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We will show how to measure the overlap between photon polarization states with the use of linear optics and postselection only. Our scheme is based on quantum teleportation and succeeds with the probability of 1/8.

Quantum Physics · Physics 2007-05-23 Andrzej Grudka , Antoni Wojcik

State of a $d$-dimensional quantum system can only be inferred by performing an informationally complete measurement with $m\geqslant d^2$ outcomes. However, an experimentally accessible measurement can be informationally incomplete. Here…

Quantum Physics · Physics 2021-01-18 V. A. Zhuravlev , S. N. Filippov

We measure many-body interactions in isolated quantum dot states using double-quantum multidimensional coherent spectroscopy. Few states are probed in a diffraction limited spot, which is enabled by a novel collinear scheme in which…

Mesoscale and Nanoscale Physics · Physics 2018-02-21 Eric W. Martin , Steven T. Cundiff

Quantum Schrodinger cat states are of great interest in quantum communications and quantum optics. These states are used in various scientific fields such as quantum computing, quantum error correction and high-precision measurements. The…

Quantum Physics · Physics 2022-01-12 D. V. Fastovets , Yu. I. Bogdanov , N. A. Bogdanova , V. F. Lukichev

Quantum metrology overcomes standard precision limits by exploiting collective quantum superpositions of physical systems used for sensing, with the prominent example of non-classical multiphoton states improving interferometric techniques.…

A general law is presented for (composite) quantum systems which directly describes the time evolution of quantum states (with one or both components) through an arbitrary noisy quantum channel. It is shown that the time evolution of all…

Quantum Physics · Physics 2009-06-21 Chang-shui Yu , He-shan Song

The problem of estimating a generic phase-shift experienced by a quantum state is addressed for a generally degenerate phase shift operator. The optimal positive operator-valued measure is derived along with the optimal input state. Two…

Quantum Physics · Physics 2009-10-31 G. M. D'Ariano , C. Macchiavello , M. F. Sacchi

The paradigm of quantum metrology and sensing aims to identify a quantum advantage in precision at a fixed energy of the probe state. However, in practice, employing high-energy classical probes is often simpler than leveraging the quantum…

Quantum Physics · Physics 2026-02-12 Giuseppe Ortolano , Ivano Ruo-Berchera , Leonardo Banchi

We present an improved phase estimation scheme employing entangled coherent states and demon- strate that the states give the smallest variance in the phase parameter in comparison to NOON, BAT and "optimal" states under perfect and lossy…

Quantum Physics · Physics 2011-11-30 Jaewoo Joo , William J. Munro , Timothy P. Spiller

A new method of quantum state tomography for quantum information processing is described. The method based on two-dimensional Fourier transform technique involves detection of all the off-diagonal elements of the density matrix in a…

Quantum Physics · Physics 2009-11-07 Ranabir Das , T. S. Mahesh , Anil Kumar

Suppose you receive a sequence of qubits where each qubit is guaranteed to be in one of two pure states, but you do not know what those states are. Your task is to determine the states. This can be viewed as a kind of quantum state learning…

Entanglement represents an important resource for quantum information processing, but its generation itself requires physical resources that are limited. We propose a scheme for generating a wide class of entangled qudit-type states of…

Quantum Physics · Physics 2012-02-09 S. Ya. Kilin , A. B. Mikhalychev

We propose a method for detecting bipartite entanglement in a many-body mixed state based on estimating moments of the partially transposed density matrix. The estimates are obtained by performing local random measurements on the state,…

Quantum interference is a central resource in many quantum-enhanced tasks, from computation to communication protocols. While it usually occurs between identical input photons, quantum interference can be enabled by projecting the quantum…

The form of the eigenstates of an atom coupled to a cavity mode displaying a three dimensional periodic profile are obtained. It is shown that the quantized motion leads to degenerate states where the atomic degrees of freedom are masked,…

Quantum Physics · Physics 2020-02-19 R. Gutiérrez-Jáuregui

The many-body state of carriers confined in a quantum dot is controlled by the balance between their kinetic energy and their Coulomb correlation. In coupled quantum dots, both can be tuned by varying the inter-dot tunneling and…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Massimo Rontani , Filippo Troiani , Ulrich Hohenester , Elisa Molinari

Strong-field quantum-state control is investigated, taking advantage of the full---amplitude and phase---characterization of the interaction between matter and intense ultrashort pulses via transient-absorption spectroscopy. A sequence of…

Atomic Physics · Physics 2017-04-26 Stefano M. Cavaletto , Zoltán Harman , Thomas Pfeifer , Christoph H. Keitel

Despite their inextricable quantum mechanical nature, events at a high energy particle collider experiment typically have very few unambiguous quantum signatures, due the type of data and the manner in which they are collected. We present a…

High Energy Physics - Phenomenology · Physics 2022-05-25 Andrew J. Larkoski

By projecting onto complex optical mode profiles, it is possible to estimate arbitrarily small separations between objects with quantum-limited precision, free of uncertainty arising from overlapping intensity profiles. Here we extend these…

We explore the quantum transmission through open oval shaped quantum dots. The transmission spectra show periodic resonances and, depending on the geometry parameter, a strong suppression of the transmission for low energies. Applying a…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 D. Buchholz , P. Drouvelis , P. Schmelcher