New method reveals hidden energy-loss pathway in silicon carbide quantum defects

Overview

Updated 2 hours ago

For years, predictions about how silicon carbide defects shed energy didn't match experiments. University of Chicago researchers now know why. A process called internal conversion, where energy dissipates as atomic vibrations rather than light, plays a far bigger role than earlier models accounted for.

The finding, published in Physical Review Letters, resolves a discrepancy that has puzzled researchers. It could improve the design of qubits for quantum computers and sensors. The same computational framework may also apply to materials used in renewable energy conversion and storage.

Why it matters

Accurate predictions of how quantum defects lose energy could speed the design of qubits for quantum computers and sensors.

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Key Indicators

Materials validated

Method matched spectroscopy for diamond and revealed new behavior in silicon carbide

Hundreds

Atoms coupled in calculations

The method computes how each excited state couples to vibrations of hundreds of nearby atoms

Voices

Curated perspectives — historical figures and your fellow readers.

Ever wondered what historical figures would say about today's headlines?

People Involved

Giulia Galli

Liew Family Professor of Molecular Engineering, University of Chicago Pritzker School of Molecular Engineering

Led the research team

Yu Jin

Postdoctoral scholar, Flatiron Institute (former graduate student in Galli's group)

Co-developed the new formulation

Villani

Researcher, University of Chicago Pritzker School of Molecular Engineering

Co-developed the new formulation

Organizations Involved

University of Chicago Pritzker School of Molecular Engineering

Academic research institution

Host institution for the research

The Pritzker School of Molecular Engineering at the University of Chicago conducts research at the intersection of molecular science and engineering.

WEST code

Computational framework

Now includes the internal conversion framework

A computational code for simulating materials at the quantum level, now including the new internal conversion framework.

Timeline

1 event Latest: Today

October 2026
Internal conversion framework published
Today Research

University of Chicago team publishes method revealing internal conversion's outsized role in silicon carbide defects.
Today

Scenarios

Silicon carbide qubit designs shift to account for internal conversion

Likely Resolves by Oct 23, 2027

Discussed by: The researchers suggest the findings could inform qubit development

Research groups use the WEST framework to model silicon carbide divacancy defects, leading to revised predictions of qubit lifetimes and new design strategies. The corrected understanding of internal conversion could change which defects are considered viable qubits.

Method extends to renewable energy materials

Possible Resolves by Oct 23, 2028

Discussed by: The researchers note the method could apply to renewable energy conversion and storage

The framework is applied to materials used in solar energy conversion or battery storage, revealing similar internal conversion effects that affect efficiency. This would broaden the method's impact beyond quantum technologies.

WEST framework becomes standard tool for defect modeling

Possible Resolves by Oct 23, 2028

Discussed by: The framework is already built into WEST, available to other labs

Multiple research groups adopt the framework, leading to a broader understanding of internal conversion across defect types and materials. This would establish the method as a standard tool in the field.

Historical Context

3 moments from history that rhyme with this story — and how they unfolded.

1965

Density functional theory (1965)

Walter Kohn and Lu Jeu Sham published equations that let scientists calculate the electronic structure of materials from first principles. The method became the standard tool of computational materials science.

Then

Researchers could model real materials on computers for the first time.

Now

DFT became the foundation of modern computational materials science, used in thousands of studies each year.

Why this matters now

The WEST code builds on DFT, extending it to describe excited states and defects. This new work continues that tradition.

1997

Nitrogen-vacancy center in diamond (1997)

Researchers demonstrated that a single nitrogen-vacancy defect in diamond emits single photons at room temperature. The defect later became a leading platform for quantum sensing.

Then

Scientists gained a stable, readable quantum system at room temperature.

Now

NV centers became a workhorse for quantum sensing, with applications in magnetic field detection and imaging.

Why this matters now

The researchers validated their new method against NV center measurements, confirming it matched known behavior before applying it to silicon carbide.

1965

GW approximation (1965)

Lars Hedin introduced the GW approximation, a method for describing how electrons interact in materials. It became a key tool for calculating excited-state properties.

Then

Scientists could calculate band gaps and excited states more accurately than with DFT alone.

Now

GW methods became standard for predicting the electronic properties of materials, including defects.

Why this matters now

The WEST code uses many-body perturbation theory, which includes GW methods, to describe how defects interact with light and atomic motion.