Quantum Computing Achieves Spectral Gap Estimation Using 20 Qubits and Adiabatic Preparation

Determining the energy differences between quantum states, known as spectral gaps, presents a fundamental challenge in understanding the behaviour of quantum systems. Davide Cugini, Francesco Ghisoni, Angela Rosy Morgillo, and Francesco Scala, all from the Dipartimento di Fisica at the Università degli Studi di Pavia, introduce a novel method for estimating these crucial gaps using digital quantum devices. Their approach employs the Adiabatic Preparation technique to create a unique superposition state, and then analyses the resulting time-dependent fluctuations in observable measurements to accurately determine the energy gap. This technique successfully estimates spectral gaps in systems ranging from simple models like the 1D and 2D Ising models to complex molecules such as hydrogen and helium, and importantly, demonstrates robustness on both simulated and real quantum hardware, including a 20-qubit device, opening new avenues for energy gap calculations with increasingly complex quantum systems.

Quantum Spectral Gap Estimation with Computers

Scientists developed a novel method for estimating spectral gaps in quantum systems, circumventing traditional approaches that require independent calculation of ground and excited state energies. The study pioneered the use of Adiabatic Preparation, a technique used to create a specific superposition state, from two eigenstates of the system’s Hamiltonian. This superposition is initialized using an auxiliary Hamiltonian and then evolved to represent the target system, allowing researchers to bypass the need to know the eigenstates analytically. The core of the method involves measuring time-dependent fluctuations in the expectation values of observables, which are then used in a fitting process to directly estimate the energy gap.,.

Adiabatic Preparation Estimates Quantum Energy Gaps

Scientists have developed a new method for estimating energy gaps in quantum systems, a crucial step in understanding their properties, using a technique called Adiabatic Preparation. This work bypasses the traditional approach of individually calculating ground and excited state energies, instead leveraging time-dependent fluctuations of observable measurements on a specifically prepared superposition state. The team successfully implemented this method on both simulated quantum systems and real quantum hardware, demonstrating its potential for currently available digital quantum devices.,.

Adiabatic Preparation Estimates Quantum Energy Gaps

This work introduces a novel method for estimating energy gaps in quantum systems, a crucial parameter for understanding material properties and molecular behaviour. Rather than directly calculating the ground and excited states, the team employed the Adiabatic Preparation technique to create a specific superposition state, then analysed time-dependent fluctuations in observable expectation values. The researchers demonstrated the robustness of their approach on the IonQ Aria device for the 1D Ising model, extending to systems of up to 20 qubits. This achievement indicates the method’s applicability to currently available digital quantum devices, and lays the groundwork for tackling more complex energy gap calculations as quantum hardware improves.,.

Adiabatic Preparation Estimates Quantum Energy Gaps

Scientists have demonstrated a new pathway to estimate energy gaps in quantum systems, a crucial parameter for understanding material properties and molecular behaviour. The team employed the Adiabatic Preparation technique to create a specific superposition state and then analysed time-dependent fluctuations in observable expectation values. This approach eliminates the need for individual energy eigenvalue calculations, paving the way for tackling complex quantum systems that are currently intractable for classical computers. Measurements confirm the method’s robustness and applicability to currently available digital quantum devices, opening new avenues for exploring quantum phenomena and developing future quantum technologies.