“Who knows if we could be celebrating 2025 as the @QuantumYear2025 if Max Born, Wolfgang Pauli, and Pascual Jordan hadn’t happened to meet by chance on a train in July 1925. Two months later, the mathematical elaboration of Werner Heisenberg’s idea of quantum mechanics was on the table.” An article in the leading daily newspaper @Tagesspiegel on #Berlin as a place for doing good research on quantum science and technology. And what @Berlin_Quantum and several other initiatives have to do with it. tagesspiegel.de/themenspezia…

Universal fault-tolerant logic with heterogeneous holographic codes scirate.com/arxiv/2504.10386 This is an attempt of bringing #holographic codes for #quantumerrorcorrection closer to practicalities of #quantumcomputing. In detail, the study of holographic bulk-boundary dualities has led to the construction of novel quantum error correcting codes. Although these codes have shed new light on conceptual aspects of these dualities, they have widely been believed to lack a crucial feature of practical quantum error correction: The ability to support universal #faulttolerant quantum logic. In this work, we introduce a new class of holographic codes that realize this feature. These heterogeneous holographic codes are constructed by combining two seed codes in a tensor network on an alternating hyperbolic tiling. We show how this construction generalizes previous strategies for fault tolerance in tree-type #concatenatedcodes, allowing one to implement non-Clifford gates fault-tolerantly on the holographic boundary. We also demonstrate that these codes allow for high erasure thresholds under a suitable heterogeneous combination of specific seed codes. Compared to previous concatenated codes, heterogeneous holographic codes achieve large overhead savings in physical qubits, e.g., a 21.8% reduction for a two-layer Steane/quantum Reed-Muller combination. Unlike standard concatenated codes, we establish that the new codes can encode more than a single logical qubit per code block by applying ``#blackhole'' deformations with tunable rate and distance, while possessing fully addressable, universal fault-tolerant gate sets. Therefore, our work strengthens the case for the utility of holographic quantum codes for practical quantum computing.

We are currently offering several multi-year postdoctoral research positions to highly motivated and well-qualified researchers who intend to enhance their career in #quantuminformation science or in quantum #manybodyphysics. The positions on the E13 and E14 level are funded by an @ERC_Research Advanced Grant, and are also connected to other frameworks and schemes such as #BerlinQuantum and the European @QuantumFlagship. We are a highly research-active and visible team in quantum information science and the study of complex quantum systems, with a culture of open discussion, creative interdisciplinary thought and substantial international collaborations. We are conceptually minded and work with the rigor of mathematical physics, but are at the same time often pragmatically motivated and guided by the protocol, the phenomenon, the application, or the experimental implementation. physik.fu-berlin.de/en/einri… For an overview over recent publications, see this link: physik.fu-berlin.de/en/einri…. Potential research topics include the following: • #Quantumcomputing and #quantumalgorithms. • Foundations of #quantuminformation science. • Near-term quantum computing #NISQ. • #Quantumerrorcorrection. • #Tensornetwork methods. • #Quantumphases of matter. Applicants must have demonstrated excellent research accomplishments in the past. Candidates should hold a PhD degree in physics, mathematics or computer science. Interested candidates are invited to submit • a letter indicating their main research interests. • A detailed curriculum vitae. • A list of publications. • The electronic contact details of three referees. All applications should be sent in electronic form to BOTH [email protected] and [email protected], with the keyword "Postdoc2024" in the subject line. For inquiries, please send a message to [email protected]. The start date is flexible.