Scientists at CERN’s BASE collaboration achieved the first-ever coherent spectroscopy of a single antiproton spin, keeping an antiproton oscillating between quantum spin states for 50 seconds[^1]. This breakthrough, published in Nature on July 23, 2025, marks the first demonstration of an antimatter quantum bit (qubit)[^2].

The team used electromagnetic Penning traps to isolate and manipulate individual antiprotons, achieving spin inversion probabilities above 80% during the coherent oscillations[^3]. By suppressing decoherence mechanisms that previously limited precision, they performed quantum measurements with transition linewidths 16 times narrower than previous experiments[^4].

“This represents the first antimatter qubit and opens up the prospect of applying the entire set of coherent spectroscopy methods to single matter and antimatter systems in precision experiments,” said BASE spokesperson Stefan Ulmer[^5]. While the antimatter qubit won’t be used for quantum computing, it enables ultra-precise tests of matter-antimatter symmetry[^6].

The next phase involves BASE-STEP, which will transport antiprotons to calmer magnetic environments. “Once it is fully operational, our new offline precision Penning trap system could allow us to achieve spin coherence times maybe even ten times longer than in current experiments,” said lead author Barbara Latacz[^7].

[^1]: Nature (@nature.com) - Nature research paper: Coherent spectroscopy with a single antiproton spin

[^2]: CERN - Breakthrough: First Coherent Spectroscopy with a Single Antiproton Spin

[^3]: Heinrich Heine University - News

[^4]: Nature - Coherent spectroscopy with a single antiproton spin

[^5]: CERN - A quantum leap for antimatter measurements

[^6]: Interesting Engineering - Scientists trap antiproton for 50 seconds in first antimatter qubit

[^7]: Space.com - Scientists just made the 1st antimatter ‘qubit.’