Publications associées à Two-state quantum system

Emergence of highly coherent two-level systems in a noisy and dense quantum network

Quantum sensors and qubits are usually two-level systems (TLS), the quantum analogues of classical bits assuming binary values 0 or 1. They are useful to the extent to which superpositions of 0 and 1 persist despite a noisy environment. The standard prescr ...

Nature Portfolio2024

Adaptive variational low-rank dynamics for open quantum systems

Vincenzo Savona, Luca Gravina

We introduce a model-independent method for the efficient simulation of low-entropy systems, whose dynamics can be accurately described with a limited number of states. Our method leverages the time-dependent variational principle to efficiently integrate ...

Amer Physical Soc2024

Scalable Quantum Algorithms for Noisy Quantum Computers

Julien Sebastian Gacon

Quantum computing not only holds the potential to solve long-standing problems in quantum physics, but also to offer speed-ups across a broad spectrum of other fields. Access to a computational space that incorporates quantum effects, such as superposition ...

EPFL2024

A Cavity-Microscope for Quantum Simulations with Locally-Controllable All-to-All Interactions

Nick Jacob Sauerwein

This thesis presents the development, construction, and benchmark of an experimental platform that combines cold fermionic 6Li atoms with locally controllable light-matter interactions. To enable local control, a new device, the cavity-microscope, was crea ...

EPFL2024

Electron-beam based nanoscale quantum controls

Hoda Shirzad

Advancing quantum technologies depends on the precise control of individual quantum systems, the so-called qubits, and the exploitation of their quantum properties. Nowadays, expanding the number of qubits to be entangled is at the core of the developments ...

EPFL2024

Emergence of Classical Magnetic Order from Anderson Towers: Quantum Darwinism in Action

Frédéric Mila

Environment is assumed to play a negative role in quantum mechanics, destroying the coherence in a quantum system and, thus, randomly changing its state. However, for a quantum system that is initially in a degenerate ground state, the situation could be d ...

American Physical Society2023

Programmable frequency-bin quantum states in a nano-engineered silicon device

Matteo Galli, Marco Clementi

Frequency-bin qubits get the best of time-bin and dual-rail encodings, but require external modulators and pulse shapers to build arbitrary states. Here, instead, the authors work directly on-chip by controlling the interference of biphoton amplitudes gene ...

Nature Portfolio2023

NbN films with high kinetic inductance for high-quality compact superconducting resonators

Edoardo Charbon, Pasquale Scarlino, Fabrizio Minganti, Simone Frasca, Marco Scigliuzzo, Vincent Jean Yves Jouanny, Fabian Oppliger, Roberto Musio

Niobium nitride (NbN) is a particularly promising material for quantum technology applications, as it shows the degree of reproducibility necessary for large-scale superconducting circuits. We demonstrate that resonators based on NbN thin films present a o ...

American Physical Society (APS)2023

Optimizing Quantum Compilers: Efficient and Effective Algorithms

Fereshte Mozafari Ghoraba

Quantum computing has made significant progress in recent years, with Google and IBM releasing quantum computers with 72 and 50 qubits, respectively. Google has also achieved quantum supremacy with its 54-qubit device, and IBM has announced the release of ...

EPFL2023

Nonlocally-resonant metamaterials

Aleksi Antoine Bossart

In this thesis, we unveil a third design path to manipulate elastic waves within architected media, distinct from the traditional phononic crystal and locally-resonant metamaterial concepts. The core innovation lies in the concept of nonlocal resonances, d ...

EPFL2023

Creating and controlling exceptional points of non-Hermitian Hamiltonians via homodyne Lindbladian invariance

Fabrizio Minganti

The exceptional points (EPs) of non-Hermitian Hamiltonians (NHHs) are spectral degeneracies associated with coalescing eigenvalues and eigenvectors, which are associated with remarkable dynamical properties. These EPs can be generated experimentally in ope ...

AMER PHYSICAL SOC2022

Einstein's quantum elevator: Hermitization of non-Hermitian Hamiltonians via a generalized vielbein formalism

Fabrizio Minganti

The formalism for non-Hermitian quantum systems sometimes blurs the underlying physics. We present a systematic study of the vielbeinlike formalism which transforms the Hilbert space bundles of non-Hermitian systems into the conventional ones, rendering th ...

AMER PHYSICAL SOC2022

Observation of SQUID-Like Behavior in Fiber Laser with Intra-Cavity Epsilon-Near-Zero Effect

Camille Sophie Brès, Jiaye Wu, Marco Clementi, Qian Li, Xuanyi Liu

Establishing relations between fundamental effects in far-flung areas of physics is a subject of great interest in the current research. Realization of a novel photonic system akin to the radio-frequency superconducting quantum interference device (RF-SQUI ...

WILEY-V C H VERLAG GMBH2022

TimeEvolver: A program for time evolution with improved error bound

Sebastian Zell

We present TimeEvolver, a program for computing time evolution in a generic quantum system. It relies on well-known Krylov subspace techniques to tackle the problem of multiplying the exponential of a large sparse matrix iH, where His the Hamiltonian, with ...

ELSEVIER2022

Tunneling processes through magnetic impurities on superconducting surfaces: Yu-Shiba-Rusinov states and the Josephson effect

Haonan Huang

Magnetic impurities generate a wealth of phenomena on surfaces. On metals, conducting electrons screen the magnetic moment giving rise to the Kondo effect. On superconductors, the Yu-Shiba-Rusinov (YSR) states emerge inside the superconducting gap due to t ...

EPFL2021

Dynamical Localization Simulated on Actual Quantum Hardware

Su Yeon Chang

Quantum computers are invaluable tools to explore the properties of complex quantum systems. We show that dynamical localization of the quantum sawtooth map, a highly sensitive quantum coherent phenomenon, can be simulated on actual, small-scale quantum pr ...

MDPI2021

Local excitations in amorphous solids

Wencheng Ji

Amorphous solids are structurally disordered. They are very common and include glasses, colloids, and granular materials, but are far less understood than crystalline solids. Key aspects of these materials are controlled by the presence of excitations in w ...

EPFL2021

Non-Hermitian time evolution: From static to parametric instability

Romain Christophe Rémy Fleury, Aleksi Antoine Bossart

Eigenmode coalescence imparts remarkable properties to non-Hermitian time evolution, culminating in a purely non-Hermitian spectral degeneracy known as an exceptional point (EP). Here, we revisit time evolution around EPs, looking at both static and period ...

2021

Cryogenic CMOS Circuits and Systems: Challenges and Opportunities in Designing the Electronic Interface for Quantum Processors

Edoardo Charbon, Fabio Sebastiano

Quantum computing could potentially offer faster solutions for some of today's classically intractable problems using quantum processors as computational support for quantum algorithms [1]. Quantum processors, in the most frequent embodiment, comprise an a ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2021

Quantum interference effects of out-of-plane confinement on two-dimensional electron systems in oxides

Emmanouil Frantzeskakis, Ji Dai

It was recently discovered that a conductive, metallic state is formed on the surface of some insulating oxides. First observed on SrTiO3 (001), it was then found in other compounds as diverse as anatase TiO2, KTaO3, BaTiO3, ZnO, and also on different surf ...

2020