The Quantum Paper Club is organized by students for students. Its goal is to expose the students interested in Quantum Engineering to the research done in the field. More than this, it is a formidable platform to practice public scientific speaking.
The Quantum Paper Club usually takes place on Thursdays at 17:45 in HIT H42. If you would like to present, please contact Carlo Schmitt del Brenna (), Susan Filisetti () or Erenay Karacan ().
The Quantum Paper Club has concluded for the current semester. We will be back again next semester.
Past Talks
-
Insights from Quantum Foundations into Black Holes
22.05.2025Prof. Renato Renner
This talk is a collaboration between Theory Talks and Quantum Paper Club!Black holes offer a testing ground for the interplay between General Relativity and quantum theory, exemplified by phenomena such as Hawking radiation. Yet, this interplay gives rise to deep puzzles, notably the “firewall paradox”, in which the combined predictions of an infalling observer and…
-
Understanding the coherence properties of HBARs in the classical and quantum regimes
15.05.2025Raquel García Bellés
High overtone bulk acoustic wave resonators (HBARs) have been successfully integrated with superconducting qubits into hybrid quantum systems with many applications in quantum information technologies. Their success strongly relies on the excellent coherence properties of the mechanical modes. Nevertheless, a full understanding of the limiting loss mechanisms affecting multimode HBAR devices is still missing.In this…
-
Introduction to quantum LDPC codes – constructions, decoding and logical gates
08.05.2025Anqi Gong
Quantum low-density parity-check (qLDPC) codes have recently attracted significant interest due to their high encoding rates and good distance properties, while still requiring only low-weight stabilizer measurements. In this introductory talk, I will present leading constructions for qLDPC codes, such as the hypergraph-product and lift-product methods, and briefly discuss how the resulting codes can be realized on actual…
-
Quantum pseudoresources imply cryptography
17.04.2025Álvaro Yángüez
While one-way functions (OWFs) serve as the minimal assumption for computational cryptography in the classical setting, in quantum cryptography, we have even weaker cryptographic assumptions such as pseudo-random states, and EFI pairs, among others. Moreover, the minimal assumption for computational quantum cryptography remains an open question. Recently, it has been shown that pseudoentanglement is necessary…
-
Random Amplification with Bell Tests
03.04.2025Prof. Dr. Ramona Wolf
Randomness is a regular part of our (more or less) daily lives: from drawing lottery numbers to running computer simulations and the security of cryptographic schemes, various applications rely on random numbers. But does true randomness actually exist? If so, can we create truly random numbers in our labs? Luckily, the intrinsic randomness of quantum…
-
Quantum Error Correction with Superconducting Circuits
27.03.2025Nathan Lacroix
This talk will be followed by an apero! Quantum computing has the potential to solve problems that are intractable for the most powerful supercomputers. However, quantum computers must overcome errors arising from decoherence and imperfect control to realize this potential. Quantum error correction provides a path to bridge the gap between physical error rates and…
-
Deterministic generation of two-dimensional multi-photon cluster states
20.03.2025Alonso Hernández-Antón
Multipartite entangled states are a key resource for robust quantum communication, measurement-based quantum computing and quantum metrology. We present device capable of emitting large-scale entangled microwave photonic states with a two dimensional entanglement structure. The device consists of a pair of coupled superconducting transmon qubits which are each tuneably coupled to a common output waveguide.…
-
Quantum Information Processing with GKP Qubits
13.03.2025Florence Berterottière
Motional modes of a trapped ion are naturally accessible harmonic oscillators.Gottesman-Kitaev-Preskill (GKP) states, also known as grid states, can encode a logical qubit in a quantum harmonic oscillator. In our experiment, we use quantum error correction (de Neeve et al., 2022) to stabilize GKP states of the motion of a trapped ion.This talk will underline…
-
Quantum Correlations in Spacetime
06.03.2025Carla Ferradini
Information-theoretic quantities, such as the mutual information, are defined to measure correlations between physical systems. In classical information theory, describing systems as random variables, these quantities are defined independently of the spacetime location of the systems. However, in quantum information theory, where systems are associated with density operators on a Hilbert space, only a definition…
-
Hamiltonian Simulation with Quantum Signal Processing
27.02.2025Erenay Karacan
Hamiltonian simulation is a domain where quantum computers have the potential to outperform their classical counterparts and is the focal point of current research at many quantum companies, to showcase the performance of their latest quantum computers. In this talk, we’ll discuss a powerful approach called “Quantum Signal Processing (QSP)”- that unifies all quantum algorithms…
-
Searching for new physics by measuring isotope-shifts and parity violation in trapped ions
17.12.2024Diana Aude Craik
In this talk I will discuss recent results of a search, performed in the TIQI group, for a new fundamental force between the neutron and the electron using a technique known as isotope-shift spectroscopy. I will then outline a new endeavor I’m starting at ETH to perform the most stringent test to date of the…
-
Superfluorescence in Lead Halide Perovskite Nanocrystals
05.12.2024Thilo Stöferle
Fully inorganic cesium lead halide perovskite nanocrystals have emerged as an interesting optoelectronic material due to several extraordinary properties. They exhibit giant oscillator strength and long dephasing time at cryogenic temperature as well as low inhomogeneous energetic broadening, which makes them ideally suited to explore settings that exploit their exceptionally strong intrinsic light-matter coupling and…
-
In situ observation of density-wave ordering in strongly interacting Fermi gases
28.11.2024Tabea Bühler
Quantum gas experiments provide a unique opportunity to create and study complex quantum many-body systems. A high degree of controllability allows to manipulate different components of the Hamiltonian and to study their influence on the emergent physics. This contributes to the understanding of many-body phenomena, especially in situations where the strong correlations between particles make…
-
Hardware-friendly Implementations of Quantum Variational Algorithms
21.11.2024Sabina Dragoi
Since nature is quantum mechanical, corresponding models have a state space that grows exponentially with problem size. Quantum computers were thus first proposed as a platform to solve such hard problems in physics and chemistry. Despite the progress of quantum, current error rates remain a major obstacle. In this project we develop and experimentally test…
-
A Quantitative Approach to Vacuum Design
14.11.2024Marius Gächte
The growing interest in quantum computing using ultracold gases (Bluvstein et al., 2024; Manetsch et al., 2024) has sparked increased focus on the transition from routinely achieved ultra-high vacuum (UHV) to the regime of extremely high vacuum (XHV, < 1e-11 mbar).This shift is critical, as collisions between trapped atoms and background gases quickly become the…
-
Assembling quantum matter one atom at a time
05.11.2024Antoine Browaeys
Over the last twenty years, physicists have learned to manipulate individual quantum objects: atoms, ions, molecules, quantum circuits, electronic spins… It is now possible to build “atom by atom” a synthetic quantum matter. By controlling the interactions between atoms, one can study the properties of these elementary many-body systems: quantum magnetism, transport of excitations, superconductivity……
-
Assessing the Correctability of a Quantum Memory
31.10.2024Yanis Le Fur
Neutral atoms are promising building blocks for quantum computing due to their scalability, flexibility and high-fidelity operations. However, they are susceptible to various noise sources, necessitating robust error correction. This study uses multi-qubit error-correcting codes to mitigate these errors. First, we decompose the noise sources affecting neutral atoms into Pauli noise components to establish an…
-
Quantum sensing with a transmon qubit
24.10.2024Rémi Truong
Transmon qubits are widely studied due to their non-linear properties, which are effective down to the single-photon level. Their anharmonicity is particularly useful for quantum information processing purposes. In this context, we are interested in another non-linearity: four-wave mixing. By combining this with a clever dissipation bath, we can create a single-microwave-photon detector (SMPD), which…
-
QKAN: Quantum Kolmogorov-Arnold Networks
17.10.2024Peter Ivashkov
The field of quantum machine learning persistently explores how learning models can take advantage of quantum implementations. Recently, a new neural network architecture, called Kolmogorov-Arnold Networks (KAN), has emerged, inspired by the Kolmogorov-Arnold theorem. We designed a quantum version of KAN (QKAN) by combining parameterized quantum circuits with powerful algorithmic subroutines. In this talk, I…
-
Mitigating losses in superconducting qubits
10.10.2024Dominic Hagmann
Superconducting Circuits are a promising platform to implement fault-tolerant quantum computers. To achieve low enough error rates to implement logical qubits and run useful algorithms, it is essential that the quantum information stored in the qubits can be retained for sufficiently long times. Material losses are currently limiting the life-times of superconducting qubits.In this talk…
-
Stabilization of cat-states in trapped ion systems outside the Lamb-Dicke regime
03.10.2024Matteo Simoni
Schrodinger’s cat qubits are a promising candidate for bosonic error correction and have been the subject of extensive theoretical and experimental investigation. We introduce a new paradigm to stabilize cat-like states using interfering gain and loss processes with different nonlinear dependence on the energy of the oscillator. Where these competing processes are equal in strength,…
-
Manipulating molecules in Rydberg states for physical Chemistry
26.09.2024Raphaël Hahn
Cold molecules are now at the forefront of research, allowing to explore cold chemistry, astrophysics, quantum computing and even fundamental physics. Extensions of methods used to cool atoms are now being applied to more and more complex molecules. Reaching cold temperatures (< 10 K) allows for example the study of quantum effects in chemical reactions.I…
-
Towards spin-optomechanics with nitrogen-vacancy centers in diamond
19.09.2024Teresa Pfau
A single spin, as found in the nitrogen-vacancy (NV) center, is a purely quantum system, whereas our 1×1 mm membranes behave like classical resonators, vibrating similarly to trampolines. Our aim is to bridge these two systems by investigating the spin-mechanical coupling between the magnetic states of a single NV center and the motion of a…
-
Quantum Matter under the Microscope
23.05.2024Julian Léonard
Neutral atoms are nature’s perfect qubits: they are all identical, and our precise knowledge of their properties allows us to control them at will. Cooling and trapping many atoms offers the unique opportunity to experimentally address outstanding problems in many-body quantum physics. Quantum gas microscopy brings this effort to the ultimate level of single particle…
-
Tensor Network Algorithms for Quantum Chemistry
16.05.2024Nina Glaser
High-accuracy quantum chemical calculations are commonly limited to relatively small molecules due to the exponential scaling of the computational cost with the number of involved particles. By leveraging powerful tensor decomposition-based approaches, tensor network algorithms are continuously expanding the scope of wave function-based molecular simulation methods. While tensor network-based methods such as the density matrix…
-
Security Proof of QKD Protocols via Entropic Uncertainty Relations
02.05.2024Jan Obermeier
The field of Quantum Key Distribution (QKD) has attracted a lot of attention as one of the quantum technologies that not only addresses one of the most pressing problems in secret communication, but has also shown promising progress on the implementation side. A major advantage of QKD protocols is their provable security. This talk will…
-
Optical levitation on chip
24.04.2024Pedro Rosso
Levitation in vacuum has evolved into a versatile technique which has already benefited diverse scientific directions, from force sensing and thermodynamics to material science and chemistry. It also holds great promises of advancing the study of quantum mechanics in the unexplored macroscopic regime. While most current levitation platforms are complex and bulky, miniaturization is sought…
-
Engineering New Doppler Limits
18.04.2024Wojciech Adamczyk
When you want to trap neutral atoms in optical tweezers you better be cold. And when I say cold I don’t mean dilution fridge cold. I mean 10 times colder. To reach such temperatures we conventionally use laser cooling, which brings us to the doppler temperature proportional to the transition linewidth. But what if the…
-
Entropy Spectroscopy of a Bilayer Graphene Quantum Dot
11.04.2024Christoph Adam
Bilayer graphene (BLG) has emerged as a promising platform for hosting qubits within 2D materials. By encapsulating it in a dielectric and applying gating techniques, one can electrostatically confine individual charge carriers, both electrons and holes, and thus obtain what is called a quantum dot (QD). Charge detection schemes allow us study the quantum properties…
-
Soft information decoding: Are we overlooking measurement details in quantum error correction?
27.03.2024Maurice D. Hanisch
Quantum computers can provide asymptotically faster computation times than their classical counterparts in specific applications. However, to outperform the classical computers we have today, we need large-scale, fault-tolerant devices. Quantum error correction (QEC) is considered one of the most promising ways of achieving this milestone. However, much work is still needed to improve both the…
-
Supersolidity in ultracold quantum gases: the simultaneous crystalline and superfluid nature of dipolar atoms
21.03.2024Francesca Ferlaino
Quantum physics frequently gives rise to conceptual paradoxes that defy our classical intuition. In many-body quantum systems, interactions are key, especially when they dominate over kinetic energy. Their form and strength crucially define the existing strongly-correlated quantum phases of matter and dictate phenomena beyond the classical regime. Dipolar interactions, particularly relevant in strongly magnetic atoms,…
-
Performance constraints of NISQ quantum algorithms and their mitigation with 3D-integrated superconducting quantum devices
14.03.2024Kieran Dalton
In recent years, the excitement around NISQ algorithms has diminished, partly due to the performance limitations of existing quantum computers. Devices with more qubits and lower error rates are necessary to realize the potential of quantum computing. In the first half of this talk, I will illustrate these performance limitations with the example of the…
-
Two-dimensional terahertz spectroscopy in complex matter systems
07.03.2024Alex Gomez Salvador
Two-dimensional terahertz spectroscopy (2DTS), a terahertz analogue of nuclear magnetic resonance, stands as a novel technique poised to address numerous open questions in complex condensed matter systems. The conventional theoretical framework, widely used for interpreting multidimensional spectra of discrete quantum-level systems, falls short in capturing the continua of collective excitations in strongly correlated materials, and…
-
Single Molecular Ions for Precision Spectroscopy and Molecular Quantum Technologies
29.02.2024Richard Karl
Within the rich energy level structure of molecules, transitions with advantageous properties for precision studies and molecular quantum technologies can be found [1]. However, in the absence of closed cycling transitions and frequencies ranging from MHz for hyperfine transitions to GHz in rotational transitions and THz in ro-vibrational transitions [2], efficient cooling of translational degrees…
-
Multi-Qubit Gates for Bosonic Logical Qubits
22.02.2024Ivan Rojkov
Bosonic codes comprise a paradigm for quantum computing and quantum error correction where quantum information is encoded in continuous degrees of freedom such as modes of radiation or motion. In particular, Gottesman-Kitaev-Preskill (GKP) codes [1] are promising candidates for bosonic quantum information processing, in which quantum error correction has recently been demonstrated both in superconducting…
-
Quantum Control of a Cat-Qubit With Bit-Flip Times Exceeding Ten Seconds
14.12.2023Dr. Ronan Gautier
Cat qubits encode quantum information in the metastable states of a quantum harmonic oscillator, offering robust protection to bit-flip errors. This talk presents a cat qubit with bit-flip durations over ten seconds, greatly surpassing both previous implementations of the qubit and the lifetime of its components. This is achieved through a new quantum tomography method…
-
Precision Spectroscopy in the Helium Atom
07.12.2023Gloria Clausen
Few electron atoms and molecules such as H, He(+), H2(+) and He2(+) are simple enough for their properties to be calculated exactly from first principles (QM, QED). Comparison with precision-spectroscopic data enables one to test the calculations, reduce the uncertainties of fundamental constants and determine particle properties (e.g. α, mp/me and RH) or may allow…
-
Cryptography and Quantum Key Distribution
30.11.2023Riccardo Cicchetti
Fault-tolerant Quantum Computers threaten the current cryptographic mechanisms on which the security of our day-to-day communication relies. Extensive research is conducted to find, so-called, Post-Quantum cryptographic primitives. In other words, cryptographic tools that should be hard to break for a quantum computer at scale. However, the security of these solutions is still reliant on a…
-
Practical Quantum Algorithms
23.11.2023Guglielmo Mazzola
In this talk, I will delve into obvious, less obvious, and subtle challenges, as well as good practices for developing quantum algorithms in pursuit of practical quantum advantage. This is defined as achieving a quantum algorithm faster than the best possible classical algorithm for a genuinely relevant problem in science and technology. I will place…
-
Quantum Causal Models
16.11.2023Carla Ferradini
Inferring cause and effect relations from observed correlations is a fundamental aspect of science. A causal modelling framework has been formulated to describe correlations among classical random variables arising from a causal structure and has found diverse applications in machine learning, economics, and clinical trials. However, experimental violations of Bell inequalities demonstrate the inadequacy of…
-
Developing Superconducting Bosonic Qubits in a Planar Low-Loss Architecture
09.11.2023Alessandro Bruno
Emerging quantum technologies, including quantum computers and quantum simulators, crucially rely on high-quality qubits. However, even state-of-the-art qubits are susceptible to errors caused by noise processes, which impose constraints on the device performance. Standard approaches to quantum error correction aim to suppress these errors by introducing redundancy based on coupling a large number of qubits,…
-
Performance Constraints of NISQ Quantum Algorithms and their Mitigation with 3D-Integrated Superconducting Quantum Devices
26.10.2023Kieran Dalton
In recent years, the excitement around NISQ algorithms has diminished, partly due to the performance limitations of existing quantum computers. Devices with more qubits and lower error rates are necessary to realize the potential of quantum computing. In the first half of this talk, I will illustrate these performance limitations with the example of the…
-
Quantum Imaging of Nanoscale Electronic Transport in Graphene with Nitrogen-Vacancy Centers in Diamond
19.10.2023Chaoxin Ding
Nitrogen-vacancy (NV) center in diamond, a spin qubit with long coherence time up to room temperature, has been demonstrated as a powerful tool for various quantum technologies, especially for quantum sensing. In this presentation, I will show its promising application for investigating nanoscale electronic transport phenomena in condensed matter physics, specifically, hydrodynamic flow in graphene.…
-
Spin- and Momentum-Correlated Atom Pairs via Photon Exchange and Vacuum Fluctuations
12.10.2023Fabian Finger
Mechanisms generating correlated pairs of particles are at the core of diverse fields of physics such as Hawking radiation, phonon-mediated superconductivity or spontaneous parametric down-conversion. Similar approaches have been explored with ultracold atoms to correlate massive particles in various degrees of freedom. We use a Bose-Einstein condensate coupled to a high-finesse optical cavity to generate…
-
Integrated Optics for Scalable Trapped-Ion Quantum Computing
05.10.2023Gillenhaal Beck
Trapped ions provide a promising platform for large scale quantum computing. A crucial element of this scalability will be the integration of laser light into the trapping chips themselves. In this talk, I will first provide a brief overview of trapped-ion systems and the path to scalability. The many benefits provided by integrated photonics will…
-
Photonics Building Blocks in Alumina for Controlling Trapped Ions
28.09.2023Sophie Cavallini
Photonic integrated circuits (PIC) can be exploited to control trapped ions more robustly than free-space optics. Most of the work done in this area used silicon nitride (Si3N4), however, it is incompatible with UV wavelengths. Instead, aluminium oxide (Al2O3) proves to be a suitable waveguide material. This project focuses on designing and optimizing several integrated…
-
Single-Photons, Entangled Photon Pairs & Optimal Quantum Cloning of Qubits
25.05.2023Nicolas Gisin
Quantum physics has many applications today, many techniques have been developed and are now used in various fields. However, going back to the foundations, there are many interesting and still unresolved questions. This week, Nicolas Gisin will talk about the single photon, how to define it and how far it can travel if you want…
-
Atomistic DFT Simulation of Scaled 3nm FinFET & 22nm FDSOI CMOS Quantum Dot Devices
17.05.2023Vivek Dhande
Current production FinFET and FDSOI CMOS technologies are suitable for large-scale, high-density quantum processor (QP) and readout control electronics. Due to layout manufacturability restrictions, that limit the types of qubit arrays and gates that can be implemented, the top gate pitch is too large for strong tunnel coupling between adjacent quantum dots (QDs), limiting the…
-
A Quantum Information View on Black Holes
11.05.2023Giulia Mazzola
A major discovery by Hawking was that the interplay between general relativity and quantum theory leads to the prediction that black holes must radiate. In Hawking’s original calculation however, the black hole radiation was found to be of thermal character, thus leaving behind a mixed state describing the radiation as soon as the black hole…
-
Schrödinger Cat States in a 16-microgram Mechanical Oscillator
04.05.2023Marius Bild
While the principle of superposition in quantum physics is routinely validated for microscopic systems, it is still unclear why we do not observe macroscopic objects to be in superpositions of states that can be distinguished by some classical property. I will present our experiments, that harness the resonant Jaynes-Cummings interaction between a high overtone resonator…
-
Motional Squeezing for Trapped Ion Transport and Separation
27.04.2023Dario Scheiwiller
One of the (many) challenges in scalable quantum computing with trapped ions is the transport of the ions. The transport of the ions needs to be done while avoiding the arch-enemy of ion-trappers: motional heating. In my talk we’ll discuss a recent paper by Sutherland et al. that explores a new protocol of ion transport,…
-
From Machine Learning to Computational Quantum Physics
06.04.2023Filippo Vicentini
Machine-learning techniques that originated in several domains of “Artificial Intelligence”, are increasingly being applied to tackle problems in physical sciences. Applications range from experimental fields, where ML has been leveraged to more efficiently carry out measurements, inhibit noise or design structures, to computational and theoretical physics. In particular, a recent breakthrough showed that several numerical…
-
Quantum Control of Trapped Ions with Integrated Photonics
30.03.2023Alfredo Ricci Vásquez
Scaling up trapped ion quantum information processors requires high fidelity control over many ions. One way of achieving such control is by using a trap with multiple zones, each zone holding few ions which can be manipulated with high fidelity. Operations between the ions are achieved by means of transporting the ions across zones. Although…
-
Realizing Quantum Convolutional Neural Networks on a Superconducting Quantum Processor to Recognize Quantum Phases
23.03.2023Johannes Herrmann
Quantum computing crucially relies on the ability to efficiently characterize the quantum states output by quantum hardware. Conventional methods which probe these states through direct measurements and classically computed correlations become computationally expensive when increasing the system size. Quantum neural networks tailored to recognize specific features of quantum states by combining unitary operations, measurements and…
-
An Intuitive Approach to Analogue Gravity in Bose-Einstein Condensates
16.03.2023Sébastien Garmier
An analogue gravity model is a physical system in flat spacetime with wave propagation behaving like the propagation of a scalar field of mass m in some curved spacetime. In the first part, we review analogue gravity models with wave propagation governed by a Lagrangian. In this context we propose a novel and more pedagogical…
-
Quantum Knitting for Dummies
09.03.2023James O’Sullivan
Multidimensional tensor-network states, such as cluster states, are a key resource for quantum communication and measurement-based quantum computing. Recently, cluster states have been generated both in the microwave and optical regime but the generation of large-scale 2D cluster states in discrete-variable systems remains challenging. We present a superconducting device to enable the generation of two-dimensional…
-
Quantum Computing Applications and the Measurement Problem
02.03.2023Laurin Fischer
With digital quantum computers reaching the scale of ~100 qubits and ever-increasing gate fidelities and coherence times, potential applications of quantum computing can now be explored on noisy hardware. This talk gives an overview of such applications with a particular focus on algorithms for quantum chemistry. On noisy hardware, i.e., before fault-tolerance, the depth of…
| Meeting date | Topic | Presenter | Abstract | Link to reference |
|---|---|---|---|---|
| 26.04.2022 | The impact of quantum mechanics on philosophy | Lev Vaidman (Professor @ Tel Aviv University) | The uncertainty principle and Bell-type correlations led to a dramatic change in the philosophy of science. Today we are ready to accept indeterminism and some kind of action at a distance. I will argue that this move is not necessary and maybe mistaken. Accepting the existence of multiple parallel worlds allows restoring determinism and avoiding action at a distance. The issue of probability in the many-worlds framework, however, requires introducing a novel element in science. Warning: I plan to split the world during the talk! | |
| 19.04.2022 | Dynamic generation of entangled electrons in a Cooper pair splitter | Fredrik Brange (PostDoc @ Aalto University) | Cooper pair splitters are promising candidates for generating spin-entangled electrons. However, the splitting of Cooper pairs is a random and noisy process, which hinders further synchronized operations on the entangled electrons. To circumvent this problem, we propose and analyze a dynamic Cooper pair splitter that produces a noiseless and regular flow of spin-entangled electrons. The Cooper pair splitter is based on a superconductor coupled to quantum dots, whose energy levels are tuned in and out of resonance to control the splitting process. We identify the optimal operating conditions for which exactly one Cooper pair is split per period of the external drive and the flow of entangled electrons becomes noiseless. To characterize the regularity of the Cooper pair splitter in the time domain, we analyze the g(2) function of the output currents and the distribution of waiting times between split Cooper pairs. Our proposal is feasible using current technology, and it paves the way for dynamic quantum information processing with spin-entangled electrons. | Link |
| 12.04.2022 | Introduction to dissipation engineering | Elias Zapusek (PhD @ ETH TIQI) | Dissipation arises in quantum systems due to interaction with environment. In unitary quantum information processing dissipation is primarily considered as a source of noise. However, we can also use controlled dissipation to manipulate quantum systems. Starting from the most well-known example optical pumping and moving on to more complex schemes I will give a brief introduction to the field of dissipation engineering. | Link |
| 05.04.2022 | Saving the cat: From open quantum systems to bosonic quantum error correction | David Schlegel (PhD @ EPFL) | A popular approach for realizing a fault-tolerant quantum computer is to construct logical qubits encoded in multiple physical two-level qubits. Recent alternative approaches are based on bosonic quantum codes which are quantum error correcting (QEC) codes that redundantly encode quantum information in the states of a quantum harmonic oscillator, making it possible to detect and correct errors, while reducing the hardware resource overhead. In this talk, I will provide an overview of QEC in bosonic systems and review various bosonic quantum codes such as GKP and cat codes. Furthermore, I will show recent results on a novel bosonic quantum code, called the squeezed cat code, that enables to correct both dephasing and loss errors. We show that with moderate squeezing, and using typical parameters of state-of-the-art quantum hardware platforms, the squeezed cat code has a resilience to loss errors and dephasing errors that significantly outperform that of the conventional cat code. | Link |
| 29.03.2022 | Hardware-Tailored Diagonalization Circuits | Daniel Miller (PhD @ IBM) | A central building block of many quantum algorithms is the diagonalization of Pauli operators. Although it is always possible to construct a quantum circuit that simultaneously diagonalizes a given set of commuting Pauli operators, only resource-efficient circuits are reliably executable on near-term quantum computers. Generic diagonalization circuits can lead to an unaffordable Swap-gate overhead on quantum devices with limited hardware connectivity. A common alternative is excluding two-qubit gates, however, this comes at the cost of restricting the class of diagonalizable sets of Pauli operators to tensor product bases (TPBs). In this letter, we introduce a theoretical framework for constructing hardware-tailored (HT) diagonalization circuits. We apply our framework to group the Pauli operators occurring in the decomposition of a given Hamiltonian into jointly-HT-diagonalizable sets. We investigate several classes of popular Hamiltonians and observe that our approach requires a smaller number of measurements than conventional TPB approaches. Finally, we experimentally demonstrate the practical applicability of our technique, which showcases the great potential of our circuits for near-term quantum computing. | Link |
| 22.03.2022 | Photon-Pair generation from single LiNbO3 microcubes and GaAs nanowires | Saerens Grégoire (PhD @ ETH) | Nonclassical light sources are highly sought after as they are an integral part of quantum communication and quantum computation devices. Typical sources rely on bulk crystals that are not compact and have limited bandwidth due to phase-matching conditions. Here I will present generation of photon pairs at the telecommunication wavelength from free-standing LiNbO 3 microcubes and free-standing GaAs cut Nanowires using the spontaneous parametric down- conversion process. I will show the fabrication process for each of this nanostructure, the setup configuration for free space spontaneous parametric down-conversion, as well as the alignment challenges when trying to observe this wavelength conversion process in transmission. We will compare experimental as well as simulation results for both nanostructures. | Link |
| 15.03.2022 | No session – Pauli Lectures | |||
| 08.03.2022 | Quantum Memories in a Quantum Network | Moritz Businger (PhD @ UNIGE) | Quantum memories are one of the corner stones in a quantum network. It enables communication beyond the loss limit of direct communication and lets us use more complex protocols for quantum computation. Here I will present the ensemble based quantum memory approach we are perusing in Geneva and show how this lets us store a record number of quantum states in a rare earth ion doped crystal. Especially our recent work on Ytterbium is very competitive in terms of capacity and storage time which makes it a perfect candidate implementation in a largescale quantum network. | |
| 01.03.2022 | Blueprint for a Scalable Photonic Fault-Tolerant Quantum Computer | Ilan Tzitrin and Eli Bourassa (Xanadu) | Link | |
| 14.12.2021 | Realizing Repeated Quantum Error Correction in a Distance-Three Surface Code | Nathan Lacroix (PhD @ Qudev, ETH) | Link | |
| 07.11.2021 | Joint measurability of binary qubit measurements | Dmitry Grinko (PhD @ U. o. Amsterdam) | ||
| 30.11.2021 | An addressable quantum dot qubit with fault-tolerant control-fidelity | Markus Niese | Link | |
| 23.11.2021 | Universal quantum computation with ideal Clifford gates and noisy ancillas | Ivan Rojkov (PhD @ TIQI, ETH) | Link | |
| 16.11.2021 | Frequency-domain Hong-Ou-Mandel interference | Dario Scheiwiller | Link | |
| 09.11.2021 | Strong Optomechanical Coupling at Room Temperature | Dr. Nadine Meyer (Senior Scientist @ NSL, ETH) | — | |
| 02.11.2021 | Measurement of Subpicosecond Time Intervals between Two Photons by Interference | Moritz Fontboté Schmidt | Link | |
| 26.10.2021 | Test of the Local Realism and Realism in Particle Physics | Anna Efimova | Link | |
| 21.10.2021 | Stabilization and operation of a Kerr-cat qubit in a nonlinear superconducting resonator | Dr. Alexander Grimm (PSI) | Link | |
| 14.10.2021 | Error correction with real-time Feedback for Surface 17 on the Zurich Instruments setup | Liberto Beltrán | ||
07.10.2021 | Demonstrating the power of state-of-the-art quantum computers | Elisa Bäumer (PhD @ Renner/ETH+IBM) | ||
01.07.2021 | Bulk crystalline optomechanics | Elisa Bäumer (PhD @ Renner/ETH+IBM) | Link | |
24.06.2021 | Constructing quantum codes from any classical code and their embedding in ground space of local Hamiltonians | Dina Abdelhadi, (PhD @ EPFL) | Link | |
17.06.2021 | Controlling the competition between coherent and dissipative processes in a superradiant quantum gas. | Francesco Ferri (Postdoc @ Esslinger/ETH) | Link | |
10.06.21 | Strawberry Fields: A Software Platform for Photonic Quantum Computing | Ivan Rojkov/Moritz Fontboté Schmidt | Link | |
| 03.06.2021 | A gate-tunable, field-compatible fluxonium | Marta Pita Vidal (TU Delft) | Link | |
| 27.05.2021 | Qiskit Pulse: Programming Quantum Computers Through the Cloud with Pulses | Caroline Tornow | Link | |
| 20.05.2021 | Quantum Architecture Search via Deep Reinforcement Learning | Kristina Kirova | Link | |
| 13.05.2021 | Generation of Nonclassical Motional States of a Trapped Atom | Moritz Fontboté Schmidt | Link | |
| 06.05.2021 | Quantum acoustics with superconducting qubits | Alessandro Bruno | Link | |
| 29.04.2021 | Chiral Quantum Optics | Chaoxin Ding | Link | |
| 15.04.2021 | Quantum error correction of a qubit encoded in grid states of an oscillator | Alec Eickbusch (PhD student at Prof. Devoret’s Qulab at Yale University) | Link | |
| 01.04.2021 | A four-qubit germanium quantum processor | Ivan Rojkov | Link | |
| 25.03.2021 | Predicting many properties of a quantum system from very few measurements | Ivan Rojkov | Link | |
| 18.03.2021 | A network-ready random-access qubits memory | Stefano Marti | Link | |
| 11.03.2021 | How to put quantum particles on magic bullet trajectories that can hit two targets without a clear line-of-sight | Ivan Rojkov | Link | |
| 02.03.2021 | SpinQ Gemini: a desktop quantum computer for education and research | Moritz Fontboté Schmidt | Link | |
| 23.02.2021 | Strongly correlated Fermions strongly coupled to light | Prof. Jean-Philippe Brantut (EPFL) | Laboratory for Quantum Gases | |
| 08.12.2020 | Error correction of a logical grid state qubit by dissipative pumping | Ivan Rojkov & Moritz Fontboté Schmidt | Link | |
| 1.12.2020 | Observation of coherent optical information storage in anatomic medium using halted light pulses | Moritz Fontboté Schmidt | Link | |
| 24.11.2020 | Quantum memories for photons | Dr. Mikael Afzelius | Quantum Repeaters & Memories | |
| 17.11.2020 | Measurement of subpicosecond time intervals between two photons by interference | Moritz Fontboté Schmidt | Link | |
| 10.11.2020 | Quantum-dot spin–photon entanglement via frequency downconversion to telecom wavelength | Marco Stucki | Link | |
| 03.11.2020 | Observation of entanglement between a quantum dot spin and a single photon | Chaoxin Ding | Link | |
| 27.10.2020 | An introduction to Pound–Drever–Hall laser frequency stabilization | Moritz Fontbote Schmidt & Benjamin van Ommen | Link | |
| 20.10.2020 | Cavity Quantum Electrodynamics at Arbitrary Light-Matter Coupling Strengths | Alperen Tügen | Link | |
| 13.10.2020 | Architecture for a large-scale ion-trapquantum computer | Ivan Rojkov | Link | |
| 06.10.2020 | Interaction-assisted reversal of thermopower with ultracold atoms | Moritz Fontbote Schmidt | Link | |
| 29.09.2020 | Charge Insensitive Qubit Design derived from the Cooper Pair Box | Moritz Fontbote Schmidt | Link | |
| 22.09.2020 | Hartree-Fock on a superconducting qubit quantum computer | Ivan Rojkov | Link | |
| 21.07.2020 | Generation of entangled photon states in optical down-conversion and up-conversion processes. | Sahnawaz Alam (MSc in Physics at Indian Institute of Technology Gandhinagar) | ||
| 07.07.2020 | From nanotech to living sensors:unraveling the spin physics of biosensing at the nanoscale | Prof. Clarice D. Aiello (Assistant professor at UCLA and head of the Quantum Biology Tech (QuBiT) Lab ) | ||
| 30.06.2020 | Direct Measurement of the Density Matrix of a Quantum System | Alperen Tügen | Paper | |
| 23.06.2020 | Proof-of-concept proposal for machine learning using superconducting qubits (Master Thesis) | Colin Scarato | Contact speaker | |
| 16.06.2020 | Normal-Mode Splitting in a Weakly Coupled Optomechanical System | Francesco Adinolfi | Paper | |
| 09.06.2020 | Optimal cooling of a spin-boson system | Emanuel Malvetti (Semester thesis) | Contact speaker | |
| 02.06.2020 | Direct measurement of the Zak phase in topological Bloch bands | Benjamin van Ommen | Paper | |
| 26.05.2020 | Ramsey interferometry with dissipative quantum error correction | Ivan Rojkov (Semester thesis) | Contact speaker | |
| 19.05.2020 | Cavity-Based 3D Cooling of a Levitated Nanoparticle via Coherent Scattering | Dominik Windey (Phd Student in the Novotny/Photonics group) | Paper, PDF of presentation | |
| 12.05.2020 | Integrated optical multi-ion quantum logic | Chi Zhang (PhD student in the Home/TIQIgroup) | Paper | |
| 05.05.2020 | Topological Quantum Computing | Oriel Kiss | Lecture notes by Preskill | |
| 28.04.2020 | Remote quantum entanglement between two micromechanical oscillators | Marco Stucki | Paper | |
| 21.04.2020 | Non-classical correlations between single photons and phonons from a mechanical oscillator | Chaoxin Ding | Paper | |
| 15.04.2020 | Reinforcement Learning in Different Phases of Quantum Control | Pedro Rosso | Paper | |
| 08.04.2020 | Cavity-Assisted Quantum Bath Engineering | Moritz Fontboté Schmidt | Paper | |
| 1.04.2020 | Error-mitigated quantum gates exceeding physical fidelities in a trapped-ion system | Moritz Fontboté Schmidt | Paper | |
| (Corona-break) | ||||
| 10.03.2020 | To catch and reverse a quantum jump mid flight | Alperen Tugen | Paper | |
| 02.03.2020 | Entanglement of two quantum memories via fibres over dozens of kilometres | Moritz Fontboté Schmidt | Paper | |
| 25.02.2020 | Atom-by-atom assembly of defect-free one-dimensional cold atom arrays | Yongxin Song | Paper | |
| 18.02.2020 | Fast two-qubit logic with holes in Germanium | Moritz Fontboté Schmidt | Paper | |
| 17.12.19 | How often should you beat your kids? | Moritz Fontboté Schmidt | Paper | |
| 10.12.2019 | Single-Shot Quantum Nondemolition Detection of Individual Itinerant Microwave Photons | Moritz Fontboté Schmidt | Paper | |
| 03.12.2019 | Universal Gate for Fixed-Frequency Qubits via a Tunable Bus | Moritz Fontboté Schmidt | Paper | |
| 26.11.2019 | Ultracold and unreactive fermionic molucules and A degenerate Fermi gas of polar Molecules | Marit Fiechter | Paper and Paper | |
| 19.11.2019 | Measurement of subpicosecond time intervals between two photons by interference | Moritz Fontboté Schmidt | Paper | |
| 12.11.2019 | Towards fault-tolerant quantum computing with trapped ions | Moritz Fontboté Schmidt | Paper | |
| 05.11.2019 | Quantum Computations with Cold Trapped Ions | Moritz Fontboté Schmidt | Paper | |
| 29.10.2019 | Nanoscale imaging magnetometry with diamond spins under ambient conditions | Alperen Tügen, Moritz Fontboté Schmidt | Paper | |
| 22.10.2019 | Charge Insensitive qubit design derived from the cooper pair box | Benjamin Van Ommen, Alperen Tugen, Moritz Fontboté Schmidt | Paper |
If not noted otherwise, presenters were ETH students.