Project acronym 2D4QT
Project 2D Materials for Quantum Technology
Researcher (PI) Christoph STAMPFER
Host Institution (HI) RHEINISCH-WESTFAELISCHE TECHNISCHE HOCHSCHULE AACHEN
Call Details Consolidator Grant (CoG), PE3, ERC-2018-COG
Summary Since its discovery, graphene has been indicated as a promising platform for quantum technologies (QT). The number of theoretical proposal dedicated to this vision has grown steadily, exploring a wide range of directions, ranging from spin and valley qubits, to topologically-protected states. The experimental confirmation of these ideas lagged so far significantly behind, mostly because of material quality problems. The quality of graphene-based devices has however improved dramatically in the past five years, thanks to the advent of the so-called van der Waals (vdW) heteostructures - artificial solids formed by mechanically stacking layers of different two dimensional (2D) materials, such as graphene, hexagonal boron nitride and transition metal dichalcogenides. These new advances open now finally the door to put several of those theoretical proposals to test.
The goal of this project is to assess experimentally the potential of graphene-based heterostructures for QT applications. Specifically, I will push the development of an advanced technological platform for vdW heterostructures, which will allow to give quantitative answers to the following open questions: i) what are the relaxation and coherence times of spin and valley qubits in isotopically purified bilayer graphene (BLG); ii) what is the efficiency of a Cooper-pair splitter based on BLG; and iii) what are the characteristic energy scales of topologically protected quantum states engineered in graphene-based heterostructures.
At the end of this project, I aim at being in the position of saying whether graphene is the horse-worth-betting-on predicted by theory, or whether it still hides surprises in terms of fundamental physics. The technological advancements developed in this project for integrating nanostructured layers into vdW heterostructures will reach even beyond this goal, opening the door to new research directions and possible applications.
Summary
Since its discovery, graphene has been indicated as a promising platform for quantum technologies (QT). The number of theoretical proposal dedicated to this vision has grown steadily, exploring a wide range of directions, ranging from spin and valley qubits, to topologically-protected states. The experimental confirmation of these ideas lagged so far significantly behind, mostly because of material quality problems. The quality of graphene-based devices has however improved dramatically in the past five years, thanks to the advent of the so-called van der Waals (vdW) heteostructures - artificial solids formed by mechanically stacking layers of different two dimensional (2D) materials, such as graphene, hexagonal boron nitride and transition metal dichalcogenides. These new advances open now finally the door to put several of those theoretical proposals to test.
The goal of this project is to assess experimentally the potential of graphene-based heterostructures for QT applications. Specifically, I will push the development of an advanced technological platform for vdW heterostructures, which will allow to give quantitative answers to the following open questions: i) what are the relaxation and coherence times of spin and valley qubits in isotopically purified bilayer graphene (BLG); ii) what is the efficiency of a Cooper-pair splitter based on BLG; and iii) what are the characteristic energy scales of topologically protected quantum states engineered in graphene-based heterostructures.
At the end of this project, I aim at being in the position of saying whether graphene is the horse-worth-betting-on predicted by theory, or whether it still hides surprises in terms of fundamental physics. The technological advancements developed in this project for integrating nanostructured layers into vdW heterostructures will reach even beyond this goal, opening the door to new research directions and possible applications.
Max ERC Funding
1 806 250 €
Duration
Start date: 2019-09-01, End date: 2024-08-31
Project acronym ABSOLUTESPIN
Project Absolute Spin Dynamics in Quantum Materials
Researcher (PI) Christian Reinhard Ast
Host Institution (HI) MAX-PLANCK-GESELLSCHAFT ZUR FORDERUNG DER WISSENSCHAFTEN EV
Call Details Consolidator Grant (CoG), PE3, ERC-2015-CoG
Summary One of the greatest challenges in exploiting the electron spin for information processing is that it is not a conserved quantity like the electron charge. In addition, spin lifetimes are rather short and correspondingly coherence is quickly lost. This challenge culminates in the coherent manipulation and detection of information from a single spin. Except in a few special systems, so far, single spins cannot be manipulated coherently on the atomic scale, while spin coherence times can only be measured on spin ensembles. A new concept is needed for coherence measurements on arbitrary single spins. Here, the principal investigator (PI) will combine a novel time- and spin-resolved low-temperature scanning tunneling microscope (STM) with the concept of pulsed electron paramagnetic resonance. With this unique and innovative setup, he will be able to address long-standing problems, such as relaxation and coherence times of arbitrary single spin systems on the atomic scale as well as individual spin interactions with the immediate surroundings. Spin readout will be realized through the detection of the absolute spin polarization in the tunneling current by a superconducting tip based on the Meservey-Tedrow-Fulde effect, which the PI has recently demonstrated for the first time in STM. For the coherent excitation, a specially designed pulsed GHz light source will be implemented. The goal is to better understand the spin dynamics and coherence times of single spin systems as well as the spin interactions involved in the decay mechanisms. This will have direct impact on the feasibility of quantum spin information processing with single spin systems on different decoupling surfaces and their scalability at the atomic level. A successful demonstration will enhance the detection limit of spins by several orders of magnitude and fill important missing links in the understanding of spin dynamics and quantum computing with single spins.
Summary
One of the greatest challenges in exploiting the electron spin for information processing is that it is not a conserved quantity like the electron charge. In addition, spin lifetimes are rather short and correspondingly coherence is quickly lost. This challenge culminates in the coherent manipulation and detection of information from a single spin. Except in a few special systems, so far, single spins cannot be manipulated coherently on the atomic scale, while spin coherence times can only be measured on spin ensembles. A new concept is needed for coherence measurements on arbitrary single spins. Here, the principal investigator (PI) will combine a novel time- and spin-resolved low-temperature scanning tunneling microscope (STM) with the concept of pulsed electron paramagnetic resonance. With this unique and innovative setup, he will be able to address long-standing problems, such as relaxation and coherence times of arbitrary single spin systems on the atomic scale as well as individual spin interactions with the immediate surroundings. Spin readout will be realized through the detection of the absolute spin polarization in the tunneling current by a superconducting tip based on the Meservey-Tedrow-Fulde effect, which the PI has recently demonstrated for the first time in STM. For the coherent excitation, a specially designed pulsed GHz light source will be implemented. The goal is to better understand the spin dynamics and coherence times of single spin systems as well as the spin interactions involved in the decay mechanisms. This will have direct impact on the feasibility of quantum spin information processing with single spin systems on different decoupling surfaces and their scalability at the atomic level. A successful demonstration will enhance the detection limit of spins by several orders of magnitude and fill important missing links in the understanding of spin dynamics and quantum computing with single spins.
Max ERC Funding
2 469 136 €
Duration
Start date: 2016-07-01, End date: 2021-06-30
Project acronym CellStructure
Project Structural cell biology in situ using superresolution microscopy
Researcher (PI) Jonas RIES
Host Institution (HI) EUROPEAN MOLECULAR BIOLOGY LABORATORY
Call Details Consolidator Grant (CoG), PE3, ERC-2016-COG
Summary Supra-molecular protein machineries control diverse cellular processes. Knowing their structural organization is crucial for understanding their function. As classical structural biology techniques are limited in studying such assemblies in their natural cellular environment, there is a critical methodological gap inhibiting a direct link between structure and function. Consequently, the structural intermediates underlying a full activity cycle of a large multi-protein complex have been impossible to visualize. Recent advances in fluorescence microscopy, in particular the development of groundbreaking superresolution microscopy (SRM) methods, can now help bridge this gap. With this interdisciplinary proposal, my group will develop unique and innovative optical, biological and computational imaging technologies to determine the structural organization of multi-protein assemblies in their functional cellular context.
We will reach this goal by developing a method to robustly measure the precise 3D arrangements of proteins in supra-molecular assemblies in situ with nanometer isotropic resolution based on supercritical-angle detection and by measuring their absolute stoichiometries with engineered counting standards. We will also develop new data analysis tools to statistically analyze such data, taking into account the functional cellular context measured with correlative superresolution and electron microscopy, multi-color SRM and molecular biology tools. We will apply these new methods to address key questions on endocytosis, a fundamental membrane trafficking process. Our aim is to determine a time-resolved 3D superresolution localization map of the yeast endocytic proteins during the major functional transitions and to integrate these data into a mechanistic model of endocytosis. Importantly, the methods we develop here can be applied to many other large protein-based machines, and thus have the potential to have high impact in other key areas of cell biology.
Summary
Supra-molecular protein machineries control diverse cellular processes. Knowing their structural organization is crucial for understanding their function. As classical structural biology techniques are limited in studying such assemblies in their natural cellular environment, there is a critical methodological gap inhibiting a direct link between structure and function. Consequently, the structural intermediates underlying a full activity cycle of a large multi-protein complex have been impossible to visualize. Recent advances in fluorescence microscopy, in particular the development of groundbreaking superresolution microscopy (SRM) methods, can now help bridge this gap. With this interdisciplinary proposal, my group will develop unique and innovative optical, biological and computational imaging technologies to determine the structural organization of multi-protein assemblies in their functional cellular context.
We will reach this goal by developing a method to robustly measure the precise 3D arrangements of proteins in supra-molecular assemblies in situ with nanometer isotropic resolution based on supercritical-angle detection and by measuring their absolute stoichiometries with engineered counting standards. We will also develop new data analysis tools to statistically analyze such data, taking into account the functional cellular context measured with correlative superresolution and electron microscopy, multi-color SRM and molecular biology tools. We will apply these new methods to address key questions on endocytosis, a fundamental membrane trafficking process. Our aim is to determine a time-resolved 3D superresolution localization map of the yeast endocytic proteins during the major functional transitions and to integrate these data into a mechanistic model of endocytosis. Importantly, the methods we develop here can be applied to many other large protein-based machines, and thus have the potential to have high impact in other key areas of cell biology.
Max ERC Funding
1 686 469 €
Duration
Start date: 2017-06-01, End date: 2022-05-31
Project acronym DarkSERS
Project Harvesting dark plasmons for surface-enhanced Raman scattering
Researcher (PI) Stephanie REICH
Host Institution (HI) FREIE UNIVERSITAET BERLIN
Call Details Consolidator Grant (CoG), PE3, ERC-2017-COG
Summary Metal nanostructures show pronounced electromagnetic resonances that arise from localized surface plasmons. These collective oscillations of free electrons in the metal give rise to confined electromagnetic near fields. Surface-enhanced spectroscopy exploits the near-field intensity to enhance the optical response of nanomaterials by many orders of magnitude.
Plasmons are classified as bright and dark depending on their interaction with far-field radiation. Bright modes are dipole-allowed excitations that absorb and scatter light. Dark modes are resonances of the electromagnetic near field only that do not couple to propagating modes. The suppressed photon emission of dark plasmons makes their resonances spectrally narrow and intense, which is highly desirable for enhanced spectroscopy as well as storing and transporting electromagnetic energy in nanostructures. The suppressed absorption, however, prevents us from routinely exploiting dark modes in nanoplasmonic systems.
I propose using spatially patterned light beams to excite dark plasmons with far-field radiation. By this I mean a beam profile with varying polarization and intensity that will be matched to the dark electromagnetic eigenmode. My approach activates the excitation of dark modes, while their radiative decay remains suppressed. I will show how to harvest dark modes for surface-enhanced Raman scattering providing superior intensity and an enhancement that is tailored to a specific vibration. Another feature of dark modes is their strong coupling to the vibrations of nanostructures. I will use this to amplify vibrational modes and, ultimately, induce phonon lasing.
The proposed research aims at an enabling technology that unlocks a novel range of nanoplasmonic properties. It will put dark plasmons on par with the well-recognized bright modes to be used in fundamental science and for applications in analytics, optoelectronic, and nanoimaging.
Summary
Metal nanostructures show pronounced electromagnetic resonances that arise from localized surface plasmons. These collective oscillations of free electrons in the metal give rise to confined electromagnetic near fields. Surface-enhanced spectroscopy exploits the near-field intensity to enhance the optical response of nanomaterials by many orders of magnitude.
Plasmons are classified as bright and dark depending on their interaction with far-field radiation. Bright modes are dipole-allowed excitations that absorb and scatter light. Dark modes are resonances of the electromagnetic near field only that do not couple to propagating modes. The suppressed photon emission of dark plasmons makes their resonances spectrally narrow and intense, which is highly desirable for enhanced spectroscopy as well as storing and transporting electromagnetic energy in nanostructures. The suppressed absorption, however, prevents us from routinely exploiting dark modes in nanoplasmonic systems.
I propose using spatially patterned light beams to excite dark plasmons with far-field radiation. By this I mean a beam profile with varying polarization and intensity that will be matched to the dark electromagnetic eigenmode. My approach activates the excitation of dark modes, while their radiative decay remains suppressed. I will show how to harvest dark modes for surface-enhanced Raman scattering providing superior intensity and an enhancement that is tailored to a specific vibration. Another feature of dark modes is their strong coupling to the vibrations of nanostructures. I will use this to amplify vibrational modes and, ultimately, induce phonon lasing.
The proposed research aims at an enabling technology that unlocks a novel range of nanoplasmonic properties. It will put dark plasmons on par with the well-recognized bright modes to be used in fundamental science and for applications in analytics, optoelectronic, and nanoimaging.
Max ERC Funding
2 299 506 €
Duration
Start date: 2018-04-01, End date: 2023-03-31
Project acronym DNA ORIGAMI MOTORS
Project Constructing and powering nanoscale DNA origami motors
Researcher (PI) Hendrik DIETZ
Host Institution (HI) TECHNISCHE UNIVERSITAET MUENCHEN
Call Details Consolidator Grant (CoG), PE3, ERC-2016-COG
Summary Our goal is to advance the field of DNA nanotechnology by achieving directed transport on the nanoscale using robustly functioning synthetic motor units. To do so, we propose to construct spatially periodic, diffusive mechanisms that have broken inversion symmetry and to subject these mechanisms to conditions away from thermal equilibrium. We will build on recent progress in creating complex DNA-based structures and construct various nanoscale rotary and translational Brownian ratchet mechanisms that have well- defined degrees of freedom for motion within periodic and asymmetric energy landscapes. The mechanisms will be self-assembled from DNA origami components. We will use cryo-Transmission Electron Microscopy (TEM) to evaluate and iteratively refine our structures. Conventional video-rate fluorescence microscopy, in addition to super-resolution microscopy, will be employed to study in solution and in real time the diffusive motion of the mechanisms on the single particle level. We will introduce various deterministic or stochastic thermal, mechanical, or chemical perturbations to drive the systems away from thermal equilibrium. We will use laser heating and cooling to experimentally test thermal and flashing ratcheting mechanisms; we will employ dissipative asymmetric fluxes arising in active matter as realized in high-density ATP-hydrolysing motility assays; and we will couple out-of-equilibrium chemical reactions to the motion of our mechanisms. The ultimate goal of our work is to take insights from these experiments and create robustly functioning nanoscale motor units that can drive directed motion against external load and perform at levels comparable to those of natural macromolecular motor proteins. Achieving this goal will create unprecedented technological opportunities, for example, to drive chemical synthesis, actively propel nanoscale drug- delivery vehicles, pump and separate molecules across barriers or package molecules into cargo components.
Summary
Our goal is to advance the field of DNA nanotechnology by achieving directed transport on the nanoscale using robustly functioning synthetic motor units. To do so, we propose to construct spatially periodic, diffusive mechanisms that have broken inversion symmetry and to subject these mechanisms to conditions away from thermal equilibrium. We will build on recent progress in creating complex DNA-based structures and construct various nanoscale rotary and translational Brownian ratchet mechanisms that have well- defined degrees of freedom for motion within periodic and asymmetric energy landscapes. The mechanisms will be self-assembled from DNA origami components. We will use cryo-Transmission Electron Microscopy (TEM) to evaluate and iteratively refine our structures. Conventional video-rate fluorescence microscopy, in addition to super-resolution microscopy, will be employed to study in solution and in real time the diffusive motion of the mechanisms on the single particle level. We will introduce various deterministic or stochastic thermal, mechanical, or chemical perturbations to drive the systems away from thermal equilibrium. We will use laser heating and cooling to experimentally test thermal and flashing ratcheting mechanisms; we will employ dissipative asymmetric fluxes arising in active matter as realized in high-density ATP-hydrolysing motility assays; and we will couple out-of-equilibrium chemical reactions to the motion of our mechanisms. The ultimate goal of our work is to take insights from these experiments and create robustly functioning nanoscale motor units that can drive directed motion against external load and perform at levels comparable to those of natural macromolecular motor proteins. Achieving this goal will create unprecedented technological opportunities, for example, to drive chemical synthesis, actively propel nanoscale drug- delivery vehicles, pump and separate molecules across barriers or package molecules into cargo components.
Max ERC Funding
2 000 000 €
Duration
Start date: 2017-05-01, End date: 2022-04-30
Project acronym DYNACQM
Project Dynamics of Correlated Quantum Matter: From Dynamical Probes to Novel Phases of Matter
Researcher (PI) Frank POLLMANN
Host Institution (HI) TECHNISCHE UNIVERSITAET MUENCHEN
Call Details Consolidator Grant (CoG), PE3, ERC-2017-COG
Summary The interplay of quantum fluctuations and correlation effects in condensed matter can yield emergent phases with fascinating properties. Understanding these challenging quantum-many body systems is a problem of central importance in theoretical physics and the basis for the development of new materials for future technologies. Dynamical properties can provide characteristic fingerprints that allow to identify novel phases in newly synthesized materials and optical lattice systems. Moreover, when brought out of equilibrium, correlated quantum matter can exhibit dynamical phases that cannot occur in equilibrium settings.
DYNACQM will develop new theoretical and numerical frameworks to study dynamical properties of correlated quantum matter. On the theoretical side, we will investigate how many-body entanglement affects dynamical properties and predict universal features that can be measured in experiments. For example, dynamical spin correlation functions, measured in neutron scattering experiments, provide signatures of topologically ordered spin liquids. Furthermore, we will study the role of disorder and many-body localization in static as well as in driven quantum systems. On the numerical side, we will develop efficient tensor-product state based algorithms to simulate the dynamics of quantum many-body systems. These will allow us to study realistic microscopic model systems and to understand their dynamical properties.
Recent developments in the creation of synthetic quantum systems and advances in high resolution spectroscopy allow for an unprecedented precision with which the dynamics of quantum systems can be studied and manipulated experimentally. In this light, it is particularly important to theoretically understand the dynamics of correlated quantum systems and to make testable predictions. DYNACQM will bridge between the fundamental understanding of many-body entanglement in correlated quantum matter and experiments.
Summary
The interplay of quantum fluctuations and correlation effects in condensed matter can yield emergent phases with fascinating properties. Understanding these challenging quantum-many body systems is a problem of central importance in theoretical physics and the basis for the development of new materials for future technologies. Dynamical properties can provide characteristic fingerprints that allow to identify novel phases in newly synthesized materials and optical lattice systems. Moreover, when brought out of equilibrium, correlated quantum matter can exhibit dynamical phases that cannot occur in equilibrium settings.
DYNACQM will develop new theoretical and numerical frameworks to study dynamical properties of correlated quantum matter. On the theoretical side, we will investigate how many-body entanglement affects dynamical properties and predict universal features that can be measured in experiments. For example, dynamical spin correlation functions, measured in neutron scattering experiments, provide signatures of topologically ordered spin liquids. Furthermore, we will study the role of disorder and many-body localization in static as well as in driven quantum systems. On the numerical side, we will develop efficient tensor-product state based algorithms to simulate the dynamics of quantum many-body systems. These will allow us to study realistic microscopic model systems and to understand their dynamical properties.
Recent developments in the creation of synthetic quantum systems and advances in high resolution spectroscopy allow for an unprecedented precision with which the dynamics of quantum systems can be studied and manipulated experimentally. In this light, it is particularly important to theoretically understand the dynamics of correlated quantum systems and to make testable predictions. DYNACQM will bridge between the fundamental understanding of many-body entanglement in correlated quantum matter and experiments.
Max ERC Funding
1 998 750 €
Duration
Start date: 2018-06-01, End date: 2023-05-31
Project acronym Dynasore
Project Dynamical magnetic excitations with spin-orbit interaction in realistic nanostructures
Researcher (PI) Samir Lounis
Host Institution (HI) FORSCHUNGSZENTRUM JULICH GMBH
Call Details Consolidator Grant (CoG), PE3, ERC-2015-CoG
Summary Nano-spin-orbitronics is an emerging and fast growing field that aims at combining three degrees of freedom − spin, charge and spin-orbit interaction − to explore new nanotechnologies stemming from fundamental physics. New magnetic phases of matter are investigated using, in particular, atomic design to tailor beneficial physical properties down to the atomic level. Storage, transport and manipulation of magnetic information within a small set of atoms does not only require a fundamental understanding of their ground-state properties from the perspective of quantum mechanics, but crucially also their dynamical excited states. We propose to go beyond the state of the art by investigating from first-principles the dynamical properties of chiral spin textures in nanostructures from 2-dimensions to 0-dimension with these nanostructures being deposited on different substrates where spin-orbit interaction plays a major role. Understanding their response to external dynamical fields (electric/magnetic) or currents will impact on the burgeoning field of nano-spin-orbitronics. Indeed, to achieve efficient manipulation of nano-sized functional spin textures, it is imperative to exploit and understand their resonant motion, analogous to the role of ferromagnetic resonance in spintronics. A magnetic skyrmion is an example of a spin-swirling texture characterized by a topological number that will be explored. This spin state has huge potential in nanotechnologies thanks to the low spin currents needed to manipulate it. Based on time-dependent density functional theory and many-body perturbation theory, our innovative scheme will deliver a paradigm shift with respect to existing theoretical methodologies and will provide a fundamental understanding of: (i) the occurrence of chiral spin textures in reduced dimensions, (ii) their dynamical spin-excitation spectra and the coupling of the different excitation degrees of freedom and (iii) their impact on the electronic structure.
Summary
Nano-spin-orbitronics is an emerging and fast growing field that aims at combining three degrees of freedom − spin, charge and spin-orbit interaction − to explore new nanotechnologies stemming from fundamental physics. New magnetic phases of matter are investigated using, in particular, atomic design to tailor beneficial physical properties down to the atomic level. Storage, transport and manipulation of magnetic information within a small set of atoms does not only require a fundamental understanding of their ground-state properties from the perspective of quantum mechanics, but crucially also their dynamical excited states. We propose to go beyond the state of the art by investigating from first-principles the dynamical properties of chiral spin textures in nanostructures from 2-dimensions to 0-dimension with these nanostructures being deposited on different substrates where spin-orbit interaction plays a major role. Understanding their response to external dynamical fields (electric/magnetic) or currents will impact on the burgeoning field of nano-spin-orbitronics. Indeed, to achieve efficient manipulation of nano-sized functional spin textures, it is imperative to exploit and understand their resonant motion, analogous to the role of ferromagnetic resonance in spintronics. A magnetic skyrmion is an example of a spin-swirling texture characterized by a topological number that will be explored. This spin state has huge potential in nanotechnologies thanks to the low spin currents needed to manipulate it. Based on time-dependent density functional theory and many-body perturbation theory, our innovative scheme will deliver a paradigm shift with respect to existing theoretical methodologies and will provide a fundamental understanding of: (i) the occurrence of chiral spin textures in reduced dimensions, (ii) their dynamical spin-excitation spectra and the coupling of the different excitation degrees of freedom and (iii) their impact on the electronic structure.
Max ERC Funding
1 994 879 €
Duration
Start date: 2016-06-01, End date: 2021-05-31
Project acronym EXQUISITE
Project External Quantum Control of Photonic Semiconductor Nanostructures
Researcher (PI) Stephan Erich Reitzenstein
Host Institution (HI) TECHNISCHE UNIVERSITAT BERLIN
Call Details Consolidator Grant (CoG), PE3, ERC-2013-CoG
Summary In this project, we will control photonic nanostructures by external feedback, optical injection and synchronization. This will allow us to study nonlinear dynamics in quantum systems and to externally manipulate and stabilize light-matter interaction in the regime of quantum electrodynamics (cQED). We will experimentally and theoretically address a) optical injection and feedback control of quantum dot (QD)–microlasers, b) quantum control cQED systems via delayed single photon feedback, and c) mutually coupled and synchronized chaotic microcavity systems. In a) we will advance the concepts of time-delayed coupling in standard semiconductor laser diodes to few photon states, where quantum fluctuations contribute to or even dominate over the usual classical dynamics. Feedback-coupling in microlasers will allow us to explore the limits of a classical description of chaotic laser dynamics via the Lang-Kobayashi rate equations and to develop an advanced model taking cQED- and QD-specific effects into account. This subject will be complemented by the study of optical injection of coherent light and non-classical light into microlasers to influence and study mode-locking, chaos and stimulated emission down to the quantum level. Single photon feedback in b) will be applied to stabilize coherent coupling of light and matter and to act against decoherence which constitutes a major bottleneck for application of semiconductor nanostructures in quantum information technology. In c) the mutual coupling of microlasers will be used to study synchronization of chaotic quantum devices at the single photon limit and to explore the underlying physics of isochronal synchronization. Our work will have important impact at an interdisciplinary level on the development of nonlinear dynamical systems towards the quantum limit and the understanding of fundamental light-matter interaction in the presence of time delayed single photon feedback.
Summary
In this project, we will control photonic nanostructures by external feedback, optical injection and synchronization. This will allow us to study nonlinear dynamics in quantum systems and to externally manipulate and stabilize light-matter interaction in the regime of quantum electrodynamics (cQED). We will experimentally and theoretically address a) optical injection and feedback control of quantum dot (QD)–microlasers, b) quantum control cQED systems via delayed single photon feedback, and c) mutually coupled and synchronized chaotic microcavity systems. In a) we will advance the concepts of time-delayed coupling in standard semiconductor laser diodes to few photon states, where quantum fluctuations contribute to or even dominate over the usual classical dynamics. Feedback-coupling in microlasers will allow us to explore the limits of a classical description of chaotic laser dynamics via the Lang-Kobayashi rate equations and to develop an advanced model taking cQED- and QD-specific effects into account. This subject will be complemented by the study of optical injection of coherent light and non-classical light into microlasers to influence and study mode-locking, chaos and stimulated emission down to the quantum level. Single photon feedback in b) will be applied to stabilize coherent coupling of light and matter and to act against decoherence which constitutes a major bottleneck for application of semiconductor nanostructures in quantum information technology. In c) the mutual coupling of microlasers will be used to study synchronization of chaotic quantum devices at the single photon limit and to explore the underlying physics of isochronal synchronization. Our work will have important impact at an interdisciplinary level on the development of nonlinear dynamical systems towards the quantum limit and the understanding of fundamental light-matter interaction in the presence of time delayed single photon feedback.
Max ERC Funding
1 999 800 €
Duration
Start date: 2014-04-01, End date: 2019-03-31
Project acronym FLATLAND
Project Electron-lattice-spin correlations and many-body phenomena in 2D semiconductors and related heterostructures
Researcher (PI) Ralph Bernhard Ernstorfer
Host Institution (HI) MAX-PLANCK-GESELLSCHAFT ZUR FORDERUNG DER WISSENSCHAFTEN EV
Call Details Consolidator Grant (CoG), PE3, ERC-2015-CoG
Summary Two-dimensional crystalline materials exhibit exceptional physical properties and offer fascinating potential as fundamental building blocks for future two-dimensional electronic and optoelectronic devices. Transition metal dichalcogenides (TMDCs) are of particular interest as they show a variety of many-body phenomena and correlation effects. Key properties are: i) additional internal degrees of freedom of the electrons, described as valley pseudospin and layer pseudospin, ii) electronic many-body effects like strongly-bound excitons and trions, and iii) electron-lattice correlations like polarons. While these phenomena represent intriguing fundamental solid state physics problems, they are of great practical importance in view of the envisioned nanoscopic devices based on two-dimensional materials.
The experimental research project FLATLAND will address the exotic spin-valley-layer correlations in few-layer thick TMDC crystals and TMDC-based heterostructures. The latter comprise other 2D materials, organic crystals, metals and phase change materials as second constituent. Microscopic coupling and correlation effects, both within pure materials as well as across the interface of heterostructures, will be accessed by time- and angle-resolved extreme ultraviolet-photoelectron spectroscopy, femtosecond electron diffraction, and time-resolved optical spectroscopies. The project promises unprecedented insight into the microscopic coupling mechanisms governing the performance of van der Waals-bonded devices.
Summary
Two-dimensional crystalline materials exhibit exceptional physical properties and offer fascinating potential as fundamental building blocks for future two-dimensional electronic and optoelectronic devices. Transition metal dichalcogenides (TMDCs) are of particular interest as they show a variety of many-body phenomena and correlation effects. Key properties are: i) additional internal degrees of freedom of the electrons, described as valley pseudospin and layer pseudospin, ii) electronic many-body effects like strongly-bound excitons and trions, and iii) electron-lattice correlations like polarons. While these phenomena represent intriguing fundamental solid state physics problems, they are of great practical importance in view of the envisioned nanoscopic devices based on two-dimensional materials.
The experimental research project FLATLAND will address the exotic spin-valley-layer correlations in few-layer thick TMDC crystals and TMDC-based heterostructures. The latter comprise other 2D materials, organic crystals, metals and phase change materials as second constituent. Microscopic coupling and correlation effects, both within pure materials as well as across the interface of heterostructures, will be accessed by time- and angle-resolved extreme ultraviolet-photoelectron spectroscopy, femtosecond electron diffraction, and time-resolved optical spectroscopies. The project promises unprecedented insight into the microscopic coupling mechanisms governing the performance of van der Waals-bonded devices.
Max ERC Funding
2 640 633 €
Duration
Start date: 2016-10-01, End date: 2021-09-30
Project acronym LASSO
Project Layered semiconductors and hybrid systems for quantum optics and opto-valleytronics
Researcher (PI) Alexander HOEGELE
Host Institution (HI) LUDWIG-MAXIMILIANS-UNIVERSITAET MUENCHEN
Call Details Consolidator Grant (CoG), PE3, ERC-2017-COG
Summary A new resource for quantum information processing has emerged recently in the form of the valley pseudospin in layered transition metal dichalcogenides. By virtue of strong spin-orbit and Berry curvature effects, these non-centrosymmetric crystals provide a quantum optical interface between spin- and valley-polarized electrons and circularly polarized photons. Such valley-contrasting optical selection rules in turn establish means to address the multivalley quantum resource all-optically. At this interface, where light meets valley quantum states of matter, the proposed research will aim at tailoring and mastering electron-hole-pair excitations and their coupling to photons in layered transition metal dichalcogenide semiconductors, heterostructures and hybrid systems. The project will combine semiconductor monolayers with ferroelectric and ferromagnetic supports to achieve synthetic opto-valleytronic functionality of substrate-modified excitons for the development of novel linear, non-linear and chiral quantum optical elements. Reciprocally, interfacial effect of the substrate on the valley dynamics of monolayer excitons will be utilized for the development of quantum-enhanced imaging of ferroic domain textures to facilitate fundamental studies of phase transitions in condensed matter systems. In parallel, we will develop on chip-circuitry to control long-lived dipolar excitons in hetero-bilayer semiconductors. Finally, light-matter quasiparticles in the form of exciton-polaritons with weak and strong mutual interactions in monolayer- and heterobilayer-cavity systems will be created, engineered and condensed at ultra-low temperatures into a macroscopic ground state. The realization of interacting polariton gases and condensates, paired with the opto-valleytronic phenomena inherent to layered transition metal dichalcogenides, will contribute topologically protected polaritons to the realm of systems with an integral role in all-optical quantum science and technology.
Summary
A new resource for quantum information processing has emerged recently in the form of the valley pseudospin in layered transition metal dichalcogenides. By virtue of strong spin-orbit and Berry curvature effects, these non-centrosymmetric crystals provide a quantum optical interface between spin- and valley-polarized electrons and circularly polarized photons. Such valley-contrasting optical selection rules in turn establish means to address the multivalley quantum resource all-optically. At this interface, where light meets valley quantum states of matter, the proposed research will aim at tailoring and mastering electron-hole-pair excitations and their coupling to photons in layered transition metal dichalcogenide semiconductors, heterostructures and hybrid systems. The project will combine semiconductor monolayers with ferroelectric and ferromagnetic supports to achieve synthetic opto-valleytronic functionality of substrate-modified excitons for the development of novel linear, non-linear and chiral quantum optical elements. Reciprocally, interfacial effect of the substrate on the valley dynamics of monolayer excitons will be utilized for the development of quantum-enhanced imaging of ferroic domain textures to facilitate fundamental studies of phase transitions in condensed matter systems. In parallel, we will develop on chip-circuitry to control long-lived dipolar excitons in hetero-bilayer semiconductors. Finally, light-matter quasiparticles in the form of exciton-polaritons with weak and strong mutual interactions in monolayer- and heterobilayer-cavity systems will be created, engineered and condensed at ultra-low temperatures into a macroscopic ground state. The realization of interacting polariton gases and condensates, paired with the opto-valleytronic phenomena inherent to layered transition metal dichalcogenides, will contribute topologically protected polaritons to the realm of systems with an integral role in all-optical quantum science and technology.
Max ERC Funding
1 996 291 €
Duration
Start date: 2019-01-01, End date: 2023-12-31
