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Quantum Kernel Estimation (QKE) is a technique based on leveraging a quantum computer to estimate a kernel function that is classically difficult to calculate, which is then used by a classical computer for training a Support Vector Machine…

Quantum Physics · Physics 2023-08-01 Marco Russo , Edoardo Giusto , Bartolomeo Montrucchio

We present a formalism that explicitly unifies the commonly used Nakajima-Zwanzig approach for reduced density matrix dynamics with the more versatile Mori theory in the context of nonequilibrium dynamics. Employing a Dyson-type expansion…

Chemical Physics · Physics 2016-05-25 Andrés Montoya-Castillo , David. R. Reichman

Simulating molecular systems on quantum computers requires efficient mappings from Fermionic operators to qubit operators. Traditional mappings such as Jordan-Wigner or Bravyi-Kitaev often produce high-weight Pauli terms, increasing circuit…

Quantum Physics · Physics 2025-11-13 James Brown , Tarini S Hardikar , Kenny Heitritter , Kanav Setia

The hierarchical quantum master equation (HQME) approach is an accurate method to describe quantum transport in interacting nanosystems. It generalizes perturbative master equation approaches by including higher-order contributions as well…

Mesoscale and Nanoscale Physics · Physics 2018-08-29 Andre Erpenbeck , Christian Hertlein , Christian Schinabeck , Michael Thoss

Accurate uncertainty quantification is a critical challenge in machine learning. While neural networks are highly versatile and capable of learning complex patterns, they often lack interpretability due to their ``black box'' nature. On the…

Machine Learning · Computer Science 2025-11-18 Pragatheeswaran Vipulananthan , Kamal Premaratne , Dilip Sarkar , Manohar N. Murthi

The emergence of Quantum Machine Learning (QML) to enhance traditional classical learning methods has seen various limitations to its realisation. There is therefore an imperative to develop quantum models with unique model hypotheses to…

Quantum Physics · Physics 2023-02-21 Maiyuren Srikumar , Charles D. Hill , Lloyd C. L. Hollenberg

In addition to the well-known Landauer-Buttiker scattering theory and the nonequilibrium Green's function technique for mesoscopic transports, an alternative (and very useful) scheme is quantum master equation approach. In this article, we…

Quantum Physics · Physics 2016-07-04 Xin-Qi Li

We investigate detailed balance for a quantum system interacting with thermal radiation within mixed quantum-classical theory. For a two-level system coupled to classical radiation fields, three semiclassical methods are benchmarked: (1)…

Chemical Physics · Physics 2019-07-17 Hsing-Ta Chen , Tao E. Li , Abraham Nitzan , Joseph E. Subotnik

Quantum embedding is a fundamental prerequisite for applying quantum machine learning techniques to classical data, and has substantial impacts on performance outcomes. In this study, we present Neural Quantum Embedding (NQE), a method that…

Quantum Physics · Physics 2024-08-12 Tak Hur , Israel F. Araujo , Daniel K. Park

Quantum-enhanced machine learning is a rapidly evolving field that aims to leverage the unique properties of quantum mechanics to enhance classical machine learning. However, the practical applicability of these methods remains an open…

Quantum Physics · Physics 2025-02-18 Diego Alvarez-Estevez

Quantum kernel methods are a promising method in quantum machine learning thanks to the guarantees connected to them. Their accessibility for analytic considerations also opens up the possibility of prescreening datasets based on their…

Quantum Physics · Physics 2024-08-05 Sebastian Egginger , Alona Sakhnenko , Jeanette Miriam Lorenz

We discuss methods for numerically solving the generalized Master equation GME which governs the time-evolution of the reduced density matrix of a mechanically movable mesoscopic device in a dissipative environment. As a specific example,…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Antti-Pekka Jauho , Tomas Novotny , Andrea Donarini , Christian Flindt

We derive an exact master equation that captures the dynamics of a quadratic quantum system linearly coupled to a Gaussian environment of the same statistics: the Gaussian Master Equation (GME). Unlike previous approaches, our formulation…

Quantum Physics · Physics 2026-01-21 Antonio D'Abbruzzo , Vittorio Giovannetti , Vasco Cavina

We propose a trajectory-based method for simulating nonadiabatic dynamics in molecular systems with two coupled electronic states. Employing a quantum-mechanically exact mapping of the two-level problem to a spin-1/2 coherent state, we…

Chemical Physics · Physics 2020-03-03 Johan E. Runeson , Jeremy O. Richardson

Quantum Boltzmann machines (QBMs) are machine-learning models for both classical and quantum data. We give an operational definition of QBM learning in terms of the difference in expectation values between the model and target, taking into…

Quantum Physics · Physics 2025-02-13 Luuk Coopmans , Marcello Benedetti

Following Ehrenfest's approach, the problem of quantum-classical correspondence can be treated in the class of trajectory-coherent functions that approximate as $\h\to 0$ a quantum-mechanical state. This idea leads to a family of systems of…

Mathematical Physics · Physics 2007-05-23 V. V. Belov , M. F. Kondratieva , A. Yu. Trifonov

Trajectories are a central concept in our understanding of classical phenomena and also in rationalizing quantum mechanical effects. In this work we provide a way to determine semiclassical paths, approximations to quantum averages in phase…

Quantum Physics · Physics 2015-06-15 Rafael Liberalquino , Fernando Parisio

Determining the ground state of a many-body Hamiltonian is a central problem across physics, chemistry, and combinatorial optimization, yet it is often classically intractable due to the exponential growth of Hilbert space with system size.…

Quantum Physics · Physics 2026-02-24 Jungyun Lee , Daniel K. Park

Generalized master equations (GMEs) -- time-local but generally neither trace-preserving nor Hermiticity-preserving -- are convenient tools to compute properties of the environment of an open or continuously monitored quantum system. A…

Quantum Physics · Physics 2026-02-27 Francesco Albarelli , Marco G. Genoni

Machine learning techniques have led to broad adoption of a statistical model of computing. The statistical distributions natively available on quantum processors are a superset of those available classically. Harnessing this attribute has…