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Classical shallow networks are universal approximators. Given a sufficient number of neurons, they can reproduce any continuous function to arbitrary precision, with a resource cost that scales linearly in both the input size and the number…

The characterization of a unitary gate is experimentally accomplished via Quantum Process Tomography, which combines the outcomes of different projective measurements to reconstruct the underlying operator. The process matrix is typically…

Quantum Physics · Physics 2025-09-17 Tareq Jaouni , Francesco Di Colandrea , Lorenzo Amato , Filippo Cardano , Ebrahim Karimi

We establish a formal bridge between qubit-based and photonic quantum computing. We do this by defining a functor from the ZX calculus to linear optical circuits. In the process we provide a compositional theory of quantum linear optics…

Quantum Physics · Physics 2023-11-16 Giovanni de Felice , Bob Coecke

We describe an optical scheme for optimal Gaussian n to m cloning of coherent states. The scheme, which generalizes a recently demonstrated scheme for 1 to 2 cloning, involves only linear optical components and homodyne detection.

Quantum Physics · Physics 2009-11-13 Stefano Olivares , Matteo G. A. Paris , Ulrik L. Andersen

The quantum approximate optimization algorithm (QAOA) transforms a simple many-qubit wavefunction into one which encodes a solution to a difficult classical optimization problem. It does this by optimizing the schedule according to which…

Quantum Physics · Physics 2022-06-29 Yunlong Yu , Chenfeng Cao , Carter Dewey , Xiang-Bin Wang , Nic Shannon , Robert Joynt

Predicting phenomena that mix few-photon quantum optics with strong field nonlinear optics is hindered by the use of separate theoretical formalisms for each regime. We close this gap with a unified effective field theory valid for…

Optics · Physics 2025-12-30 Xiaochen Liu , Ken-Tye Yong

Recent reports of large photonic nonlinearities in integrated photonic devices, using the strong excitonic light-matter coupling in semiconductors, necessitate a tailored design framework for quantum processing in the limit of low photon…

Quantum Physics · Physics 2026-05-14 Mathias Van Regemortel , Thomas Van Vaerenbergh

We present a numerical method for the accurate and efficient simulation of strongly localized light sources, such as quantum dots, embedded in dielectric micro-optical structures. We apply the method in order to optimize the photon…

We introduce a framework for simulating quantum optics by decomposing the system into a finite rank (number of terms) superposition of coherent states. This allows us to define a resource theory, where linear optical operations are 'free'…

Quantum Physics · Physics 2023-12-19 Jeffrey Marshall , Namit Anand

Electron transport in realistic physical and chemical systems often involves the non-trivial exchange of energy with a large environment, requiring the definition and treatment of open quantum systems. Because the time evolution of an open…

In its most basic form, the finite quantum de Finetti theorem states that the reduced k-partite density operator of an n-partite symmetric state can be approximated by a convex combination of k-fold product states. Variations of this result…

Quantum Physics · Physics 2009-01-12 Robert Koenig , Graeme Mitchison

We analyze the fundamental quantum limit of the resolution of an optical imaging system from the perspective of the detection problem of deciding whether the optical field in the image plane is generated by one incoherent on-axis source…

Quantum Physics · Physics 2018-12-10 Xiao-Ming Lu , Hari Krovi , Ranjith Nair , Saikat Guha , Jeffrey H. Shapiro

One of the greatest difficulties in the applications of single photon polarization states as qubits is the realization of controlled interactions between two photons. Recently, it has been shown that such interactions can be realized using…

Quantum Physics · Physics 2007-05-23 Holger F. Hofmann , Shigeki Takeuchi

Highly coherent optical sources are a key element in several fields of physics, in particular in time frequency metrology. Over the past decennia, there has been particular efforts in developing such sources to the expense of sophisticated…

Optics · Physics 2021-08-10 Mehdi Alouini , Gwennael Danion , Marc Vallet

Practical quantum state tomography is usually performed by carrying out repeated measurements on many copies of a given state. The accuracy of the reconstruction depends strongly on the dimensionality of the system and the number of copies…

Quantum Physics · Physics 2008-07-08 Alex Ling , Antia Lamas-Linares , Christian Kurtsiefer

Based on recently introduced efficient quantum state tomography schemes, we propose a scalable method for the tomography of unitary processes and the reconstruction of one-dimensional local Hamiltonians. As opposed to the exponential…

Quantum Physics · Physics 2015-04-30 M. Holzäpfel , T. Baumgratz , M. Cramer , M. B. Plenio

We address several estimation problems in quantum optics by means of the maximum-likelihood principle. We consider Gaussian state estimation and the determination of the coupling parameters of quadratic Hamiltonians. Moreover, we analyze…

Quantum Physics · Physics 2009-11-06 G. Mauro D'Ariano , Matteo G. A. Paris , Massimiliano F. Sacchi

We show that open quantum systems of two-level atoms symmetrically coupled to a single-mode photon field can be efficiently simulated by applying a SU(4) group theory to quantum master equations. This is important since many foundational…

Quantum Physics · Physics 2013-06-12 Minghui Xu , D. A. Tieri , M. J. Holland

We propose and analyze a nanomechanical architecture where light is used to perform linear quantum operations on a set of many vibrational modes. Suitable amplitude modulation of a single laser beam is shown to generate squeezing,…

Mesoscale and Nanoscale Physics · Physics 2012-12-17 Michael Schmidt , Max Ludwig , Florian Marquardt

Imaging in quantum optics (QO) is usually formulated in the languages of quantum mechanics and Fourier optics. While relatively advanced fields, notions such as different reference frames and the degradation of entanglement due to…

Quantum Physics · Physics 2019-12-11 Nicholas Bornman , Achim Kempf , Andrew Forbes
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