Project acronym AMPLITUDES
Project Manifesting the Simplicity of Scattering Amplitudes
Researcher (PI) Jacob BOURJAILY
Host Institution (HI) KOBENHAVNS UNIVERSITET
Call Details Starting Grant (StG), PE2, ERC-2017-STG
Summary I propose a program of research that may forever change the way that we understand and use quantum field theory to make predictions for experiment. This will be achieved through the advancement of new, constructive frameworks to determine and represent scattering amplitudes in perturbation theory in terms that depend only on observable quantities, make manifest (all) the symmetries of the theory, and which can be efficiently evaluated while minimally spoiling the underlying simplicity of predictions. My research has already led to the discovery and development of several approaches of this kind.
This proposal describes the specific steps required to extend these ideas to more general theories and to higher orders of perturbation theory. Specifically, the plan of research I propose consists of three concrete goals: to fully characterize the discontinuities of loop amplitudes (`on-shell functions') for a broad class of theories; to develop powerful new representations of loop amplitude {\it integrands}, making manifest as much simplicity as possible; and to develop new techniques for loop amplitude {integration} that are compatible with and preserve the symmetries of observable quantities.
Progress toward any one of these objectives would have important theoretical implications and valuable practical applications. In combination, this proposal has the potential to significantly advance the state of the art for both our theoretical understanding and our computational reach for making predictions for experiment.
To achieve these goals, I will pursue a data-driven, `phenomenological' approach—involving the construction of new computational tools, developed in pursuit of concrete computational targets. For this work, my suitability and expertise is amply demonstrated by my research. I have not only played a key role in many of the most important theoretical developments in the past decade, but I have personally built the most powerful computational tools for their
Summary
I propose a program of research that may forever change the way that we understand and use quantum field theory to make predictions for experiment. This will be achieved through the advancement of new, constructive frameworks to determine and represent scattering amplitudes in perturbation theory in terms that depend only on observable quantities, make manifest (all) the symmetries of the theory, and which can be efficiently evaluated while minimally spoiling the underlying simplicity of predictions. My research has already led to the discovery and development of several approaches of this kind.
This proposal describes the specific steps required to extend these ideas to more general theories and to higher orders of perturbation theory. Specifically, the plan of research I propose consists of three concrete goals: to fully characterize the discontinuities of loop amplitudes (`on-shell functions') for a broad class of theories; to develop powerful new representations of loop amplitude {\it integrands}, making manifest as much simplicity as possible; and to develop new techniques for loop amplitude {integration} that are compatible with and preserve the symmetries of observable quantities.
Progress toward any one of these objectives would have important theoretical implications and valuable practical applications. In combination, this proposal has the potential to significantly advance the state of the art for both our theoretical understanding and our computational reach for making predictions for experiment.
To achieve these goals, I will pursue a data-driven, `phenomenological' approach—involving the construction of new computational tools, developed in pursuit of concrete computational targets. For this work, my suitability and expertise is amply demonstrated by my research. I have not only played a key role in many of the most important theoretical developments in the past decade, but I have personally built the most powerful computational tools for their
Max ERC Funding
1 499 695 €
Duration
Start date: 2018-02-01, End date: 2023-01-31
Project acronym PUNCTUATION
Project Pervasive Upstream Non-Coding Transcription Underpinning Adaptation
Researcher (PI) Andreas Sebastian Marquardt
Host Institution (HI) KOBENHAVNS UNIVERSITET
Call Details Starting Grant (StG), LS2, ERC-2017-STG
Summary Genomic DNA represents the blueprint of life: it instructs solutions to challenges during life cycles of organisms. Curiously DNA in higher organisms is mostly non-protein coding (e.g. 97% in human). The popular “junk-DNA” hypothesis postulates that this non-coding DNA is non-functional. However, high-throughput transcriptomics indicates that this may be an over-simplification as most non-coding DNA is transcribed. This pervasive transcription yields two molecular events that may be functional: 1.) resulting long non-coding RNA (lncRNA) molecules, and 2.) the act of pervasive transcription itself. Whereas lncRNA sequences and functions differ on a case-by-case basis, RNA polymerase II (Pol II) transcribes most lncRNA. Pol II activity leaves molecular marks that specify transcription stages. The profiles of stage-specific activities instruct separation and fidelity of transcription units (genomic punctuation). Pervasive transcription affects genomic punctuation: upstream lncRNA transcription over gene promoters can repress downstream gene expression, also referred to as tandem Transcriptional Interference (tTI). Even though tTI was first reported decades ago a systematic characterization of tTI is lacking. Guided by my expertise in lncRNA transcription I recently identified the genetic material to dissect tTI in plants as an independent group leader. My planned research promises to reveal the genetic architecture and the molecular hallmarks defining tTI in higher organisms. Environmental lncRNA transcription variability may trigger tTI to promote organismal responses to changing conditions. We will address the roles of tTI in plant cold response to test this hypothesis. I anticipate our findings to inform on the fraction of pervasive transcription engaging in tTI. My proposal promises to advance our understanding of genomes by reconciling how the transcription of variable non-coding DNA sequences can elicit equivalent functions.
Summary
Genomic DNA represents the blueprint of life: it instructs solutions to challenges during life cycles of organisms. Curiously DNA in higher organisms is mostly non-protein coding (e.g. 97% in human). The popular “junk-DNA” hypothesis postulates that this non-coding DNA is non-functional. However, high-throughput transcriptomics indicates that this may be an over-simplification as most non-coding DNA is transcribed. This pervasive transcription yields two molecular events that may be functional: 1.) resulting long non-coding RNA (lncRNA) molecules, and 2.) the act of pervasive transcription itself. Whereas lncRNA sequences and functions differ on a case-by-case basis, RNA polymerase II (Pol II) transcribes most lncRNA. Pol II activity leaves molecular marks that specify transcription stages. The profiles of stage-specific activities instruct separation and fidelity of transcription units (genomic punctuation). Pervasive transcription affects genomic punctuation: upstream lncRNA transcription over gene promoters can repress downstream gene expression, also referred to as tandem Transcriptional Interference (tTI). Even though tTI was first reported decades ago a systematic characterization of tTI is lacking. Guided by my expertise in lncRNA transcription I recently identified the genetic material to dissect tTI in plants as an independent group leader. My planned research promises to reveal the genetic architecture and the molecular hallmarks defining tTI in higher organisms. Environmental lncRNA transcription variability may trigger tTI to promote organismal responses to changing conditions. We will address the roles of tTI in plant cold response to test this hypothesis. I anticipate our findings to inform on the fraction of pervasive transcription engaging in tTI. My proposal promises to advance our understanding of genomes by reconciling how the transcription of variable non-coding DNA sequences can elicit equivalent functions.
Max ERC Funding
1 499 952 €
Duration
Start date: 2018-02-01, End date: 2023-01-31
Project acronym QUANTUM-N
Project Quantum Mechanics in the Negative Mass Reference Frame
Researcher (PI) Eugene Simon Polzik
Host Institution (HI) KOBENHAVNS UNIVERSITET
Call Details Advanced Grant (AdG), PE2, ERC-2017-ADG
Summary A fundamental aspect of quantum mechanics is the balance between information and disturbance by the measurement. A textbook example is the measurement of a position of an object which imposes a random perturbation on its momentum. This perturbation, the quantum back action, translates with time into uncertainty of the motion trajectory. The PI has proposed an approach which allows for simultaneous measurements of arbitrary small disturbances in both the position and the momentum. It is based on a measurement performed in a quantum reference frame with an effective negative mass, or frequency for an oscillator. Recently the PI’s group has experimentally demonstrated the first step along this novel path - quantum back action evasion for the measurement of motion in a reference frame of a spin oscillator.
We propose a project which takes detection of motion to a new frontier. We will develop a novel hybrid quantum system involving disparate macroscopic objects, a mechanical oscillator and a reference spin oscillator with the effective negative mass. We will demonstrate quantum entanglement between the two oscillators and entanglement-enhanced sensing of force and acceleration. The technology for high quality mechanical and spin oscillators developed at the PI’s group will be further advanced towards those goals.
We will generate manifestly non-classical states of millimetre size mechanical oscillators and a macroscopic coherent superposition of distant spin and mechanical objects. We will furthermore work towards generation of multi-partite entangled states of spins, macroscopic objects, and photons, thus testing fundamental limits of entanglement and decoherence for large and complex systems.
Gravitational wave interferometers which have recently detected first gravitational waves are expected to be soon limited in their sensitivity by the quantum back action. The way to overcome this limit using the approach developed within this project will be explored.
Summary
A fundamental aspect of quantum mechanics is the balance between information and disturbance by the measurement. A textbook example is the measurement of a position of an object which imposes a random perturbation on its momentum. This perturbation, the quantum back action, translates with time into uncertainty of the motion trajectory. The PI has proposed an approach which allows for simultaneous measurements of arbitrary small disturbances in both the position and the momentum. It is based on a measurement performed in a quantum reference frame with an effective negative mass, or frequency for an oscillator. Recently the PI’s group has experimentally demonstrated the first step along this novel path - quantum back action evasion for the measurement of motion in a reference frame of a spin oscillator.
We propose a project which takes detection of motion to a new frontier. We will develop a novel hybrid quantum system involving disparate macroscopic objects, a mechanical oscillator and a reference spin oscillator with the effective negative mass. We will demonstrate quantum entanglement between the two oscillators and entanglement-enhanced sensing of force and acceleration. The technology for high quality mechanical and spin oscillators developed at the PI’s group will be further advanced towards those goals.
We will generate manifestly non-classical states of millimetre size mechanical oscillators and a macroscopic coherent superposition of distant spin and mechanical objects. We will furthermore work towards generation of multi-partite entangled states of spins, macroscopic objects, and photons, thus testing fundamental limits of entanglement and decoherence for large and complex systems.
Gravitational wave interferometers which have recently detected first gravitational waves are expected to be soon limited in their sensitivity by the quantum back action. The way to overcome this limit using the approach developed within this project will be explored.
Max ERC Funding
2 178 574 €
Duration
Start date: 2018-07-01, End date: 2023-06-30
Project acronym RYD-QNLO
Project Quantum nonlinear optics through Rydberg interaction
Researcher (PI) Sebastian HOFFERBERTH
Host Institution (HI) SYDDANSK UNIVERSITET
Call Details Consolidator Grant (CoG), PE2, ERC-2017-COG
Summary Optical photons, for all practical purposes, do not interact. This fundamental property of light forms the basis of modern optics and enables a multitude of technical applications in our every-day life, such as all-optical communication and microscopy. On the other hand, an engineered interaction between individual photons would allow the creation and control of light photon by photon, providing fundamental insights into the quantum nature of light and allowing us to harness non-classical states of light as resource for future technology. Mapping the strong interaction between Rydberg atoms onto individual photons has emerged as a highly promising approach towards this ambitious goal. In this project, we will advance and significantly broaden the research field of Rydberg quantum optics to develop new tools for realizing strongly correlated quantum many-body states of photons. Building on our successful work over recent years, we will greatly expand our control over Rydberg slow-light polaritons to implement mesoscopic systems of strongly interacting photons in an ultracold ytterbium gas. In parallel, we will explore a new approach to strong light-matter coupling, utilizing Rydberg superatoms made out of thousands of individual atoms, strongly coupled to a propagating light mode. This free-space QED system enables strong coupling between single photons and single artificial atoms in the optical domain without any confining structures for the light. Finally, we will experimentally realize a novel quantum hybrid system exploiting the strong electric coupling between single Rydberg atoms and piezo-electric micro-mechanical oscillators. Building on this unique coupling scheme, we will explore Rydberg-mediated cooling of a mechanical system and dissipative preparation of non-classical phonon states. The three complementary parts ultimately unite into a powerful Rydberg quantum optics toolbox which will provide unprecedented control over single photons and single phonons.
Summary
Optical photons, for all practical purposes, do not interact. This fundamental property of light forms the basis of modern optics and enables a multitude of technical applications in our every-day life, such as all-optical communication and microscopy. On the other hand, an engineered interaction between individual photons would allow the creation and control of light photon by photon, providing fundamental insights into the quantum nature of light and allowing us to harness non-classical states of light as resource for future technology. Mapping the strong interaction between Rydberg atoms onto individual photons has emerged as a highly promising approach towards this ambitious goal. In this project, we will advance and significantly broaden the research field of Rydberg quantum optics to develop new tools for realizing strongly correlated quantum many-body states of photons. Building on our successful work over recent years, we will greatly expand our control over Rydberg slow-light polaritons to implement mesoscopic systems of strongly interacting photons in an ultracold ytterbium gas. In parallel, we will explore a new approach to strong light-matter coupling, utilizing Rydberg superatoms made out of thousands of individual atoms, strongly coupled to a propagating light mode. This free-space QED system enables strong coupling between single photons and single artificial atoms in the optical domain without any confining structures for the light. Finally, we will experimentally realize a novel quantum hybrid system exploiting the strong electric coupling between single Rydberg atoms and piezo-electric micro-mechanical oscillators. Building on this unique coupling scheme, we will explore Rydberg-mediated cooling of a mechanical system and dissipative preparation of non-classical phonon states. The three complementary parts ultimately unite into a powerful Rydberg quantum optics toolbox which will provide unprecedented control over single photons and single phonons.
Max ERC Funding
1 993 793 €
Duration
Start date: 2018-05-01, End date: 2023-04-30
