scholarly journals Scqubits: a Python package for superconducting qubits

Quantum ◽  
2021 ◽  
Vol 5 ◽  
pp. 583
Author(s):  
Peter Groszkowski ◽  
Jens Koch
Keyword(s):  
Spectral Data ◽  
Hilbert Spaces ◽  
Energy Levels ◽  
Superconducting Qubits ◽  
Energy Spectra ◽  
Matrix Elements ◽  
Computing Power ◽  
Superconducting Circuits ◽  
Multiple Cores ◽  
Python Package

scqubits is an open-source Python package for simulating and analyzing superconducting circuits. It provides convenient routines to obtain energy spectra of common superconducting qubits, such as the transmon, fluxonium, flux, cos(2ϕ) and the 0-π qubit. scqubits also features a number of options for visualizing the computed spectral data, including plots of energy levels as a function of external parameters, display of matrix elements of various operators as well as means to easily plot qubit wavefunctions. Many of these tools are not limited to single qubits, but extend to composite Hilbert spaces consisting of coupled superconducting qubits and harmonic (or weakly anharmonic) modes. The library provides an extensive suite of methods for estimating qubit coherence times due to a variety of commonly considered noise channels. While all functionality of scqubits can be accessed programatically, the package also implements GUI-like widgets that, with a few clicks can help users both create relevant Python objects, as well as explore their properties through various plots. When applicable, the library harnesses the computing power of multiple cores via multiprocessing. scqubits further exposes a direct interface to the Quantum Toolbox in Python (QuTiP) package, allowing the user to efficiently leverage QuTiP's proven capabilities for simulating time evolution.

Rotational excitations of diatomic molecule with delta potential barrier

2018 ◽  
Vol 17 (04) ◽  
pp. 1850022
Author(s):  
Sonia Lumb ◽  
Shalini Lumb ◽  
Vinod Prasad
Keyword(s):  
Diatomic Molecule ◽  
Applied Field ◽  
Morse Potential ◽  
Short Range ◽  
Delta Function ◽  
Energy Spectra ◽  
Matrix Elements ◽  
Delta Potential ◽  
Homonuclear Diatomic Molecule ◽  
Delta Functions

The interatomic interactions in a diatomic molecule can be fairly modeled by the Morse potential. Short range interactions of the molecule with the neighboring environment can be analyzed by modifying this potential by delta functions. Energy spectra and radial matrix elements have been calculated using an accurate nine-point finite-difference method for such an interacting homonuclear diatomic molecule. The effect of the strength and position of a single delta function interaction on the alignment of this molecule has been studied. The dependence of alignment on the strength of applied field has also been analyzed.

scholarly journals Large Scale Shell Model Calculations of the Negative-Parity States Structure in 24Mg Nucleus

2021 ◽  
Vol 66 (4) ◽  
pp. 293
Author(s):  
A.A. Al-Sammarraie ◽  
F.A. Ahmed ◽  
A.A. Okhunov
Keyword(s):  
Shell Model ◽  
Large Scale ◽  
Transition Probabilities ◽  
Transition Probability ◽  
Energy Levels ◽  
Form Factors ◽  
Model Space ◽  
Negative Parity ◽  
Matrix Elements ◽  
Model Calculations

The negative-parity states of 24Mg nucleus are investigated within the shell model. We are based on the calculations of energy levels, total squared form factors, and transition probability using the p-sd-pf (PSDPF) Hamiltonian in a large model space (0 + 1) hW. The comparison between the experimental and theoretical states showed a good agreement within a truncated model space. The PSDPF-based calculations successfully reproduced the data on the total squared form factors and transition probabilities of the negative-parity states in 24Mg nucleus. These quantities depend on the one-body density matrix elements that are obtained from the PSDPF Hamiltonian. The wave functions of radial one-particle matrix elements calculated with the harmonic-oscillator potential are suitable to predict experimental data by changing the center-of-mass corrections.

scholarly journals Влияние деформации на энергетический спектр и спектр оптического поглощения фуллерена C-=SUB=-20-=/SUB=- в модели Хаббарда

2019 ◽  
Vol 61 (2) ◽  
pp. 395
Author(s):  
А.В. Силантьев
Keyword(s):  
Group Theory ◽  
Hubbard Model ◽  
Symmetry Group ◽  
Energy Levels ◽  
Analytical Form ◽  
Symmetry Reduction ◽  
Energy Spectra ◽  
Symmetry Groups ◽  
Static Fluctuation Approximation ◽  
Static Fluctuation

Abstract —Anticommutator Green’s functions and energy spectra of fullerene C_20 with the I _ h , D _5 d , and D _3 d symmetry groups have been obtained in an analytical form within the Hubbard model and static fluctuation approximation. The energy states have been classified using the methods of group theory, and the allowed transitions in the energy spectra of fullerene C_20 with the I _ h , D _5 d , and D _3 d symmetry groups have been determined. It is also shown how the energy levels of fullerene C_20 with the I _ h symmetry group are split with the symmetry reduction.

Study of High-spin States for 90,91,92Y Isotopes by Using Oxbash Code

2021 ◽  
Vol 14 (1) ◽  
pp. 25-33
Keyword(s):  
Experimental Data ◽  
Transition Probabilities ◽  
Energy Levels ◽  
Model Space ◽  
Low Energy ◽  
Energy Spectra ◽  
Spin States ◽  
Nuclear Shell Model ◽  
High Spin States ◽  
Nuclear Shell

Abstract: In this paper, calculations of 90,91,92Y isotopes have been performed by application of nuclear shell model in the Gloeckner (Gl) model space for two different interactions (Gloeckner (Gl) and Gloeckner pulse bare G-Matrix (Glb) using Oxbash code. The energy levels are compared and discussed with experimental data and based on our results, many predictions about spins and parity were observed between experimental states, in addition to the predictions of low-energy spectra and B (E2; ↓) and B (M1; ↓)) transitional strengths in the isotopes 90,91,92Y. These predictions were not known in the experimental data. Keywords: Energy levels, Transition probabilities, Oxbash code.

scholarly journals Theoretical investigation of energy levels and transition data for S II, Cl III, Ar IV

2019 ◽  
Vol 623 ◽  
pp. A155 ◽  
Author(s):  
P. Rynkun ◽  
G. Gaigalas ◽  
P. Jönsson
Keyword(s):  
Energy Levels ◽  
Electric Quadrupole ◽  
General Purpose ◽  
Energy Spectra ◽  
Astrophysical Plasmas ◽  
Internal Validation ◽  
Hartree Fock ◽  
Self Energy ◽  
Relativistic Configuration ◽  
Relativistic Configuration Interaction

Aims. The aim of this work is to present accurate and extensive results of energy spectra and transition data for the S II, Cl III, and Ar IV ions. These data are useful for understanding and probing physical processes and conditions in various types of astrophysical plasmas.Methods. The multiconfiguration Dirac–Hartree–Fock (MCDHF) and relativistic configuration interaction (RCI) methods, which are implemented in the general-purpose relativistic atomic structure package GRASP2K, are used in the present work. In the RCI calculations the transverse-photon (Breit) interaction, the vacuum polarization, and the self-energy corrections are included.Results. Energy spectra are presented comprising the 134, 87, and 103 lowest states in S II, Cl III, and Ar IV, respectively. Energy levels are in very good agreement with NIST database recommended values and associated with smaller uncertainties than energies from other theoretical computations. Electric dipole (E1), magnetic dipole (M1), and electric quadrupole (E2) transition data are computed between the above states together with the corresponding lifetimes. Based on internal validation, transition rates for the majority of the stronger transitions are estimated to have uncertainties of less than 3%.

MULTIBAND FINITE ELEMENT MODELING OF WAVEFUNCTION-ENGINEERED ELECTRO-OPTICAL DEVICES

1995 ◽  
Vol 04 (01) ◽  
pp. 191-243 ◽  
Author(s):  
L. R. RAM-MOHAN ◽  
J. R. MEYER
Keyword(s):  
Finite Element ◽  
Energy Levels ◽  
Optical Devices ◽  
General Concept ◽  
Semiconductor Heterostructures ◽  
Matrix Elements ◽  
Transition Matrix Elements ◽  
Band Mixing ◽  
Degree Of Control ◽  
Structure Engineering

Recent advances in the modeling of semiconductor heterostructures with complex geometries allow one to go beyond band-structure engineering to the more general concept of wavefunction engineering. In this work, we illustrate how tailoring the band mixing and spatial distribution of the carriers leads to an expanded degree of control over such properties as the dispersion relations, interband and intersubband transition matrix elements, nonlinear optical and electro-optical coefficients, and lifetimes. The computations are based on a multiband finite element method (FEM) approach which readily yields energy levels, electron and hole wavefunctions, and optical matrix elements for heterostructures with arbitrary layer thickness, material composition, and internal strain. Application of the FEM to laterally-patterned heterostructures is also discussed.

scholarly journals Geometric Models of the Relativistic Harmonic Oscillator

1997 ◽  
Vol 12 (20) ◽  
pp. 3545-3550 ◽  
Author(s):  
Ion I. Cotăescu
Keyword(s):  
Harmonic Oscillator ◽  
Finite Number ◽  
Continuous Spectrum ◽  
Energy Levels ◽  
Nonrelativistic Limit ◽  
Energy Spectra ◽  
De Sitter ◽  
Geometric Models ◽  
Relativistic Harmonic Oscillator ◽  
Quantum Models

A family of relativistic geometric models is defined as a generalization of the actual anti-de Sitter (1 + 1) model of the relativistic harmonic oscillator. It is shown that all these models lead to the usual harmonic oscillator in the nonrelativistic limit, even though their relativistic behavior is quite different. Among quantum models we find a set of models with countable energy spectra, and another one having only a finite number of energy levels and in addition a continuous spectrum.

scholarly journals Quantum Simulations of Physics Problems

2003 ◽  
Vol 01 (02) ◽  
pp. 189-206 ◽  
Author(s):  
Rolando Somma ◽  
Gerardo Ortiz ◽  
Emanuel Knill ◽  
James Gubernatis
Keyword(s):  
Physical Properties ◽  
Hilbert Spaces ◽  
Correlation Functions ◽  
Physical System ◽  
Quantum Computer ◽  
Energy Spectra ◽  
Quantum Networks ◽  
Quantum Simulations ◽  
Physical Problems ◽  
Large Quantum

If a large Quantum Computer (QC) existed today, what type of physical problems could we efficiently simulate on it that we could not efficiently simulate on a classical Turing machine? In this paper we argue that a QC could solve some relevant physical "questions" more efficiently. The existence of one-to-one mappings between different algebras of observables or between different Hilbert spaces allow us to represent and imitate any physical system by any other one (e.g. a bosonic system by a spin-1/2 system). We explain how these mappings can be performed, and we show quantum networks useful for the efficient evaluation of some physical properties, such as correlation functions and energy spectra.

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