Gemini Center on Quantum Technology

Welcome to the future!

The Gemini Center on Quantum Technology was established in 2020 with a focus on Quantum Computation. In 2024, its scope expanded to include Quantum Sensors and Materials, as well as Quantum Communication and Security. The Center works to coordinate quantum research across Norway and to strengthen Norway’s position as a leading contributor to future quantum technologies.

We work closely with Norsk Kvanteklynge, which brings together government, industry, and other strategic stakeholders.

Main Partners:

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Associate Partners:

We have the following three scientific tracks.

Communication

Communication Track

Utilize the principles of quantum mechanics to transmit information.

Computing

Compute Track

Utilize the principles of quantum mechanics for computation.

Sensors

Sensors and Materials Track

Utilize the principles of quantum mechanics for sensing.

Join the Google Groups to stay up to date with each of the tracks.

Talks from past events

Speaker:Franz G. Fuchs Title: Encoding Combinatorial Problems with Integer Variables into Qubits: An application to the MAX k-CUT  problem Abstract: The weighted MAX k-CUT problem involves partitioning a weighted undirected graph into k subsets, or colors, to maximize the sum of the weights of edges between vertices in different subsets. This problem has significant applications across multiple domains. This paper explores encoding methods for MAX k-CUT on qubit systems, utilizing quantum approximate optimization algorithms (QAOA) and addressing the challenge of encoding integer values on quantum devices with binary variables. We examine various encoding schemes and evaluate the efficiency of these approaches. The paper presents a systematic and resource efficient method to implement phase separation operator for the cost function of the MAX k-CUT problem. When encoding the problem into the full Hilbert space, we show the importance of encoding the colors in a balanced way. We also explore the option to encode the problem into a suitable subspace, by designing suitable state preparations and constrained mixers (LX-and Grover-mixer). Numerical simulations on weighted and unweighted graph instances demonstrate the effectiveness of these encoding schemes, particularly in optimizing circuit depth, approximation ratios, and computational efficiency.
Encoding Combinatorial Problems with Integer Variables into Qubits: The MAX k-CUT problem
Speaker:Håkon R. Fredheim Title: A Novel Mathematical Formulation of Density Functional Theory Abstract: In this talk, I present my recent work with Simen Kvaal, where we developed a novel mathematical framework for density functional theory (DFT), the “gold standard method” used in large-scale many-particle quantum chemistry calculations. I present some preliminary results, where we address some open mathematical questions in DFT using our framework. Paper: https://arxiv.org/abs/2510.12242
A Novel Mathematical Formulation of Density Functional Theory
Speaker: Franz Luef, NTNU Title: Novel methods for quantum information processing Abstract: In this talk I present a way to transfer methods from signal processing, like the short-time Fourier transform or the wavelet transform and the respective reconstruction formulae, to the quantum setting. This approach works for discrete variables and continuous variables quantum systems. The focus is going to be on the operator short-time Fourier transform and the polarized Cohen’s class of an operator. This is joint work with Monika Doerfler, Henry McNulty and Eirik Skrettingland.
Novel methods for quantum information processing
Monthly track meeting for the Gemini Center on Quantum Technology's Quantum Communication and Security track, November 11 2025. https://quantumnorway.no/communication-track/ Speaker: Hans Heum Title: Cryptographic Group Actions in a Quantum World Abstract: The Group Action formalism generalizes the familiar discrete-logarithm based hardness assumptions in such a way that post-quantum security can be recovered. In particular, post-quantum group actions have been shown to be instantiable from isogeny-based cryptography, such as CSIDH and more recently PEGASIS. Thus, many useful results from the world of Diffie-Hellman assumptions can be ported to a post-quantum setting. Some such results are only known to hold in generic models like the Generic Group Model (GGM) and the Algebraic Group Model (AGM), in which the groups are idealized in one of two ways. Recent works have ported these models to the setting of group actions, giving the Generic Group Action Model (GGAM) and the Algebraic Group Action Model (AGAM). But much like how post-quantum security requires going from the classical to the quantum random oracle model (QROM) when modelling hash functions, we would often need quantum variants of the GGAM and the AGAM to be able to argue post-quantum security for group actions. Coming up with sound definitions of these models, however, has turned out to be more challenging than expected. In this talk I will introduce group actions, then survey the attempts that have been made so far at defining quantum generic models for them, and the challenges that each attempt has faced—together with some ideas for how we might try to resolve them. Based on ongoing work with Doreen Riepel.
Cryptographic Group Actions in a Quantum World
In which Oskar Goldhahn tells us about some of the techniques underlying the automated verification of classical and quantum algorithm implementations. Monthly track meeting for the Gemini Center on Quantum Technology's Quantum Communication and Security track, October 10 2025. https://quantumnorway.no/communication-track/ Speaker: Oskar Goldhahn, NTNU Abstract: We present some of the machinery used to formally verify the correct implementation of classical algorithms, including post-quantum cryptography, and how this can be extended to algorithms that use quantum computers.
Formally Verifying Functional Correctness in a Quantum World
In which Alexander Mueller-Hermes tells us how error-correcting codes work when the communication channels are quantum. Monthly track meeting for the Gemini Center on Quantum Technology's Quantum Communication and Security track, September 12 2025. https://quantumnorway.no/communication-track/ Speaker: Alexander Mueller-Hermes, UiO Abstract: Designing encoding and decoding circuits to reliably send messages over many uses of a noisy channel is a central problem in communication theory. When studying the optimal transmission rates achievable with asymptotically vanishing error it is usually assumed that these circuits can be implemented using noise-free gates. While this assumption is satisfied for classical machines in many scenarios, it is not expected to be satisfied in the near term future for quantum machines where decoherence leads to faults in the quantum gates. As a result, fundamental questions regarding the practical relevance of quantum channel coding remain open. By combining techniques from fault-tolerant quantum computation with techniques from quantum communication, we initiate the study of these questions. We introduce fault-tolerant versions of quantum capacities quantifying the optimal communication rates achievable with asymptotically vanishing total error when the encoding and decoding circuits are affected by gate errors with small probability. Our main results are threshold theorems for the classical and quantum capacity: For every quantum channel T and every ϵ greater than 0 there exists a threshold p(ϵ, T ) for the gate error probability below which rates larger than C − ϵ are fault-tolerantly achievable with vanishing overall communication error, where C denotes the usual capacity. Joint work with Matthias Christandl. For more information see: https://arxiv.org/abs/2009.07161
Fault-tolerant coding for quantum communication
Speaker: Konrad Tywoniuk, University of Bergen Abstract: Community detection, also known as graph partitioning, is a well-known NP-hard combinatorial optimization problem with applications in diverse fields such as complex network theory, transportation, and smart power grids. The problem's solution space grows drastically with the number of vertices and subgroups, making efficient algorithms crucial. In recent years, quantum computing has emerged as a promising approach to tackling NP-hard problems. This study explores the use of a quantum-inspired algorithm, Simulated Bifurcation (SB), for community detection. Experimental results demonstrate that SB effectively identifies community structures in benchmark networks such as Zachary's Karate Club and the IEEE 33-bus system. SB achieved high modularity, matching the performance of Fujitsu's Digital Annealer, and surpassing results obtained from two quantum machines, D-Wave and IBM. These findings highlight the potential of SB as a powerful tool for solving community detection problems.
Community detection by simulated bifurcation
In this talk, I will give an introduction to some methods used for solving many-body problems. I will introduce some relevant concepts and notation that are essential in understanding such systems. In particular, I will focus on Coupled Cluster methods, and their mathematical description. These methods have wide applications ranging from nuclear physics to quantum chemistry. Recently, there have been great advances on the mathematical description of Coupled Cluster methods. I have been working with Nadia Larsen, Simen Kvaal, Sergiy Neshveyev and Snorre Bergan on some new results on Coupled Cluster methods, and I will present these.
A Mathematical Approach to Coupled Cluster Methods
Speaker: Hsuan-Yin Lin, Simula Abstract: Quantum error correction is the foundation for protecting quantum systems and scaling up the number of quantum devices to perform highly complex tasks. In this talk, we will give a gentle introduction to one of the well-known families of quantum error-correcting codes, the quantum stabilizer codes, which have been developed since 1990 by Shor, Laflamme, and Gottesman, among others. Such codes have also recently been discovered to make quantum computers much more efficient than before. We will discuss the main feature for decoding quantum stabilizer codes, degeneracy, which does not occur in the classical world but from a classical-friendly perspective.
Quantum Error Correction from a Classical-Friendly World-View
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