ML4Q Projects
Core Projects
The three Research Areas Processing, Connecting, and Enabling define the scientific orientation and internal structure of ML4Q.
Research Area coordinators and deputies:
Processing: Sebastian Diehl, David Luitz
Connecting: Sebastian Hofferberth, Markus Müller
Enabling: Markus Morgenstern, Thomas Schäpers
P1:
Algorithms and simulations for emergent quantum hardware
Quantum information theorists and computational physicists will team up to develop resource-efficient algorithms and digital quantum simulations, focusing on the ML4Q qubit-boson transmon architecture. One application, based on integrated development between theory and experiment, envisions digital quantum simulations of ‘hard’ condensed matter and high-energy models.
Participants
Bagrets (J)
Barends (J)
Berta (A)
Bluhm (A/J)
Bruß (Dus)
Calarco (J/C)
Funcke (B)
Gross (C)
Kennes (A)
Luitz (B)
Michielsen (J/A)
Motzoi (J/C)
Rizzi (C/J)
Schreiber (A)
Wilhelm-Mauch (J)
Wunderlich (Si)
P2:
Code designs and quantum-error correction protocols
We will investigate topological and non-topological mixed quantum states’ potential to enable long-term scalable fault-tolerant quantum computing. We will develop a new generation of quantum error-correction codes, including LDPC and Floquet codes, and establish paradigms for autonomous, measurement-free fault-tolerant error correction and quantum computing. The project includes proof-of-concept demonstrations for semiconductor-qubit and Rydberg-atom architectures.
Participants
Bergschneider (B)
Bluhm (A)
Diehl (C)
Eisert (BER)
Hofferberth (B)
Kennes (A)
Luitz (B)
Müller (A)
Schreiber (A)
Trebst (C)
Wilhelm-Mauch (J)
P3:
Quantum processors as many-body systems
This project examines the quantum processor from a many-body perspective. It will design hybrid non-unitary protocols including quantum measurement for state preparation and robust information manipulation to achieve a quantum advantage. Applying concepts originating in many-body theory, the project also aims to predict harmful instabilities and propose design principles for maximum resilience. Theoretical ideas will be tested experimentally using the transmon architecture.
Participants
Altland (C)
Barends (J/A)
Buchhold (C)
Diehl (C)
Eisert (BER)
Luitz (B)
Pappalardi (C)
Trebst (C)
Turkeshi (C)
C1:
Processor architectures with long-range links
We build upon pioneering work of ML4Q for Si-semiconductor qubits as well as on neutral atom and molecule arrays. We will advance spin-qubit shuttling in medium dense semiconductor processors to enable quantum gate operations between distant chip areas. For the neutral-atom qubit platform, we aim to establish (1) cavity-mediated all-to-all connectivity and (2) single trapped polar molecules for error-protected qubit encoding. These tasks draw upon the unique expertise available in our consortium – from matter-light interfaces in resonators and free-space, over manipulation of single atoms and molecules in optical tweezers, to precision spectroscopy and quantum metrology with molecules and atoms.
Participants
Bluhm (A/J)
Calarco (J/C)
Hofferberth (B)
Keßler (B)
Kollath (B)
Köhl (B)
Motzoi (J/C)
Mourik (J)
Rizzi (C/J)
Schreiber (A)
Stampfer (A)
Stellmer (B)
Wang (B)
C2:
Interconnecting via optical waveguides
Interconnecting solid-state qubit devices operating in the microwave domain requires optical interfaces, which we will realize via optical waveguides. Combined with quantum frequency conversion for cross-platform connections and fiber-based long-distance quantum information exchange, this lays the groundwork for distributed and cross-platform quantum networks. We will explore two complementary approaches building on the two established qubit platforms in ML4Q, using either spin qubits or Rydberg ensembles as the frequency-transducing element.
Participants
Bluhm (A/J)
Dickel (C)
Hofferberth (B)
Kardynal (J)
Ludwig (Bo)
Pawlis (J)
Witzens (A)
Schüffelgen (J)
Silberhorn (PB)
Stellmer (B)
E1:
2D van-der-Waals materials for quantum information
2D materials open a compelling route toward quantum information hardware. We will establish bilayer graphene qubits as a prospective alternative to existing spin qubit platforms and combine them with molecular single photon emitters for efficient long-distance interconnecting.
Participants
Bergschneider (B)
Hassler (A)
Kennes (A)
Kroha (B)
Kurzmann (C)
Linden (B)
Morgenstern (A)
Stampfer (A)
Viola Kusminskiy (A)
Wang (B)
E2:
Majorana qubits
We believe that Majorana topological qubits based on topological-insulator/superconductor hybrids offer a promising route to protected quantum computing. A key intermediate goal is to demonstrate Majorana braiding, paving the way for fault-tolerant operations in the Majorana subspace. In parallel, we will develop a scalable platform to host this prototype technology and pursue device concepts for mobile Majorana qubits defined via topological-insulator vortex states.
Participants
Ando (C)
Bocquillon (C)
Blügel (J)
Breunig (C)
Dickel (C)
Dunin-Burkowski (J)
Egger (Dus)
Grützmacher (J)
Hassler (A)
Klinovaja (B)
Moors (J)
Morgenstern (A)
Rosch (C)
Schäpers (J)
Schüffelgen (J)
Taskin (C)
Tautz (J)
E3:
Entangling photonic Bose-Einstein condensates
We will investigate how microcavity photons, forming photonic Bose–Einstein condensates, can serve as a resource for multipartite entanglement and potentially for quantum computing.
Participants
Bruß (Dus)
Kroha (B)
Schmitt (B)
Weitz (B)