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We develop a general perturbative theory of finite-coupling quantum thermometry up to second order in probe-sample interaction. By assumption, the probe and sample are in thermal equilibrium, so the probe is described by the mean-force…

A large literature has grown up around the proposed use of 'weak measurements' (i.e., unsharp measurements followed by post-selection) to allegedly provide information about hidden ontological features of quantum systems. This paper…

Quantum Physics · Physics 2017-05-16 R. E. Kastner

We propose a method to verify quantum steering for two qubit states with an arbitrary amount of null results when both the steering and steered parties cannot be trusted. We converted the steering inequality proposed in a recent article…

Quantum Physics · Physics 2019-01-16 InU Jeon , Hyunseok Jeong

Monitored quantum systems evolve along stochastic trajectories correlated with the observer's knowledge of the system's state. Under such dynamics, certain quantum resources like entanglement may depend on the observer's state of knowledge.…

Quantum Physics · Physics 2024-09-04 Christian Carisch , Oded Zilberberg , Alessandro Romito

A recent result about measurability of a quantum state of a single quantum system is generalized to the case of a single pre- and post-selected quantum system described by a two-state vector. The protection required for such measurement is…

Quantum Physics · Physics 2007-05-23 Y. Aharonov , L. Vaidman

We consider quantum systems with a Hamiltonian containing a weak perturbation i.e. $\boldsymbol{H=H_0} + \boldsymbol{\lambda} \cdot \boldsymbol{\tilde{H}}$, $\boldsymbol{\lambda}= \{\lambda_1, \lambda_2,...\}$, $\boldsymbol{\tilde{H}}$ $=…

Quantum Physics · Physics 2025-02-18 Sidali Mohammdi , Matteo Bina , Abdelhakim Gharbi , Matteo G. A. Paris

We present a general analytic method for evaluating the generally time-dependent pointer states of a subsystem, which are defined by their capability not to entangle with the states of another subsystem. In this way, we show how in practice…

Quantum Physics · Physics 2011-04-25 Hoofar Daneshvar , G. W. F. Drake

Complementary relationships exist regarding interference properties of particles such as pattern visibility, predictability and distinguishability. Additionally, relationships are known between information gain $G$ and measurement…

Quantum Physics · Physics 2024-09-04 Michael Steiner , Ronald Rendell

We discuss the disturbance by measurements which unambiguously discriminate between given candidate states. We prove that such an optimal measurement necessarily changes distinguishable states indistinguishable when the inconclusive outcome…

Quantum Physics · Physics 2018-03-14 Ryuitiro Kawakubo , Tatsuhiko Koike

The perturbative consistency of coherent states within interacting quantum field theory requires them to be altered beyond the simple non-squeezed form. Building on this point, we perform explicit construction of consistent squeezed…

High Energy Physics - Theory · Physics 2023-12-01 Lasha Berezhiani , Giordano Cintia , Michael Zantedeschi

Quantum measurements necessarily disturb the state of physical system. Once we perform a complete measurement, the system undergoes decoherence and loses its coherence. If there is no disturbance, the state retains all of its coherence. It…

Quantum Physics · Physics 2018-10-10 Gautam Sharma , Arun Kumar Pati

The description of a measuring process, such as that which occurs when a quantum point contact (QPC) detector is influenced by a nearby external electron which can take up two possible positions, provides a interesting application of the…

Quantum Physics · Physics 2008-11-26 L. Stodolsky

Long qubit coherence and efficient atom-photon coupling are essential for advanced applications in quantum communication. One technique to maintain coherence is dynamical decoupling, where a periodic sequence of refocusing pulses is…

Quantum Physics · Physics 2021-02-02 Chang Hoong Chow , Boon Long Ng , Christian Kurtsiefer

The significance of the quantum feature of entanglement between physical systems is investigated in the context of quantum measurements. It is shown that, while there are measurement couplings that leave the object and probe systems…

Quantum Physics · Physics 2011-01-04 P. Busch

We investigate the measurements of two-state quantum systems (qubits) at finite temperatures using a resonant harmonic oscillator as a quantum probe. The reduced density matrix and oscillator correlators are calculated by a scheme combining…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Teemu Ojanen , Tero T. Heikkila

Pointlike systems coupled to quantum fields are often employed as toy models for measurements in quantum field theory. In this paper, we identify the field observables recorded by such models. We show that in models that work in the strong…

Quantum Physics · Physics 2023-08-29 Maria Papageorgiou , Jose de Ramon , Charis Anastopoulos

Utilizing the framework of matrix product states, we investigate gauging as a method for exploring quantum phases of matter. Specifically, we describe how symmetry-protected topological (SPT) phases and spontaneous symmetry breaking (SSB)…

Quantum Physics · Physics 2025-09-08 David Blanik , José Garre-Rubio , Norbert Schuch

We consider a system of linear hyperbolic PDEs where the state at one of the boundary points is controlled using the measurements of another boundary point. Because of the disturbances in the measurement, the problem of designing dynamic…

Systems and Control · Computer Science 2017-07-25 Aneel Tanwani , Christophe Prieur , Sophie Tarbouriech

This work investigates the almost sure stabilization of a class of regime-switching systems based on discrete-time observations of both continuous and discrete components. It develops Shao's work [SIAM J. Control Optim., 55(2017), pp.…

Probability · Mathematics 2018-09-11 Jinghai Shao , Fubao Xi

The dynamics for an open quantum system can be `unravelled' in infinitely many ways, depending on how the environment is monitored, yielding different sorts of conditioned states, evolving stochastically. In the case of ideal monitoring…

Quantum Physics · Physics 2014-11-21 L. Li , A. Chia , H. M. Wiseman