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We introduce the quantum stochastic differential equation (QSDE) approach to exactly analyze of the response of quantum systems to a continuous-mode two-photon input. The QSDE description of the two-photon process allows us to integrate the…

Quantum Physics · Physics 2016-03-07 Yu Pan , Daoyi Dong , Guofeng Zhang

In 1949, Ramsey's method of separated oscillating fields was elaborated boosting over many decades metrological performances of atomic clocks and becoming the standard technique for very high precision spectroscopic measurements. A…

Atomic Physics · Physics 2022-05-17 T. Zanon-Willette , D. Wilkowski , R. Lefevre , A. V. Taichenachev , V. I. Yudin

The quantum master equation (QME), used to describe the Markov process of interaction between atoms and field, has a number of significant drawbacks. It is extremely memory intensive, and also inapplicable to the case of long-term memory in…

Quantum Physics · Physics 2024-10-29 Yuri Ozhigov , You Jiangchuan

We propose an approach to measure the quantum phase of an electron in a non-Abelian system using the algorithm of Quantum Phase Estimation (QPE). The discrete-path systems were previously studied in the context of square or rectangular…

Quantum Physics · Physics 2025-09-15 Seng Ghee Tan , Son-Hsien Chen , Ying-Cheng Yang , Yen-Fu Chen , Yen-Lin Chen , Chia-Hsiu Hsieh

We calculate the non-forward quark matrix elements of operators with two covariant derivatives needed for the renormalisation of the second moment of generalised parton distributions in one-loop lattice perturbation theory using Wilson…

High Energy Physics - Lattice · Physics 2008-11-26 M. Göckeler , R. Horsley , H. Perlt , P. E. L. Rakow , A. Schäfer , G. Schierholz , A. Schiller

This work demonstrates that the Deutsch algorithm can be effectively modelled using a two-level harmonic oscillator within the second quantization formalism. By adopting this framework, evolution operators are derived. We present a…

Quantum Physics · Physics 2026-05-05 Krzysztof Lider , Marek Góźdź

We consider the problem of asymptotic reconstruction of the state and parameter values in systems of ordinary differential equations. A solution to this problem is proposed for a class of systems of which the unknowns are allowed to be…

Optimization and Control · Mathematics 2015-03-13 Ivan Y. Tyukin , Erik Steur , Henk Nijmeijer , Cees van Leeuwen

We investigate quantum phase transitions, quantum criticality, and Berry phase for the ground state of an ensemble of non-interacting two-level atoms embedded in a non-linear optical medium, coupled to a single-mode quantized…

Quantum Physics · Physics 2020-06-12 C. A. Estrada Guerra , J. Mahecha-Gómez , J. G. Hirsch

Real-time dynamics of quantum observables provide direct access to excitation spectra and correlation functions in quantum many-body systems, but currently available quantum devices are limited to short evolution times due to decoherence.…

Quantum Physics · Physics 2026-03-17 Jinyang Li , Satoshi Iso , Shunji Matsuura , Lingxiao Wang , Xiaoyang Wang

We propose an approach to measuring nonresonant coupled systems, which gives a parametrically smaller error than the conventional fast projective measurements. The approach takes into account that, due to the coupling, excitations are not…

Quantum Physics · Physics 2009-03-05 L. Fedichkin , M. Shapiro , M. I. Dykman

Experimentally engineering high-dimensional quantum states is a crucial task for several quantum information protocols. However, a high degree of precision in the characterization of experimental noisy apparatus is required to apply…

We conduct a theoretical study of the nonlinear optical response of a two-dimensional semi-conductor quantum dot supercrystal subjected to a quasi-resonant continuous wave excitation. Aconstituent quantum dot is odeled as a three-level…

We resolve the real-time electric field of a femtosecond third-order nonlinear optical signal in the molecular frame. The electric field emitted by the induced third-order polarization from impulsively pre-aligned gas-phase molecules at…

We present a self-consistent quantum optics approach to calculating the surface enhanced Raman spectrum of molecules coupled to arbitrarily shaped plasmonic systems. Our treatment is intuitive to use and provides fresh analytical insight…

Optics · Physics 2017-06-26 Mohsen Kamandar Dezfouli , Stephen Hughes

An analytically derived 'integral operator' approach is introduced to estimate the expectation value of a quantum operator for an evolving state weighted with an exponential function. This allows to compute quantities useful in Nuclear…

Quantum Physics · Physics 2017-05-16 Simone Sturniolo

We present the first measurement of two-mode squeezing between the twin beams produced by a doubly resonant optical parameter oscillator (OPO) in above threshold operation, based on parametric amplification by non degenerate four wave…

Quantum Physics · Physics 2020-08-26 A. Montaña Guerrero , P. Nussenzveig , M. Martinelli , A. M. Marino , H. M. Florez

While the quantum regression theorem (QRT) is the standard tool for computing multi-time correlation functions in open quantum systems, it relies on system-bath separability and an environment that remains in equilibrium, assumptions that…

Quantum Physics · Physics 2026-04-16 Matias Bundgaard-Nielsen , Jake Iles-Smith

Two-photon coherent states are one of the main building pillars of non-linear and quantum optics. It is the basis for the generation of minimum-uncertainty quantum states and entangled photon pairs, applications not obtainable from standard…

Mesoscale and Nanoscale Physics · Physics 2022-05-30 A. A. Reynoso , G. Usaj , D. L. Chafatinos , F. Mangussi , A. E. Bruchhausen , A. S. Kuznetsov , K. Biermann , P. V. Santos , A. Fainstein

We present a quantum algorithm to prepare injective PEPS on a quantum computer, a class of open tensor networks representing quantum states. The run-time of our algorithm scales polynomially with the inverse of the minimum condition number…

Quantum Physics · Physics 2015-03-19 Martin Schwarz , Kristan Temme , Frank Verstraete

The recently developed Projective Quantum Eigensolver (PQE) has been demonstrated as an elegant methodology to compute the ground state energy of molecular systems in Noisy Intermdiate Scale Quantum (NISQ) devices. The iterative…

Quantum Physics · Physics 2023-03-21 Sonaldeep Halder , Chayan Patra , Dibyendu Mondal , Rahul Maitra