- Supersolids combine crystalline order with frictionless superfluid flow.
- Three independent groups confirmed supersolids in 2019 using dipolar BECs.
- Quantized vortices observed in 2024 provided definitive proof of superfluidity.
A supersolid is a quantum state of matter that combines the rigid atomic structure of a crystal with the frictionless flow of a superfluid. Atoms in a supersolid maintain their fixed lattice positions yet move collectively without viscosity, a paradox that physicists debated for decades before confirming it experimentally in 2019.
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1957
Year supersolids were first theorized
Why It Matters
The supersolid occupies a striking position among quantum states. Ordinary solids resist flow. Superfluids flow without friction but lack crystalline order. A supersolid does both simultaneously, and that combination challenges basic assumptions about how matter organizes itself at the quantum scale.
Three independent research groups confirmed supersolid behavior in 2019, working with ultracold clouds of lanthanide atoms (dysprosium and erbium). The teams, based in Innsbruck, Stuttgart, and Florence, each created dipolar Bose-Einstein condensates that spontaneously developed density modulations, the hallmark of crystalline order, while retaining global phase coherence, the signature of superfluidity.
That triple confirmation transformed supersolids from a theoretical curiosity into an active experimental field. Since 2019, research has accelerated. In 2021, Francesca Ferlaino's group at the University of Innsbruck extended supersolids into two dimensions. In November 2024, the same group observed quantized vortices in a rotating supersolid, publishing the results in Nature. Quantized vortices are considered the definitive proof of superfluidity; finding them in a material with crystalline order settled lingering doubts.
How It Works
Creating a supersolid begins with cooling atoms to temperatures near absolute zero, typically around 100 nanokelvin. At these temperatures, bosonic atoms lose their individual identities and merge into a Bose-Einstein condensate, a single quantum state shared by thousands or millions of particles.
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3
Independent groups confirmed supersolids in 2019
The key ingredient is dipolar interaction. Atoms like dysprosium and erbium carry unusually strong magnetic dipole moments. When a BEC of these atoms is tuned using magnetic fields and optical traps, the interplay between short-range contact interactions (which favor uniform density) and long-range dipolar interactions (which favor density modulations) produces a state that is simultaneously ordered and superfluid.
The resulting structure looks like a row of droplets, each containing a few thousand atoms, arranged in a regular pattern. Individually, each droplet behaves as a small BEC. Collectively, the droplets maintain phase coherence across the entire array. Atoms can tunnel between droplets without dissipation. This global coherence is what makes the state supersolid rather than merely a collection of separate condensates.
Key Context
Eugene Gross first proposed the possibility of a supersolid in 1957. Alexander Andreev and Ilya Lifshitz developed the idea further in 1969, suggesting that quantum vacancies in solid helium-4 could create superfluid channels within the crystal lattice.
For decades, helium was the primary candidate. In 2004, Eun-Seong Kim and Moses Chan at Penn State reported anomalous rotational inertia in solid helium that appeared to signal supersolidity. Later experiments showed the effect likely arose from changes in the elastic properties of the helium, not from true superfluid behavior. The helium chapter closed without confirmation.
The breakthrough came from a different direction entirely. Rather than coaxing supersolidity out of a dense solid, physicists built it from scratch using ultracold atomic gases. In January 2026, Leticia Tarruell's team at ICFO in Barcelona captured the first direct images of a supersolid's crystalline vibrations, using spin-orbit-coupled potassium atoms. Their results, published in Science, showed atoms spontaneously forming oscillating stripe patterns that confirmed both crystalline order and superfluid flow.
FAQ
What is the difference between a supersolid and a superfluid?
A superfluid flows without friction but has no internal structure. It behaves like a liquid with zero viscosity. A supersolid also flows without friction, but its atoms are arranged in a repeating crystalline pattern. The supersolid combines both properties in a single quantum state.
Have supersolids been confirmed to exist?
Yes. In 2019, three independent research groups in Innsbruck, Stuttgart, and Florence created supersolids from dipolar Bose-Einstein condensates. In 2024, the observation of quantized vortices in a rotating supersolid, published in Nature, provided definitive proof of superfluidity within a crystalline structure.
Can supersolids exist at room temperature?
Current atomic supersolids require temperatures near absolute zero, around 100 nanokelvin. In 2025, researchers created a polariton-based supersolid using laser light and a gallium oxide semiconductor at higher temperatures. Room-temperature supersolids in bulk matter remain beyond current experimental reach.
How do scientists create supersolids?
Researchers cool atoms with strong magnetic dipole moments (typically dysprosium or erbium) to near absolute zero, forming a Bose-Einstein condensate. They then tune the balance between short-range and long-range atomic interactions using magnetic fields and optical traps until the condensate spontaneously develops both crystalline order and superfluid coherence.
Sources
- Primary Research:
- Two-dimensional supersolidity in a dipolar quantum gas (Norcia et al., Nature, 2021)
- Observation of vortices in a dipolar supersolid (Casotti et al., Nature, 2024)
- Direct imaging of crystalline vibrations in a supersolid (Chisholm et al., Science, 2026)
- Additional Context:
- Physicists prove the existence of a supersolid state of matter (University of Stuttgart, 2019)
Fact Check: Claim-by-Claim Verification Verified
All core claims verified against primary sources. Historical dates, experimental confirmations, and researcher attributions are accurate.
Sources used for verification
- Two-dimensional supersolidity in a dipolar quantum gas - nature.com
- Observation of vortices in a dipolar supersolid - nature.com
- Direct imaging of crystalline vibrations in a supersolid - science.org
- Quantum vortices confirm superfluidity in supersolid - sciencedaily.com
- Direct imaging captures crystalline vibrations of a supersolid - phys.org
