Draft:Roman Orus

Román Orús Lacort (Barcelona, 1979) is a Spanish theoretical physicist and entrepreneur. He is Ikerbasque Research Professor at the Donostia International Physics Center (DIPC), as well as co-founder and Chief Scientific Officer of Multiverse Computing.

Academic Career
Román Orús studied physics at the University of Barcelona where he obtained his Ph.D. supervised by José Ignacio Latorre in 2006. Afterwards he worked as a research fellow at the University of Queensland (Brisbane, Australia) with Guifré Vidal, and at the Max Planck Institute of Quantum Optics (Garching, Germany) with Ignacio Cirac. He became Junior Professor of Condensed Matter Physics at the Johannes Gutenberg-Universität (Mainz, Germany) in 2013, and Ikerbasque Research Professor at DIPC (San Sebastián, Spain) in 2018, at the age of 38. He also held visiting professorships at CNRS (Toulouse, France) and DIPC.

Scientific Work
Orús' doctoral thesis was the first in Spain on quantum algorithms, connecting them with quantum phase transitions. To date, he has published more than 100 scientific papers in Nature, Physical Review Letters and other journals, receiving thousands of citations. During his time in Australia, he pioneered the use of infinite Projected Entangled Pair States to study two-dimensional quantum lattice systems in the thermodynamic limit with G. Vidal, I. Cirac, F. Verstraete and J. Jordan, including the proposal with G. Vidal of a directional corner transfer matrix approach. In 2013 he wrote a review on tensor networks states which has since received over 2,000 citations, as well as follow-up papers on the topic. Orús also obtained results on quantum many-body entanglement, including the discovery with T.-Chieh Wei, O. Buerschaper and M. van den Nest of a topological correction in the geometric entanglement of topologically-ordered systems. In 2018, he wrote an article with S. Mugel and E. Lizaso on the practical applications of quantum computing in finance that demonstrates the potential impact of quantum computing in the financial industry which eventually led to the creation of Multiverse Computing.

Orús has also made contributions at the crossover between physics and linguistics. For instance, he proposed the connection between language and renormalization, and introduced matrix models and vector spaces to describe syntax. In cybersecurity,  Orús also developed examples of possible quantum cyberattacks for symmetric-key cryptographic protocols such as AES and Blowfish that could make those ciphers vulnerable using few-qubit quantum processors.

Orús also was one of the first researchers to develop tensor networks to study high-dimensional quantum complex systems at the University of Queensland in 2006. Later, he pioneered its application to industrial problems, for instance by using tensor networks for portfolio optimization using real-life data with a multinational bank. With Multiverse, he also developed industrial applications of tensor networks for machine learning, and more recently, he used tensor networks to classically simulate kicked Ising experiments on quantum processors with more than 1,000 qubits , disproving claims on the hardness to simulate such experiments classically [19]. He has also recently used tensor networks to compress Large Language Models such as ChatGPT and LLaMA, reducing size while retaining most of the original accuracy to improve energy costs and efficiency.

Awards
Orús has received several awards for his scientific work, including an Honorable Mention in the Václav Votruba Prize (2008), a Marie Curie Incoming International Fellowship (2009) and the Early Career Prize of the European Physical Society (2014), which he won alongside Ian Chapman. With Multiverse Computing, Orús work was recognized by winning DIGITALEUROPE's Future Unicorn Award (2024) and CB Insights' Top 100 Most Promising AI Startup Recognition (2023).

Business Career
In 2019, together with E. Lizaso, S. Mugel and A. Rubio, Orús co-founded Multiverse Computing focused on quantum and quantum-inspired software solutions. Multiverse incorporated as a company in 2019 in San Sebastián (Spain) with the support of DIPC, BIC-Gipuzkoa and local authorities.

With applications in finance, energy, healthcare, cybersecurity, logistics, and smart manufacturing, the company has been recognized for its intellectual property as a top 3 patent contributor in Spain.

Orus’ work and commentary on AI and quantum computing have been broadly featured in the media.

Other Activities
Orús is steering board member of the journal Quantum, editor of the journal Symmetry, a member of the Quantum for Quants commission of the Quantum World Association, partner at Entanglement Partners, member of the Scientific Committee of the Pedro Pasqual Benasque Center for Science (CCBPP), and former president of the Specialized Group on Quantum Information at the Spanish Royal Physics Society. Since 2012, he has also co-organized one of the leading conferences worldwide on strongly correlated systems at the CCBPP. He serves regularly as reviewer and advisor of several journals and institutions and is often involved in outreach activities.

Selected Academic Works
P Bermejo, R Orús, (August 2023). “Variational quantum and quantum-inspired clustering,” Scientific Reports 13 (1), 13284

S Mugel, C Kuchkovsky, E Sanchez, S Fernandez-Lorenzo, J Luis-Hita, E Lizaso, R Orús, (January 2022). “Dynamic portfolio optimization with real datasets using quantum processors and quantum-inspired tensor networks,” Physical Review Research 4, 013006

H Weimer, A Kshetrimayum, R Orús, (March 2021). “Simulation methods for open quantum many-body systems,” Reviews of Modern Physics 93, 015008

R Orús, (August 2019). “Tensor networks for complex quantum systems,” Nature Reviews Physics 1, 538-550

R Orús, S Mugel, E Lizaso, (November 2019). “Quantum computing for finance: Overview and prospects,” Reviews in Physics 4, 100028

A Kshetrimayum, H Weimer, R Orús, (November 2017). “A simple tensor network algorithm for two-dimensional steady states,” Nature communications 8 (1), 1-7

R Orús, (October 2014). “A practical introduction to tensor networks: Matrix product states and projected entangled pair states,” Annals of physics 349, 117-158, 2014

P Corboz, R Orús, B Bauer, G Vidal, (April 2010) “Simulation of strongly correlated fermions in two dimensions with fermionic projected entangled-pair states,” Physical Review B 81 (16), 165104

J Jordan, R Orús, G Vidal, F Verstraete, I Cirac, (December 2008). “Classical simulation of infinite-size quantum lattice systems in two spatial dimensions,”, Physical Review Letters 101 (25), 250602

JI Latorre, R Orús, (June 2004). “Adiabatic quantum computation and quantum phase transitions,” Physical Review A 69 (6), 062302, 72