HQS Spin Mapper

Extracting Spin Physics of Electronic Systems

Model Analysis

HQStage Module

From chemical reactions to magnetic materials, the presence of unpaired electrons holds immense significance in shaping various material properties. Recognizing this crucial role, the HQS Spin Mapper has been created to seamlessly transfer unpaired electrons from electronic systems into a spin framework.

By facilitating the conversion of electron systems into a spin-based representation, the HQS Spin Mapper opens up a realm of possibilities for exploring the intricate world of electron interactions. It empowers researchers to explore the effects of spin-spin interactions, both in closed and open environments.

This module serves as a catalyst for identifying and extracting the fundamental spin degrees of freedom present in solids and molecules, enabling detailed simulations to unravel the quantum properties that underlie their behavior.
Describing important quantum mechanical properties of materials through spin degrees of freedom also allows a smooth connection to quantum computers.

Features

  • Spin Degree of Freedom Identification: The tool allows for the precise identification and characterization of spin degrees of freedom in solids and molecules.

  • Mapping to Spin Systems: The HQS Spin Mapper enables the mapping of identified spin degrees of freedom onto pure spin, tJ,  or spin-bath type systems via a generalized Schrieffer-Wolff transformation.

  • Besides enabling simulations for larger systems the mapping of spin systems directly reveals the character of the spin-spin interaction in the systems.

  • Efficient Research and Development: Rapid identification and mapping of spin properties allows researchers and developers to work more efficiently, gaining deeper insights into the quantum mechanical aspects of their studies.

  • Versatile Applications: HQS Spin Mapper accelerates the accurate simulation of quantum processes, enabling in-depth studies of materials for batteries and atomic-level exploration of chemical reactions. In addition, the extension to other degrees of freedom is straightforward.

Benefits

  • Simplified Modeling: The ability to map onto spin systems and to perform spin-based simulations makes modeling complex quantum mechanical systems more accessible and user-friendly.

  • The only tool that allows the application of an automated Schrieffer-Wolf transformation to mixed systems of spins and fermions.

  • The mapping to spin systems allows to extract models suitable for quantum computers directly from the full quantum chemistry description.

Use Case

  • Identification of spin like orbitals in transition metal complexes like the micro-solvated nickel (II) ion

  • Analysis of magnetic properties in materials like CrI₃

  • HQS Spin Mapper identifies radical character of molecules and provides their fine analysis invaluable for understanding chemical reactivity.

  • Compact mapping of problems from quantum chemistry to quantum computers

Related Use Case

Empfohlen
MANIQU: Efficient material simulation on NISQ quantum computers
MANIQU: Efficient material simulation on NISQ quantum computers

In collaboration with Bosch, BASF SE, Friedrich-Alexander-Universität Erlangen, and Heinrich-Heine-Universität Düsseldorf, HQS leads the MANIQU project. Focused on quantum material simulations, HQS introduces the HQS Spin Mapper for transition metal-containing materials. Addressing challenges in simulating strongly correlated electron systems, the project explores NISQ devices' accuracy for material properties. HQS's hybrid algorithms, integrated into the Noise App, enable real-time quantum simulations, a breakthrough for properties beyond the ground state. The Spin Mapper facilitates electronic system simulation on NISQ devices through spin interactions, uncovering unexplored possibilities. Additionally, the enhanced Qolossal tool offers precise simulations of large material sections, incorporating temperature, topological effects, and more. HQS's role in workflow integration ensures a commercially usable application, accessible remotely via a cloud-based platform. This collaboration pioneers quantum-driven innovations for future markets.

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Theoretical Background

Empfohlen
White Paper: A method to derive material-specific spin-bath model descriptions of materials displaying prevalent spin physics (for simulation on NISQ devices)
White Paper: A method to derive material-specific spin-bath model descriptions of materials displaying prevalent spin physics (for simulation on NISQ devices)

Authors: Benedikt M. Schoenauer, Nicklas Enenkel, Florian G. Eich, Michael Marthaler, Sebastian Zanker, and Peter Schmitteckert

Magnetism and spin physics are true quantum mechanical effects and their description usually requires multi reference methods and is often hidden in the standard description of molecules in quantum chemistry. In this work we present a twofold approach to the description of spin physics in molecules and solids. First, we present a method that identifies the single-particle basis in which a given subset of the orbitals is equivalent to spin degrees of freedom for models and materials which feature significant spin physics at low energies. We introduce a metric for the spin-like character of a basis orbital, of which the optimization yields the basis containing the optimum spin-like basis orbitals. Second, we demonstrate an extended Schrieffer-Wolff transformation method to derive the effective Hamiltonian acting on the subspace of the Hilbert space in which the charge degree of freedom of electron densities in the spin-like orbitals is integrated out. The method then yields an effective spin-bath Hamiltonian description for the system. This extended Schrieffer-Wolff transformation is applicable to a wide range of Hamiltonians and has been utilized in this work for model Hamiltonians as well as the active space Hamiltonian of molecular chromium bromide.

Efficient Random Phase Approximation for Diradicals
Efficient Random Phase Approximation for Diradicals

Authors: Reza G. Shirazi, Vladimir V. Rybkin, Michael Marthaler, and Dmitry S. Golubev

We apply the analytically solvable model of two electrons in two orbitals to diradical molecules, characterized by two unpaired electrons. The effect of the doubly occupied and empty orbitals is taken into account by means of random phase approximation (RPA). We show that in the static limit the direct RPA leads to the renormalization of the parameters of the two-orbital model. We test our model by comparing its predictions for the singlet-triplet splitting with results from multi-reference CASSCF and NEVPT2 simulations for a set of ten molecules. We find that, for the whole set, the average relative difference between the singlet-triplet gaps predicted by the RPA-corrected two-orbital model and by NEVPT2 is about 40%. For the five molecules with the smallest singlet-triplet splitting the accuracy is better than 20%.

Understanding Radicals via Orbital Parities
Understanding Radicals via Orbital Parities

Authors: Reza G. Shirazi, Benedikt M. Schoenauer, Peter Schmitteckert, Michael Marthaler, and Vladimir V. Rybkin

We introduce analysis of orbital parities as a concept and a tool for understanding radicals. Based on fundamental reduced one- and two-electron density matrices, our approach allows us to evaluate a total measure of radical character and provides spin-like orbitals to visualize real excess spin or odd electron distribution of singlet polyradicals. Finding spin-like orbitals aumotically results in their localization in the case of disjoint (zwitterionic) radicals and so enables radical classification based on spin-site separability. We demonstrate capabilities of the parity analysis by applying it to a number of polyradicals and to prototypical covalent bond breaking.

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