Christian F. Roos

Also known as Christian Roos, Christian Felix Roos

Christian F. Roos is an experimental physicist whose trapped-ion experiments in Innsbruck build hardware for quantum computing and quantum simulation. He studied physics at Göttingen, earned his PhD with Rainer Blatt at the University of Innsbruck in 2000, and worked as a postdoctoral fellow at the Laboratoire Kastler Brossel in Paris before returning to Innsbruck. In 2008 his team built a two-ion quantum gate with 99.3 percent fidelity, and in 2011 he co-authored a digital quantum simulator made from calcium ions; an ERC Advanced Grant in 2017 funded a simulator for two-dimensional ion crystals, and a 2023 research prize honored his 50-ion quantum simulator. He leads trapped-ion experiments as a group leader at the University of Innsbruck's Institute of Experimental Physics and as a senior scientist at the Institute for Quantum Optics and Quantum Information.

Now at: Universität Innsbruck and Austrian Academy of Sciences
Badges: Loyal

Timeline

1989–2000

Göttingen physics, Innsbruck PhD

He studies physics at Georg August Universität Göttingen from 1989 and begins graduate work with Rainer Blatt at the Universität Innsbruck in 1995. He earns his PhD in 2000 with a thesis titled "Controlling the quantum state of trapped ions".
2000–2005

Paris postdoc, then IQOQI

From 2000 to 2002 he is a postdoctoral fellow, with a Marie Curie fellowship, at the Laboratoire Kastler Brossel of the École normale supérieure, working with Jean Dalibard and David Guéry-Odelin. After three years as a university assistant at Innsbruck, he moves to the new Institute for Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences, where he works as a senior scientist in Rainer Blatt's research group.
2008

A 99.3 percent two-ion gate

In 2008, Roos, Rainer Blatt and the doctoral students Jan Benhelm and Gerhard Kirchmair build a Mølmer–Sørensen gate from two calcium ions that reaches a fidelity of 99.3 percent. They publish it as "Towards fault-tolerant quantum computing with trapped ions" in Nature Physics.
2011

A digital quantum simulator

In 2011, Roos and colleagues, including Ben Lanyon and Rainer Blatt, publish "Universal digital quantum simulation with trapped ions" in Science. Calcium ions serve as quantum bits, and the team runs simulations on up to six quantum bits with up to 100 gate operations.
2017

An ERC Advanced Grant

In March 2017, he receives an ERC Advanced Grant of up to 2.5 million euros over five years to build a new type of quantum simulator. The plan is a cryogenic trap for two-dimensional ion crystals, with the goal of controlling up to 100 ions at the same time.
2023

Research prize for a 50-ion simulator

In 2023, the University of Innsbruck gives him a research prize in the name of the Stiftung Südtiroler Sparkasse for the publication "Realization of a 50-qubit trapped ion quantum simulator". The work extends the Innsbruck quantum simulator from 20 to more than 50 ions and uses it to study how magnetic excitations spread in a quantum many-body system.
January 2025

An ERC Proof-of-Concept grant

In January 2025, the University of Innsbruck announces that he has secured an ERC Proof-of-Concept Grant to implement quantum gate operations in two-dimensional ion crystals. The project builds on his Advanced Grant work, aims at a new geometry for ion-based quantum computers, and involves the spin-off company Alpine Quantum Technologies.
As of October 2026

Group leader in Innsbruck

As of October 2026, he leads the Quantum Optics and Spectroscopy group at the University of Innsbruck's Institute of Experimental Physics and is a senior scientist in the Blatt workgroup at IQOQI. His group turns a few tens of trapped ions into a many-body system for simulating quantum magnetism and develops entanglement-based measurement methods.