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We investigate the effect of strong electronic correlation on the massless Dirac fermion system, $\alpha$-(BEDT-TTF)$_2$I$_3$, under pressure. In this organic salt, one can control the electronic correlation by changing pressure and access…

Strongly Correlated Electrons · Physics 2020-11-09 Y. Unozawa , Y. Kawasugi , M. Suda , H. M. Yamamoto , R. Kato4 , Y. Nishio , K. Kajita , T. Morinari , N. Tajima

We provide a brief overview of approaches for calculating the density of states of quantum systems and random matrix Hamiltonians using the tools of free probability theory. For a given Hamiltonian of a quantum system or a generic random…

Quantum Physics · Physics 2025-12-04 Keun-Young Kim , Kuntal Pal

The Dirac fermion in the random chiral models is studied which includes the random gauge field model and the random hopping model. We focus on a connection between continuum and lattice models to give a clear perspective for the random…

Mesoscale and Nanoscale Physics · Physics 2008-11-26 Shinsei Ryu , Yasuhiro Hatsugai

The equation of state of Hamiltonian lattice QCD at finite density is examined in the strong coupling limit by constructing a solution to the equation of motion corresponding to an effective Hamiltonian describing the ground state of the…

High Energy Physics - Phenomenology · Physics 2009-11-07 Yasuo Umino

We discuss a new numerical method for the determination of excited states of a quantum system using a generalization of the Feynman-Kac formula. The method relies on introducing an ensemble of non-interacting identical systems with a…

High Energy Physics - Lattice · Physics 2008-11-26 Z. Burda , Pawel Sawicki

We develop a general theory of frustration-free free-fermion systems and derive the necessary and sufficient conditions for such Hamiltonians. Assuming locality and translation invariance, we find that any band touching between the valence…

Strongly Correlated Electrons · Physics 2026-01-13 Seishiro Ono , Rintaro Masaoka , Haruki Watanabe , Hoi Chun Po

We study the effects of acceleration on fermionic Gaussian states of localized modes of a Dirac field. We consider two wave-packets in a Gaussian state and transform these to an accelerated frame of reference. In particular, we formulate…

Quantum Physics · Physics 2017-05-12 Benedikt Richter , Krzysztof Lorek , Andrzej Dragan , Yasser Omar

A wave function exposed to measurements undergoes pure state dynamics, with deterministic unitary and probabilistic measurement induced state updates, defining a quantum trajectory. For many-particle systems, the competition of these…

Statistical Mechanics · Physics 2021-11-02 M. Buchhold , Y. Minoguchi , A. Altland , S. Diehl

The rate of complexification of a quantum state is conjectured to be bounded from above by the average energy of the state. A different conjecture relates the complexity of a holographic CFT state to the on-shell gravitational action of a…

High Energy Physics - Theory · Physics 2018-03-09 Mudassir Moosa

A detailed study of orbital and radial excited states in D, Ds, B and B_s systems is performed. The chiral quark model provides the framework for the calculation of pseudoscalar meson (pi, K, ...) hadronic transitions among heavy-light…

High Energy Physics - Phenomenology · Physics 2009-11-07 Massimo Di Pierro , Estia Eichten

We study general entanglement properties of the excited states of the one dimensional translational invariant free fermions and coupled harmonic oscillators. In particular, using the integrals of motion, we prove that these Hamiltonians…

Strongly Correlated Electrons · Physics 2019-11-13 Arash Jafarizadeh , M. A. Rajabpour

How much information a fermionic state contains? To address this fundamental question, we define the complexity of a particle-conserving many-fermion state as the entropy of its Fock space probability distribution, minimized over all Fock…

Quantum Physics · Physics 2024-03-06 Tuomas I. Vanhala , Teemu Ojanen

We present an extension of the Evolving density matrices on Qubits (E$\rho$OQ) framework that enables efficient fault-tolerant preparation of fermionic quantum states. The original method circumvents state preparation by stochastic…

Quantum Physics · Physics 2026-03-25 Erik J. Gustafson , Henry Lamm

We investigate a large-$N$ CFT in a high-energy pure state coupled to a small auxiliary system of $M$ weakly-interacting degrees of freedom, and argue the relative state complexity of the auxiliary system is holographically dual to an…

High Energy Physics - Theory · Physics 2020-07-28 Alexander Yosifov , Aditya Iyer , Lachezar Filipov

We consider the Bose-Hubbard model in two and three spatial dimensions and numerically compute the quantum circuit complexity of the ground state in the Mott insulator and superfluid phases using a mean field approximation with additional…

Quantum Physics · Physics 2022-04-20 Uday Sood , Martin Kruczenski

We study the complexity for an open quantum system. Our system is a harmonic oscillator coupled to a one-dimensional massless scalar field, which acts as the bath. Specifically, we consider the reduced density matrix by tracing out the bath…

High Energy Physics - Theory · Physics 2022-02-17 Arpan Bhattacharyya , Tanvir Hanif , S. Shajidul Haque , Md. Khaledur Rahman

We consider the scaling behavior of circuit complexity under quantum quench in an a relativistic fermion field theory on a one dimensional spatial lattice. This is done by finding an exactly solvable quench protocol which asymptotes to…

High Energy Physics - Theory · Physics 2020-06-15 Sinong Liu

It has been suggested that the density of states approach to performing lattice simulations in QCD with nonzero chemical potential can be modified to improve the signal to noise ratio by performing a cumulant expansion of the complex phase…

High Energy Physics - Lattice · Physics 2013-11-20 Jeff Greensite , Joyce C. Myers , K. Splittorff

We study the temporal evolution of the circuit complexity for a subsystem in harmonic lattices after a global quantum quench of the mass parameter, choosing the initial reduced density matrix as the reference state. Upper and lower bounds…

High Energy Physics - Theory · Physics 2021-05-13 Giuseppe Di Giulio , Erik Tonni

We study the relative entropy, in the sense of Araki, for the representation of a self-dual CAR algebra $\mathfrak{A}_{SDC}(\mathcal{H},\Gamma)$. We notice, for a specific choice of $f \in \mathcal{H}$, that the associated element in…

Mathematical Physics · Physics 2022-10-20 Stefano Galanda