Within the seminar, students give talks on current topics in condensed matter physics. The seminar aims to give a closer look at new developments in condensed matter physics and to show how these developments can be transferred into applications. The seminar focuses on spin electronics, spin dynamics, solid-state quantum information processing, the physics of solid-state nanostructures, and high temperature superconductivity. These topics are in the focus of several research projects of WMI and collaborative research programs in the Munich area (e.g. the Excellence Cluster "Munich Center for Quantum Science and Technology (MCQST)", the Munich Quantum Valley e.V., as well as several BMBF and EU projects).

The seminar is relevant for the special courses on Quantum Science and Technology, Superconductivity and Low Temperature Physics as well as on Magnetism and Spintronics. It is suitable for bachelor students in the 5th semester or higher and for master students.

Schedule

List of open topics for seminar talks in SS 2024:

1. All-electrical skyrmionic magnetic tunnel junction (Shaohai Chen et al., Nature 627, 522-527 (2024))

2. Room-temperature quantum optomechanics using an ultralow noise cavity (G. Huang et al., Nature 626 512-517 (2024))

3. Quantum spin nematic phase in a square-lattice iridate (Hoon Kim et al., Nature 625 264-269 (2024))

4. Finite-momentum Cooper pairing in proximitized altermagnets (Song-Bo Zhang et al., Nature Commun. 15, 1801 (2024))

5. Observation and control of hybrid spin-wave–Meissner-current transport modes (M. Borst et al., Science 382 430-434 (2023))

6. Evidence for chiral supercurrent in quantum Hall Josephson junctions (H. Vignaud et al., Nature 624 545-550 (2023))

7. Spinon Heat Transport in the Three-Dimensional Quantum Magnet PbCuTe2O6 (Xiaochen Hong et al., Phys. Rev. Lett. 131, 256701 (2023))

8. Exploring large-scale entanglement in quantum simulation (M.K. Joshi et al., Nature 624 539-544 (2023))

9. Quantum oscillations of the quasiparticle lifetime in a metal (N. Huber et al., Nature 621, 276-281 (2023))

10. A quantum electromechanical interface for long-lived phonons (A. Bozkurt et al., Nature Physics 19 1326-1332 (2023))

11. Quantum advantage in microwave quantum radar (R. Assouly et al., Nature Physics 19, 1418-1422 (2023))

12. Microwave Fluorescence Detection of Spin Echoes (E. Billaud et al., Phys. Rev. Lett. 131, 100804 (2023))

13. Chiral phonons in quartz probed by X-rays (H. Ueda et al., Nature 618, 946-950 (2023))

14. Fluctuation-enhanced phonon magnetic moments in a polar antiferromagnet (F. Wu et al., Nature Physics (2023))

15. Time-domain observation of ballistic orbital-angular-momentum currents with giant relaxation length in tungsten (T.S. Seifert et al., Nature Nanotechnology (2023))

16. Observation of Spin-Wave Moiré Edge and Cavity Modes in Twisted Magnetic Lattices (Hanchen Wang et al., Phys. Rev. X 13, 021016 (2023))

17. Proximity superconductivity in atom-by-atom crafted quantum dots (L. Schneider et al., Nature 621, 60-65 (2023))

18. Indistinguishable telecom band photons from a single Er ion in the solid state (S. Ourari et al., Nature 620, 977-981 (2023))

19. Room-temperature magnetoresistance in an all-antiferromagnetic tunnel junction (Peixin Qin et al., Nature 613, 485 (2023))

20. Millisecond Coherence in a Superconducting Qubit (Aaron Somoroff et al., Phys. Rev. Lett. 130, 267001 (2023))

21. Beating the break-even point with a discrete-variable-encoded logical qubit (Zhongchu Ni et al., Nature 616, 56-60 (2023))

22. Macroscopic Quantum Test with Bulk Acoustic Wave Resonators (Björn Schrinski et al., Phys. Rev. Lett. 130, 133604 (2023))

23. On-demand directional microwave photon emission using waveguide quantum electrodynamics (Bharath Kannan et al., Nature Physics 19, 394 (2023))

24. Nonlinear multi-frequency phonon lasers with active levitated optomechanics (Tengfang Kuang et al., Nature Physics 19, 414 (2023))

25. Giant spin polarization and a pair of antiparallel spins in a chiral superconductor (R. Nakajima et al., Nature 613, 479 (2023))

Within the Colloquium on Solid State Physics international experts present talks on recent important developments in the fields of solid state physics and solid-state-based quantum systems.

For the announcement of talks, see: https://www.wmi.badw.de/teaching/colloquium-on-solid-state-physics

Content

Within the seminar Superconducting Quantum Circuits, students present state-of-the-art developments in modern quantum technology with superconducting quantum circuits. In this field, funamental research in academia has meanwhile triggered highly dynamical activities from established large corporations (Google, IBM, Intel etc.) and ambitious startups (Rigetti, IQM, HQS etc.). In particular, superconducting quantum circuits belong to the few prime candidates for a scalable quantum computer.

Time/Place

12:00 - 14:00h, WMI-Seminarroom, room 143

Schedule

List of open topics for seminar talks in SS 2024:

Quantum Computing:

1. Logical quantum processor based on reconfigurable atom arrays    Nature    Lukin (MIT),  https://www.nature.com/articles/s41586-023-06927-3
2. Encoding a magic state with beyond break-even fidelity, Nature, IBM,    https://www.nature.com/articles/s41586-023-06846-3
3. Efficient long-range entanglement using dynamic circuits (IBM),    https://arxiv.org/abs/2308.13065
4. Beating the break-even point with a discrete-variable-encoded logical qubit (Yu),    https://doi.org/10.1038/s41586-023-05784-4

Superconducting Circuits

1. Generation of genuine entanglement up to 51 superconducting qubits (Pan, Hefei),    https://www.nature.com/articles/s41586-023-06195-1
2. Microwave Photon-Number Amplification   (Hofheinz, Grenoble/Sherbrooke),    https://journals.aps.org/prx/abstract/10.1103/PhysRevX.14.011011,
3. Dual-rail encoding with superconducting cavities (Schoelkopf, Yale),    https://www.pnas.org/doi/abs/10.1073/pnas.2221736120
4. High-Fidelity, Frequency-Flexible Two-Qubit Fluxonium Gates with a Transmon Coupler (Oliver, MIT),    https://journals.aps.org/prx/abstract/10.1103/PhysRevX.13.031035
5. Transmon qubit readout fidelity at the threshold for quantum error correction without a quantum-limited amplifier (Bylander, Chalmers),    https://www.nature.com/articles/s41534-023-00689-6
6. Two-level system hyperpolarization using a quantum Szilard engine (Pop, KIT),  https://www.nature.com/articles/s41567-023-02082-8
7. Realizing a deep reinforcement learning agent for real-time quantum feedback   (Marquadt, Wallraff, Eichler, ETH),    https://www.nature.com/articles/s41467-023-42901-3
8. Cloaking a qubit in a cavity  (Huard/ Blais , Lyon/Sherbrooke),     https://www.nature.com/articles/s41467-023-42060-5
9. Bidirectional Multiphoton Communication between Remote Superconducting Nodes (Cleland, Chicago),    https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.132.047001
10. Optimizing Resource Efficiencies for Scalable Full-Stack Quantum Computers (Auffeves), https://journals.aps.org/prxquantum/abstract/10.1103/PRXQuantum.4.040319?utm_source=email&utm_medium=email&utm_campaign=prxquantum-alert
11. On-demand directional microwave photon emission using waveguide quantum electrodynamics (Oliver, MIT), https://www.nature.com/articles/s41567-022-01869-5
12. Millisecond Coherence in a Superconducting Qubit  (Manucharyan),     https://doi.org/10.1103/PhysRevLett.130.267001
13. Quantum Simulation of Topological Zero Modes on a 41-Qubit Superconducting Processor (Heng Fan, Hefei), https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.131.080401

Quantum Sensing

1. Correlation Spectroscopy with Multiqubit-Enhanced Phase Estimation (Roos, Blatt , Innsbruck), https://journals.aps.org/prx/abstract/10.1103/PhysRevX.14.011033
2. High-sensitivity AC-charge detection with a MHz-frequency fluxonium qubit (Deleglise, CNRS), https://journals.aps.org/prx/abstract/10.1103/PhysRevX.14.011007
3. Quantum advantage in microwave quantum radar (Huard),    https://doi.org/10.1038/s41567-023-02113-4

Hybrid Quantum Systems

1. Quantum-enabled millimetre wave to optical transduction using neutral atoms (Schuster, Simon, Stanford), https://www.nature.com/articles/s41586-023-05740-2
2. Single electron-spin-resonance detection by microwave photon counting (Flurin, Bertet, CEA Saclay)    https://www.nature.com/articles/s41586-023-06097-2

Theory

1. Charging Effects in the Inductively Shunted Josephson Junction (J. Koch, Yale), https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.103.217004

2. Efficient high-fidelity flying qubit shaping (Burkard, Konstanz), https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.6.013150

3. Multimode-cavity picture of non-Markovian waveguide QED (Ciccarello, Palermo), https://arxiv.org/abs/2403.07110

4. Reminiscence of Classical Chaos in Driven Transmons (Blais, Sherbrooke), https://journals.aps.org/prxquantum/abstract/10.1103/PRXQuantum.4.020312

Topical directions of the seminar:

• Foundations and applications of superconducting quantum circuits in quantum computing, quantum simulation, quantum communication, quantum sensing, and quantum metrology.
• Superconducting quantum technology: Resonators, waveguides, quantum bits, couplers, quantum-limited amplifiers, quantum processors, quantum error correction etc.
• State-of-the-art fabrication and measurement tachniques for superconducting quantum circuits.
• Investigation of the fundamental light-matter interaction "on a chip" using superconducting quantum circuits.
• Quantum information theoretical concepts: Entanglement, quantum gates, quantum algorithms, quantum memories, quantum measurements etc.
• The coupling of nanomechanical systems and spin ensembles to superconducting circuits.
• Challenges: longer quantum coherence, higher gate fidelities, scalability to a large number of qubits etc.
• Latest developments on the strive towards quantum advantages over conventional technology
• Propagating quantum microwaves emitted by superconducting circuits: quantum ressources, quantum microwave communication, quantum radar

You will be supported in the preparation of your talks from the research groups on superconducting quantum circuits, propagating quantum microwaves, and nanomechanics at the Walther-Meißner-Institute.

Learning Outcome:

After the successful completion of the module the students are able

• To prepare presentation slides on a scientific topic and to clearly present a topical research field within a scientific talk.
• To discuss on a state-of-the-art research field in a scientific way.
• To analyze and assess the latest development in quantum scinece and technology with superconducting circuits.
• To understand and explain the foundations of superconducting quantum systems and technology.
• To understand the foundations and the state of the art in quantum computing, quantum simulation, quantum communication, quantum sensing, and quantum metrology with supercondcuting circuits
• To understand the foundations and the state of the art in nanomechnical systems and spin ensembles

Preconditions:

Basic knowledge of condensed matter physics, foundations of quantum mechanics

Content

This module provides a detailed discussion of the fascinating properties of quantum liquids, mesoscopic solid state systems (nanostructures) as well as experimental low temperature techniques. The following specific topics will be addressed:

• Bose-Einstein condensation
• Superfluid Helium-3 and Helium-4
• Quantum interference effects in mesoscopic metallic systems (weak localization, universal conductance fluctuations, etc.)
• Coulomb blockade and single electron transistors
• Generation of low temperatures
• Measurement of low temperatures

Learning Outcome

After successful completion of the module the students are able to:

• to identify the fundamental differences between classical and quantum liquids
• to describe the transition from a classical to a quantum liquid by reducing the temperature
• to explain the relevance of quantum statistics (bosons vs. fermions) for the general behavior of quantum liquids
• to derive the expression of the Bose-Einstein condensation temperature
• to list and explain the basic properties of superfluid He-4 and He-3
• to list and explain the characteristic length and time scales playing an important role for charge transport in mesoscopic conductors as well as to apply them for the description of charge transport phenomena
• to describe the impact of quantum interference effects in the charge transport in mesoscopic systems and to explain phenomena such as universal conductance fluctuations and weak localization
• to list the most relevant methods for the generation of low temperatures as well as to describe and explain their physical foundations

Preconditions

Basic knowledge on condensed matter physics and quantum mechanics.

Within the Walther-Meißner-Seminar national and international experts present talks on current research related to the research topics of the Walther-Meißner-Institute such as quantum information systems, superconducting qubits and quantum circuits, magnetism & spintronics, quantum microwave communication and sensing or the fabrication technology for superconducting and magnetic devices.

For the announcement of talks, see: https://www.wmi.badw.de/teaching/walther-meissner-seminar