Quantum fluctuations—the ever-present, spontaneous changes in energy that occur even in the void of empty space—have long fascinated physicists. These fluctuations persist even at temperatures approaching absolute zero, a realm where classical physics predicts an utter stillness. Their subtle influence can manifest in surprising ways within materials, especially those structured at the atomic scale. Recent groundbreaking research has now demonstrated a profound consequence of these vacuum fluctuations: they can fundamentally alter the properties of a nearby superconducting crystal without the need for external stimulation. This discovery marks a key milestone in materials science and quantum physics, opening the door to novel methods of manipulating electronic properties by harnessing the untapped power of quantum cavities.
Superconductivity, the phenomenon where materials conduct electricity with zero resistance, has captivated scientists for over a century due to its enormous potential for lossless energy transfer and transformative technological applications. Despite decades of study, controlling and tuning superconductivity remains a formidable challenge. A new study led by Professor Dmitri Basov and an international team of 33 researchers from 17 institutions has experimentally confirmed a novel approach: altering superconductivity using quantum fluctuations in a carefully engineered two-dimensional structure. This approach leverages the unique electromagnetic environment formed between ultra-thin layers of hexagonal boron nitride (hBN) and an adjacent superconducting crystal, κ-(BEDT-TTF)₂Cu[N(CN)₂]Br (κ-ET).
This pioneering experiment positioned a few-nanometer-thick slice of hBN—an ultra-stable, insulating van der Waals material renowned for its hyperbolic electromagnetic properties—directly atop the κ-ET superconductor. Importantly, no external light sources, mechanical stresses, or thermal perturbations were applied. Despite this, the superconducting state within the κ-ET was notably suppressed. The discovery validates a previously theoretical possibility that quantum vacuum fluctuations trapped within a nanoscale cavity can mediate interactions strong enough to modify the electronic phases of nearby materials, marking the first clear experimental evidence of cavity-altered superconductivity.
The core concept underpinning this effect lies in the resonance matching between the intrinsic vibrations, or phonon modes, within the hBN flake and the excitation spectrum of the κ-ET superconductor below. Basov and his postdoctoral fellows Itai Keren, Tatiana Webb, and Shuai Zhang hypothesized that when hBN’s hyperbolic phonons resonate in harmony with the κ-ET’s electronic system, quantum fluctuations will interact with those electrons and disrupt their coherence, which is essential for the superconducting phase to manifest. Through careful measurements, they confirmed that this interaction changes the electromagnetic environment fundamentally, impeding the electron pairs (Cooper pairs) responsible for superconductivity, thereby causing a dramatic suppression of the zero-resistance state.
Prior to these experiments, the idea that vacuum fluctuations alone—fluctuations in an electromagnetic cavity devoid of external excitation—could induce such macroscopic changes in material properties was met with healthy skepticism. The notion originally germinated in scientific discussions between Basov and theoretical collaborator Angel Rubio. Rubio, who brought his expertise from the Max Planck Institute for the Structure and Dynamics of Matter, initially proposed that quantum vacuum fields inside nanocavities could modulate materials’ electronic phases. Basov, despite his doubts, embraced the experimental challenge, recognizing the unique optical signatures of hBN and its potential to serve as an ultra-thin quantum cavity.
hBN has long been a staple in the toolkit of nanotechnology and materials science, primarily valued as an inert encapsulation or insulating layer. However, hBN’s hyperbolic nature—where its dielectric permittivity exhibits opposite signs along perpendicular crystallographic axes—favours enhanced electromagnetic modes deeply confined within the crystal lattice. This hyperbolicity amplifies quantum fluctuations, acting as a nanoscale resonant cavity without traditional mirrors. These confined vacuum fields can generate phonon polaritons, hybrid light-matter excitations, that vibrate at frequencies matched to the vibrational modes in κ-ET, setting the stage for strong coupling between the layers even in the absence of light.
To detect these elusive and delicate effects, the research team combined advanced experimental tools, notably a cryogenic magnetic force microscope (MFM). This cutting-edge technique senses the Meissner effect—the magnetic field expulsion indicative of superconductivity—through the intervening hBN layers at ultra-low temperatures, effectively allowing the scientists to “see” the superconducting state beneath without light-induced artifacts. This direct probing confirmed that the superconductivity in κ-ET was disrupted significantly over lateral distances much larger than the thickness of the hBN layer itself, illuminating a long-range influence of the vacuum fluctuations.
One of the most striking findings was the magnitude of this vacuum-mediated suppression: it extended about half a micrometer from the site of the hBN flake, roughly ten times the hBN thickness. Such a pronounced and spatially extended effect demonstrates that quantum cavity interactions can act as a powerful and noninvasive “knob” to tune superconductivity in layered materials. This is a paradigm shift away from traditional methods that rely on thermal, mechanical, or photonic excitation, which often produce transient and less controllable changes.
The implications are profound not only for superconductors but potentially for a wider class of quantum materials, including magnets and ferroelectrics, each defined by characteristic lattice vibrations. By tailoring cavity materials like hBN to possess resonances that couple to the target material’s excitations, it may become possible to engineer new quantum phases with custom properties, simply by designing the quantum vacuum environment. This quantum cavity approach could usher in a technological revolution in material science, facilitating the on-demand manipulation of quantum states without direct energy inputs.
While the experimental evidence is compelling, theoretical understanding is still catching up. Researchers continue to develop comprehensive models to fully elucidate the mechanisms by which vacuum fluctuations couple to and modify collective electronic states. The complexity of multi-mode coupling, dissipation, and the interplay of quantum coherence challenge existing frameworks. Nonetheless, this breakthrough firmly establishes the experimental reality of vacuum-induced material modification, validating a frontier once thought purely theoretical.
This research also underscores the powerful synergy between fundamental physics and material engineering. The deployment of two-dimensional materials as quantum cavities reallocates what was once considered inert or simple layered spacers into active components in quantum devices. Progressive tuning of hBN’s thickness—a straightforward geometric modification—offers a versatile handle to modulate interaction strength and resonance frequencies, opening pathways to customizable material properties engineered at the atomic scale.
In sum, the discovery that quantum vacuum fluctuations within nanometer-thick hexagonal boron nitride cavities can profoundly alter superconductivity in nearby materials represents a transformative leap forward. It reveals a new paradigm where the vacuum itself—the supposedly empty quantum space—acts as an active participant capable of sculpting the electronic landscape of materials. This feat extends beyond science fiction: it pioneers a new frontier in quantum materials design where quantum noise becomes an instrument rather than an obstacle, lighting a path for future advances in quantum computing, sensing, and beyond.
The full details of this research were published recently in the highly prestigious journal Nature, signifying the importance and broad interest of these findings within the physics and materials science communities. The collaboration between theorists and experimentalists, coupled with state-of-the-art measurement techniques, stands as a testament to the power of interdisciplinary approaches in pushing the boundaries of what we can observe and manipulate in the quantum world. As these insights deepen, the prospect of engineering quantum materials by the artful control of vacuum fluctuations hints at revolutionary applications right on the horizon.
Subject of Research: Quantum fluctuations, 2D materials, superconductivity, cavity quantum electrodynamics
Article Title: Cavity-altered superconductivity
News Publication Date: 25-Feb-2026
Web References:
DOI: 10.1038/s41586-025-10062-6
Image Credits: Ella Maru Studio
Keywords
Superconductivity, Two dimensional materials, Quantum fluctuations, Light matter interactions, Cavity quantum electrodynamics, Quantum optics
Tags: atomic scale material engineeringDmitri Basov superconductivity researchelectromagnetic environment effects on superconductivitymanipulating electronic properties quantumlynovel methods for superconductivity controlquantum cavity-induced material transformationquantum fluctuations in materialsquantum physics in material sciencetuning superconductivity with quantum cavitiestwo-dimensional superconducting materialsvacuum fluctuations affecting superconductorszero resistance energy transfer materials
