New carbon-based superconductors are synthesized by intercalating metal atoms into the solid-phase hydrocarbons picene and coronene. The highest reported superconducting transition temperature, Tc, of a hydrocarbon superconductor is 18 K for K3picene. physics chemistry extensively described Axpicene (A: alkali earth-metal atoms) x = 0–5. theoretical picture their electronic structure also reviewed. Future prospects discussed from viewpoint combining electronics with condensed-matter physics:...

We derive effective Hubbard-type Hamiltonians of $\kappa$-(ET)$_2X$, using an {\em ab initio} downfolding technique, for the first time organic conductors. They contain dispersions highest occupied Wannier-type molecular orbitals with nearest neighbor transfer $t$$\sim$0.067 eV a metal $X$=Cu(NCS)$_2$ and 0.055 Mott insulator $X$=Cu$_2$(CN)$_3$, as well screened Coulomb interactions. It shows unexpected differences from conventional extended H\"uckel results, especially much stronger onsite...

We report the anomalous phase evolution in ferroelectric single crystals Ba1-xCaxTiO3 (0.02<x<0.34), and demonstrate significant effects of quantum fluctuation on transition. In addition, large electromechanical responses this class are also demonstrated. Our results indicate that an effective approach to control ferroelectricity perovskite oxide can be realized not only by covalency between A site atom oxygen but substitution with small ions off-centering nature. Theoretical calculations...

RESPACK is a first-principles calculation software for evaluating the interaction parameters of materials and able to calculate maximally localized Wannier functions, response functions based on random phase approximation related optical properties, frequency-dependent electronic parameters. receives its input data from band-calculation code using norm-conserving pseudopotentials with plane-wave basis sets. Automatic generation scripts that convert band-structure results inputs are prepared...

The imaginary-time evolution method is widely known to be efficient for obtaining the ground state in quantum many-body problems on a classical computer. A recently proposed (QITE) faces of deep circuit depth and difficulty implementation noisy intermediate-scale (NISQ) devices. In this study, nonlocal approximation developed tackle difficulty. We found that by removing locality condition or local (LA), which was imposed when operator converted unitary operator, significantly reduced....

Imaginary-time evolution (ITE) on a quantum computer is promising formalism for obtaining the ground state of system. The probabilistic ITE (PITE) exploits measurements to implement nonunitary operations, and it can avoid restriction dynamics low-dimensional subspace imposed by variational parameters unlike other types ITE. In this paper, we propose PITE approach that uses only one ancillary qubit. Unlike existing approaches, proposed here constructs, under practical approximation, circuit...

To explore the electronic structure of first aromatic superconductor, potassium-doped solid picene which has been recently discovered by Mitsuhashi et al with transition temperatures $T_c=7 - 20$ K, we have obtained a first-principles as step toward elucidation mechanism superconductivity. The undoped crystal is found to four conduction bands, are characterized in terms maximally localized Wannier orbitals. We revealed how band reflects stacked arrangement molecular orbitals for both and...

We have experimentally revealed the band structure and surface Brillouin zone of insulating picene single crystals (SCs), mother organic system for a recently discovered aromatic superconductor, with ultraviolet photoelectron spectroscopy (UPS) low-energy electron diffraction laser photoconduction. A hole effective mass 2.24 m_0 mobility mu_h >= 9.0 cm^2/Vs (298 K) were deduced in Gamma-Y direction. further shown that some SCs did not show charging during UPS even without laser, which...

We theoretically explore the crystal structures of K${}_{x}$picene for which a new aromatic superconductivity has recently been discovered $x=3$, by systematically performing first-principles full structural optimization covering concentration range $x=1$--4. The symmetry (space group) pristine picene is shown to be preserved in all optimized despite significant deformations each molecule and vast rearrangements herringbone array molecules. For ($x=1$--4), indicates that (i) multiple exist...

We propose a scheme for the construction of one-particle Green's function (GF) an interacting electronic system via statistical sampling on quantum computer. Although nonunitarity creation and annihilation operators spin orbitals prevents us from preparing specific states selectively, probabilistic state preparation is demonstrated to be possible qubits. provide circuits equipped with at most two ancillary qubits obtaining all components GF. perform simulations such GFs LiH...

Abstract This study proposes a nonvariational scheme for geometry optimization of molecules the first-quantized eigensolver, which is recently proposed framework quantum chemistry using probabilistic imaginary-time evolution (PITE). In this scheme, nuclei in molecule are treated as classical point charges while electrons mechanical particles. The electronic states and candidate geometries encoded superposition many-qubit states, histogram created from repeated measurements gives global...

Quantum state preparation is a fundamental building block for various problems on quantum computer. A nonunitary operator typically designed to decay unwanted states contained in an initial using ancilla qubits and probabilistically action. In this Letter, we clarify that probabilistic nature drag advantages: The algorithms do not accelerate the computational process compared classical ones. Combining amplitude amplification (QAA) with multistep proposed address drawback, achieving quadratic...

We have obtained the first-principles electronic structure of solid coronene, which has been recently discovered to exhibit superconductivity with potassium doping. Since along picene, first aromatic superconductor, now provide a class superconductors as solids compounds, here we compare two cases in examining structures. In undoped coronene crystal, where molecules are arranged herringbone unit cell, conduction band above an insulating gap is found comprise four bands, basically originate...

Ground-state preparation is an important task in quantum computation. The probabilistic imaginary-time evolution (PITE) method a promising candidate for preparing the ground state of Hamiltonian, which comprises single ancilla qubit and forward- backward-controlled real-time operators. challenging even computation, classified as complexity-class Merlin-Arthur. However, optimal parameters PITE could potentially enhance computational efficiency to certain degree. In this paper, we analyze...

We propose an adiabatic time evolution (ATE) method for obtaining the ground state of a quantum many-electron system on circuit based first quantization. As striking feature ATE method, it consists only unitary operations representing real-time evolution, which means that does not require any ancillary qubits, nor controlled operators. Especially, we explored first-quantized formalism in this study since implementation circuits is known to be efficient. However, when realizing...

We propose an annealing scheme usable on modern Ising machines for crystal structures prediction (CSP) by taking into account the general <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mi>n</a:mi></a:math>-body atomic interactions and in particular three-body which are necessary to simulate covalent bonds. The structure is represented discretizing a unit cell placing binary variables express existence or nonexistence of atom every grid point. resulting quadratic unconstrained...

Abstract First-quantized eigensolver (FQE) is a recently proposed quantum computation framework for obtaining the ground state of an interacting electronic system based on probabilistic imaginary-time evolution. Here, we propose method introducing uniform magnetic field to FQE calculation. Our resource estimation demonstrates that additional circuit responsible can be implemented with linear depth in terms number qubits assigned each electron. Hence, introduction has no impact leading order...

We have performed the first-principles electronic structure calculation for novel superconductor Ca4Al2O6Fe2As2 which has smallest a lattice parameter and largest As height from Fe plane among Fe-As superconductors. find that one of hole-like Fermi surfaces is missing around Gamma point compared to case LaFeAsO. Analysis using maximally-localized-Wannier-function technique indicates xy orbital becomes more localized as As-Fe-As angle decreases. This induces rearrangement bands, results in...

We demonstrate that the coupled-cluster singles-and-doubles Green’s function (GFCCSD) method is a powerful and prominent tool drawing electronic band structures total energies, which many theoretical techniques struggle to reproduce. have calculated single-electron energy spectra via GFCCSD for various kinds of systems, ranging from ionic covalent van der Waals, first time: one-dimensional LiH chain, C Be chain. found bandgap becomes narrower than in HF due correlation effect. also show...

We propose a scheme for the construction of charge and spin linear-response functions an interacting electronic system via quantum phase estimation statistical sampling on computer. By using unitary decomposition operators avoiding difficulty due to their non-unitarity, we provide circuits equipped with ancillae probabilistic preparation qubit states which necessary non-unitary have acted. perform simulations such response C2 N2 molecules by comparing accurate ones based full configuration...

We propose an unfolding scheme to analyze energy spectra of complex large-scale systems which are inherently double periodicity on the basis density-functional theory. Applying our method a twisted bilayer graphene (tBLG) and stack monolayer ${\mathrm{MoS}}_{2}$ (${\mathrm{MoS}}_{2}$/graphene) as examples, we first show that conventional in past using single primitive-cell representation causes serious problems analyses spectra. then introduce multispace clarify its validity. Velocity...

The Schroedinger equation for a spinless charged particle on curved surface under an electromagnetic field has been obtained by adopting proper gauge which allows the separation of on-surface and transverse dynamics. [Phys. Rev. Lett. 100 (2008) 230403] As its extension, I provide Pauli spin-1/2 confined to field. Energy spectra sphere corrugated is are given as simple applications equation. energy levels exhibit splittings due relativistic effect known Rashba effect.