HQS Quantum Libraries

Advanced Quantum Computing Tools

Quantum Computing

HQStage Module

The HQS Quantum Libraries encompass a comprehensive suite of modules tailored to advanced quantum computing tasks. These modules include alqorithms, qonvert, the noise-mapper, and the bath-mapper, serving to facilitate quantum algorithm development, compilation, noise emulation, and system-bath interaction modeling, respectively.

Optimizing Circuit Control and System Modeling

These libraries are designed to empower researchers and developers in harnessing quantum computing capabilities with precision and flexibility. They enable users to generate circuits and QuantumPrograms from input Hamiltonians, providing fine-grained control over optimizations. By selectively applying optimizations and simulating noise effects, users can explore the behavior of quantum systems under various conditions, aiding in the development of quantum algorithms and the study of open quantum systems.

Example of classifying a Hamiltonian as ferromagnetic or anti-ferromagnetic using time propagation on a noisy quantum computer.

The NMR spectrum of non-exchangeable hydrogen of cis-3-chloroacrylic acid simulated on NISQ devices. The solid orange curve depicts the results on IBM Perth, the blue dash-dotted curve is the IonQ Aria ones, and the solid black curve shows the results with exact diagonalization.

Features

  • Alqorithms is a powerful package that enables the generation of circuits from Hamiltonians. With advanced algorithms such as parity-based, spin-interaction, and spin swap algorithms, the package provides seamless circuit generation capabilities. Whether you have a pure system Hamiltonian or a system-bath Hamiltonian, our generated circuits can be executed on a quantum computer using our qoqo-backends.

  • Qonvert, the HQS compiler package, offers comprehensive functionality for circuit and QuantumProgram optimization. It decomposes circuits into a given set of gates, optimizes them for efficiency, and introduces noise to emulate the behavior of physical quantum computers.

  • The noise-mapper enables the mapping of noise in circuits to an effective open-system model for the time evolution. This allows the analysis of algorithm behavior under realistic conditions. By accurately modeling noise, the noise-mapper provides valuable insights into its impact on circuit performance. The mapping from Trotter circuit to the noisy algorithm model allows for precise analysis and optimization of algorithms.

  • The bath-mapper facilitates the representation of the coupling between spin systems or fermionic systems and environmental baths. The environmental baths can take the form of fermionic baths, bosonic baths, spin baths or baths that are described by a spectral function. The package employs a system-bath approach based on the Bloch-Redfield master equation, ensuring accurate simulations. The bath-mapper provides a way to store the coupling information and spectral function form of the Bloch-Redfield master equation as a BlochRedfieldNoiseOperator object and offers conversion capabilities between coupled system-bath Hamiltonians and BlochRedfieldNoiseOperator objects.

Use Case

This HQStage Module is particularly valuable in industries such as quantum computing research, materials science, pharmaceuticals, finance, and telecommunications, where quantum computing holds potential for solving complex optimization problems, simulating quantum systems, and enhancing computational capabilities.

Theoretical Background

Empfohlen
Demonstration of system-bath physics on gate-based quantum computer
Demonstration of system-bath physics on gate-based quantum computer

Authors: Pascal Stadler, Matteo Lodi, Andisheh Khedri, Rolando Reiner, Kirsten Bark, Nicolas Vogt, Michael Marthaler, and Juha Leppäkangas

We demonstrate algorithmic cooling on IBM-Q devices. We utilize inherent qubit noise to simulate the equilibration of an interacting spin system towards its ground state, when coupled to a dissipative auxiliary-spin bath. The steady-state correlations in the system are defined by the system Hamiltonian and are stable as long as the algorithm can be executed. In particular, we demonstrate the relaxation of system spins to ferromagnetic and antiferromagnetic ordering, controlled by the definition of the system Hamiltonian. We are able to perform simulated cooling for global systems of up to three system spins and four auxiliary spins.

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A quantum algorithm for solving open system dynamics on quantum computers using noise
A quantum algorithm for solving open system dynamics on quantum computers using noise

Authors: Juha Leppäkangas, Nicolas Vogt, Keith R. Fratus, Kirsten Bark, Jesse A. Vaitkus, Pascal Stadler, Jan-Michael Reiner, Sebastian Zanker, Michael Marthaler

In this paper, we present a quantum algorithm that uses noise as a resource. The goal of our quantum algorithm is the calculation of operator averages of an open quantum system evolving in time. Selected low-noise system qubits and noisy bath qubits represent the system and the bath of the open quantum system. All incoherent qubit noise can be mapped to bath spectral functions. The form of the spectral functions can be tuned digitally, allowing for the time evolution of a wide range of open-system models at finite temperatures. We study the feasibility of this approach with a focus on the solution of the spin-boson model and assume intrinsic qubit noise that is dominated by damping and dephasing. We find that classes of open quantum systems exist where our algorithm performs very well, even with gate errors as high as 1%. In general, the presented algorithm performs best if the system-bath interactions can be decomposed into native gates.

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Describing Trotterized Time Evolutions on Noisy Quantum Computers via Static Effective Lindbladians
Describing Trotterized Time Evolutions on Noisy Quantum Computers via Static Effective Lindbladians

Authors: Keith R. Fratus, Kirsten Bark, Nicolas Vogt, Juha Leppäkangas, Sebastian Zanker, Michael Marthaler, Jan-Michael Reiner
We consider the extent to which a noisy quantum computer is able to simulate the time evolution of a quantum spin system in a faithful manner. Given a specific set of assumptions regarding the manner in which noise acting on such a device can be modeled at the circuit level, we show how the effects of noise can be reinterpreted as a modification to the dynamics of the original system being simulated. In particular, we find that this modification corresponds to the introduction of static Lindblad noise terms, which act in addition to the original unitary dynamics. The form of these noise terms depends not only on the underlying noise processes occurring on the device but also on the original unitary dynamics, as well as the manner in which these dynamics are simulated on the device, i.e., the choice of a quantum algorithm. We call this effectively simulated open quantum system the noisy algorithm model. Our results are confirmed through numerical analysis.

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