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In the quantum Zeno effect, quantum measurements can block the coherent oscillation of a two level system by freezing its state to one of the measurement eigenstates. The effect is conventionally controlled by the measurement frequency.…

Quantum Physics · Physics 2020-10-06 Kyrylo Snizhko , Parveen Kumar , Alessandro Romito

We consider a single copy of a quantum particle moving in a potential and show that it is possible to monitor its complete wave function by only continuously measuring its position. While we assume that the potential is known, no…

Quantum Physics · Physics 2015-05-13 Thomas Konrad , Andreas Rothe , Francesco Petruccione , Lajos Diósi

Entanglement is a fundamental feature of quantum mechanics and holds great promise for enhancing metrology and communications. Much of the focus of quantum metrology so far has been on generating highly entangled quantum states that offer…

Here we propose an implementation of all possible Positive Operator Value Measures (POVMs) of two-photon polarization states. POVMs are the most general class of quantum measurements. Our setup requires linear optics, Bell State…

Quantum Physics · Physics 2009-11-11 S. E. Ahnert , M. C. Payne

Pushing forward the understanding of general non-unitary dynamics in controlled quantum platforms has been fueled by the recent discovery of measurement-induced phases and phase transitions. So far, these transitions remained largely…

Disordered Systems and Neural Networks · Physics 2022-08-24 M. Buchhold , T. Müller , S. Diehl

Quantum information has been drawing a wealth of research in recent years, shedding light on questions at the heart of quantum mechanics, as well as advancing fields such as complexity theory, cryptography, key distribution, and chemistry.…

Quantum Physics · Physics 2017-04-25 Dikla Oren , Maor Mutzafi , Yonina C. Eldar , Mordechai Segev

Generally, the measurement process consists in coupling a system to a detector that can give a continuous output. However, it may be interesting to use as a detector a system with a discrete spectrum, especially in view of applications to…

Quantum Physics · Physics 2013-02-06 Antonio Di Lorenzo

Classically, no transfer occurs between two equally filled reservoirs no matter how one looks at them, but the situation can be different quantum mechanically. This paradoxically surprising phenomenon rests on the distinctive property of…

Quantum Physics · Physics 2015-06-19 Antoine Tilloy , Michel Bauer , Denis Bernard

We propose a protocol to test whether the postulate of a measurement acting as an instantaneous projection onto an eigenstate of the measurement apparatus is compatible with physical reality. This approach is solely based on repeated…

Quantum Physics · Physics 2025-06-26 Leonard Werner Pingen , Mattia Moroder , Sebastian Paeckel

The measurement of a quantum state poses a unique challenge for experimentalists. Recently, the technique of "direct measurement" was proposed for characterizing a quantum state in-situ through sequential weak and strong measurements. While…

As one of the main pillars of quantum technologies, quantum metrology aims to improve measurement precision using techniques from quantum information. The two main strategies to achieve this are the preparation of nonclassical states and…

Quantum Physics · Physics 2025-09-16 Matteo Fadel , Noah Roux , Manuel Gessner

A new approach to the problem of measurement in quantum mechanics is proposed. In this approach, the process of measurement is described in the Heisenberg picture and divided into two stages. The first stage is to transduce the measured…

Quantum Physics · Physics 2007-05-23 Masanao Ozawa

Several optomechanics experiments are now entering the highly sought nonlinear regime where optomechanical interactions are large even for low light levels. Within this regime, new quantum phenomena and improved performance may be achieved,…

Quantum Physics · Physics 2023-08-04 Jack Clarke , Pascal Neveu , Kiran E. Khosla , Ewold Verhagen , Michael R. Vanner

We present an experimental optical implementation of a parallel-in-time discrete model of quantum evolution, based on the entanglement between the quantum system and a finite dimensional quantum clock. The setup is based on a programmable…

The quantum dynamics of optomechanical systems was mostly studied for their fluctuations around classical steady states. We present a theoretical approach to determining the system observables of optomechanical systems as genuine quantum…

Quantum Physics · Physics 2012-06-21 Bing He

The quantum measurement process by a single-electron transistor or a quantum point contact coupled to a quantum bit is studied. We find a unified description of the statistics of the monitored quantity, the current, in the regime of strong…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Yuriy Makhlin , Gerd Schoen , Alexander Shnirman

We introduce a type of measurements that generalize the so-called "partial measurements" performed in recent years with phase qubits. While in the case of partial measurements it has been demonstrated that one could undo the effect of the…

Quantum Physics · Physics 2011-06-06 G. S. Paraoanu

We discuss what can be inferred from measurements on one- and two-qubit systems using a single measurement basis at various times. We show that, given reasonable physical assumptions, carrying out such measurements at quarter-period…

Quantum Physics · Physics 2010-08-23 Bella Schelpe , Adrian Kent , William Munro , Tim Spiller

Quantum metrology utilizes entanglement for improving the sensitivity of measurements. Up to now the focus has been on the measurement of just one out of two non-commuting observables. Here we demonstrate a laser interferometer that…

Quantum entanglement of mechanical systems emerges when distinct objects move with such a high degree of correlation that they can no longer be described separately. Although quantum mechanics presumably applies to objects of all sizes,…