…

Quantum Physics · Physics 2024-12-30 Ling Hong , Yuning Zhang , Yuanyuan Chen , Lixiang Chen

We study the dimension of the manifold of quantum states (called orbit) that a given quantum state of light can reach under the dynamics of linear or Gaussian quantum optics. That is, we investigate how many directions in the Hilbert space…

Quantum Physics · Physics 2026-03-04 Eliott Z. Mamon

We analyze the linear optical realization of number-sum Bell measurement and number-state manipulation by taking into account the realistic experimental situation, specifically imperfectness of single-photon detector. The present scheme for…

Quantum Physics · Physics 2009-11-10 Akira Kitagawa , Katsuji Yamamoto

We propose a scheme for parameter estimation with cluster states. We find that phase estimation with cluster states under a many-body Hamiltonian and separable measurements leads to a precision at the Heisenberg limit. As noise models we…

Quantum Physics · Physics 2009-03-03 Matthias Rosenkranz , Dieter Jaksch

State estimation is usually analyzed in the situation when copies are in a product state, either mixed or pure. We investigate here the concept of state estimation on correlated copies. We analyze state estimation on correlated N qubit…

Quantum Physics · Physics 2009-11-10 Rafal Demkowicz-Dobrzanski

We consider the problem of estimating the state of a large but finite number $N$ of identical quantum systems. In the limit of large $N$ the problem simplifies. In particular the only relevant measure of the quality of the estimation is the…

Quantum Physics · Physics 2008-12-18 R. D. Gill , S. Massar