The electron density: a fidelity witness for quantum computation

Skogh, Mårten; Dobrautz, Werner; Lolur, Phalgun; Warren, Christopher; Biznárová, Janka; Osman, Amr; Tancredi, Giovanna; Bylander, Jonas; Rahm, Martin

doi:10.1039/d3sc05269a

Cited by 3 publications

(3 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…That being said, the Hohenberg–Kohn theorem states that there is a one-to-one mapping between the external potential and the density. Therefore, in principle, all properties of a system can be determined from the density alone . Here, we showed how energy differences could be obtained from the density, but it is certainly possible that other properties could be obtained using the density information gathered.…”

Section: Discussionmentioning

confidence: 90%

“…Comparison with QPE. If one is already interested in the density at a variety of geometries to calculate properties such as forces acting within molecules 54 or utilize as a fidelity witness 55 by comparing with experiments, the extra evolution time required for QPE is unnecessary as all information to calculate PESs is already present.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, in principle, all properties of a system can be determined from the density alone. 55 Here, we showed how energy differences could be obtained from the density, but it is certainly possible that other properties could be obtained using the density information gathered. One possible route to this is discussed in Section 4.1.2 and ref 51.…”

Section: Regime Of Algorithm Advantagementioning

confidence: 95%

See 2 more Smart Citations

Calculating Potential Energy Surfaces with Quantum Computers by Measuring Only the Density Along Adiabatic Transitions

Brown

2024

J. Chem. Theory Comput.

View full text Add to dashboard Cite

We show that chemically accurate potential energy surfaces (PESs) can be generated from quantum computers by measuring only the density along an adiabatic transition between different molecular geometries. In lieu of using phase estimation, the energy is evaluated by performing line-integration using the inverted real-space time-dependent density functional theory Kohn− Sham (KS) potential obtained from the geometry-varying densities of the full wave function. The accuracy of this method depends on the validity of the adiabatic evolution itself and the potential inversion process (which is theoretically exact but can be numerically unstable), whereas the total evolution time is the defining factor for the precision of phase estimation. We examine the method with a one-dimensional system of two electrons for both the ground and first triplet states in first quantization, as well as the ground state of three-and four-electron systems in second quantization. It is shown that few accurate measurements can be utilized to obtain chemical accuracy across the full potential energy curve, with a shorter propagation time than may be required using phase estimation for a similar accuracy. We also show that an accurate potential energy curve can be calculated by making many imprecise density measurements (using a few shots) along the time evolution and smoothing the resulting density evolution. Finally, it is important to note that the method is able to classically provide a check of its own accuracy by comparing the density resulting from a time-independent KS calculation using the inverted potential with the measured density. This can be used to determine whether longer adiabatic evolution times are required to satisfy the adiabatic theorem.

show abstract

Section: Discussionmentioning

confidence: 90%

Section: Discussionmentioning

confidence: 99%

Section: Regime Of Algorithm Advantagementioning

confidence: 95%

See 1 more Smart Citation

Calculating Potential Energy Surfaces with Quantum Computers by Measuring Only the Density Along Adiabatic Transitions

Brown

2024

J. Chem. Theory Comput.

View full text Add to dashboard Cite

show abstract

ECloudGen: Access to Broader Chemical Space for Structure-based Molecule Generation

Zhang,

Jin,

Lin

et al. 2024

Preprint

View full text Add to dashboard Cite

AI-aided drug design has facilitated structure-based molecule generation strategies. However, despite significant success, the restriction of the scarcity of protein-ligand data prevents the models from fully exploiting the learning chemical space and discovering unexplored potential drugs. The limited chemical space sampling contrasts with the original intention of generation models to explore a broader chemical space, leading to what we term the Chemical Space Generation Paradox. To address the proposed paradox, we developed ECloudGen with the following attributes: (1) Fundamental Physical Representation: We introduce the electron cloud representation, unifying all biological forces under one representation, offering a compact and continuous learning space. (2) Broad and Structurally Ordered Chemical Space: Utilizing electron clouds as generative agents, ECloudGen leverages data without binding structure to access a broader chemical space. In implementation, ECloudDiff as a latent ECloud-based diffusion model is established to sample high-fidelity electron clouds conditioned on pockets’s structure; and CEMP as a novel contrastive learning strategy is proposed to structurally organize the chemical space, thus enabling controllable generation. Subsequent experiments confirm ECloud-Gen’s state-of-the-art performance, in generating chemically feasible molecules with high binding efficacy, drug-likeness, and other chemical properties. Besides, ECloudGen proves to encompass a broader chemical space and also demonstrates superiority in controllable generation in extensive experiments.

show abstract

Current developments and trends in quantum crystallography

Krawczuk,

Genoni

2024

Acta Crystallogr B Struct Sci Cryst Eng Mater

View full text Add to dashboard Cite

Quantum crystallography is an emerging research field of science that has its origin in the early days of quantum physics and modern crystallography when it was almost immediately envisaged that X-ray radiation could be somehow exploited to determine the electron distribution of atoms and molecules. Today it can be seen as a composite research area at the intersection of crystallography, quantum chemistry, solid-state physics, applied mathematics and computer science, with the goal of investigating quantum problems, phenomena and features of the crystalline state. In this article, the state-of-the-art of quantum crystallography will be described by presenting developments and applications of novel techniques that have been introduced in the last 15 years. The focus will be on advances in the framework of multipole model strategies, wavefunction-/density matrix-based approaches and quantum chemical topological techniques. Finally, possible future improvements and expansions in the field will be discussed, also considering new emerging experimental and computational technologies.

show abstract

The electron density: a fidelity witness for quantum computation

Abstract: There is currently no combination of quantum hardware and algorithms that can provide an advantage over conventional calculations of molecules or materials. However, if or when such a point is...

Cited by 3 publications

References 59 publications

Calculating Potential Energy Surfaces with Quantum Computers by Measuring Only the Density Along Adiabatic Transitions

Calculating Potential Energy Surfaces with Quantum Computers by Measuring Only the Density Along Adiabatic Transitions

ECloudGen: Access to Broader Chemical Space for Structure-based Molecule Generation

Current developments and trends in quantum crystallography

Contact Info

Product

Resources

About