Projects & Collaborations 27 foundShow per page10 10 20 50 Scalable High Bandwidth Quantum Network (sQnet) Research Project | 2 Project MembersRealizing a scalable quantum network is one of the grand challenges of quantum technology, with numerous potential applications in secure communication, quantum sensor networks, and distributed quantum computation. Single-photon sources and compatible quantum memories are key ingredients of quantum networks and the requirements on their performance are very stringent. In this project we will establish a scalable quantum networking platform that combines several high-performance elements: semiconductor quantum dot single-photon sources and compatible atomic vapor cell quantum memories implemented in scalable MEMS technology, operating with GHz bandwidth at convenient near-infrared wavelengths. Connectivity over long distance and to other platforms is enabled by efficient conversion of single photons to telecom wavelength using on-chip nonlinear optics. Combining these building blocks, we will demonstrate quantum networking tasks such as remote entanglement generation between quantum memories over a telecom fiber link. By demonstrating the basic functionality of a scalable quantum networking platform that operates at high efficiency and bandwidth, the project will lay the ground for the implementation of more advanced quantum networking protocols and scaling to multiple nodes. Potential of quantum sensing for precision metrology at METAS Research Project | 2 Project MembersIn the field of quantum sensing, new techniques have been developed that exploit quantum systems and their peculiar properties to enable new functionality and enhance accuracy and precision in a great variety of sensing applications. Researchers at the Department of Physics of the University of Basel have made important contributions to this field. The goal of this collaboration project is to evaluate the potential of quantum sensing techniques for metrology at METAS, the Swiss national metrology institute. Field sensing with atomic vapour cells Research Project | 1 Project MembersThe goal of the project is to explore potential commercial and industrial applications of electromagnetic field sensing with atomic vapour cells. LASERLOOP / Laser loop for engineering long-distance interactions in hybrid quantum systems Research Project | 2 Project MembersLight is a powerful carrier of quantum information and an established tool to manipulate matter at the quantum level. In this action, we explore a novel technique of using light in quantum physics and technology: As a means to generate for the first time strong, quantum coherent interactions between different systems over macroscopic distances. Our approach relies on a laser loop that connects the systems and mediates coherent bidirectional interactions between them. This is possible due to a destructive interference of the quantum noise introduced by the light, otherwise responsible for decoherence. At the same time, information is erased from the output field, making the loop effectively closed to the environment. This makes it possible to achieve quantum coherent coupling between the systems. QUSTEC PhD fellowship - Hybrid quantum networks with atomic memories and quantum dot single-photon sources Research Project | 1 Project MembersThis project aims at combining the high purity and large bandwidth of quantum dot single photons with the high efficiency and long storage times of atomic quantum memories into a hybrid quantum network architecture with advantageous properties. We already demonstrated that GaAs/AlGaAs quantum dots can emit transform-limited single photons tuned into resonance with rubidium atoms and that the temporal waveform of these photons can be controlled. In parallel, we realized a rubidium atomic quantum memory with a bandwidth of 660 MHz operating on the single-photon level. The goal of this project is to develop the two systems further and to interface them through an optical fiber link. Several improvements will be implemented to achieve low-noise operation: controlling the charge state of the dot and enhancing the photon collection efficiency with an optical cavity, as well as controlling the spin state of the atoms to suppress four-wave mixing noise by selection rules. After demonstrating storage and retrieval of quantum dot single photons in the atomic memory, we intend to perform basic quantum networking tasks with this hybrid system. Non-classical correlations in ultracold atomic ensembles Research Project | 1 Project MembersNon-classical correlations between quantum systems lead to the most striking departure of quantum from classical physics. Despite decades of research, such correlations still present many conceptual and experimental challenges, while at the same time their key role in quantum technologies is recognised. This is particularly true for systems of many particles, where different classes of non-classical states exist with different usefulness for technological tasks. There are open questions on how to generate, control, detect, and exploit non-classical correlations, in particular in large ensembles where access to individual particles is limited. To elucidate these questions has become a subject of intense research on different experimental platforms. Ultracold atomic ensembles are quantum many-particle systems par excellence: (1) atoms are very well isolated from the environment and feature long coherence times, (2) ensembles with adjustable atom number from a few hundreds to millions can be reliably generated, (3) a powerful toolbox for control and measurement of their quantum state is available, and (4) atom-atom interactions can be tuned and engineered to generate correlations in a controlled way. These unique features make ultracold atomic ensembles an ideal system for the experimental study of non-classical correlations in many-particle systems, which is the overarching goal of this project. We will use two complementary approaches to pursue this goal: In the first approach, we will investigate atomic two-component Bose-Einstein condensates on an atom chip. Non-classical correlations between the atomic spins are generated by controlled collisions in a state-dependent potential. A specific focus of the experiments will be the distribution of non-classical correlations from one to several spatially separated and individually addressable condensates, with the goal to demonstrate entanglement and Einstein-Podolsky-Rosen steering and to investigate schemes for interferometry with spatially split condensates near the atom chip surface. In the second approach we will explore a new scheme for generating non-classical correlations in large atomic spin ensembles based on light-mediated Hamiltonian interactions. Using a new experimental setup with ultracold atoms in an optical dipole trap, we will generate collective spin-spin interactions by multi-pass atom-light interactions with free-space laser beams. This scheme is promising for quantum manipulation of large atomic ensembles in a simple geometry, potentially interesting for precision metrology. This project is expected to lead to novel insights into generation and control of non-classical correlations in ultracold atomic ensembles, their distribution into spatially separated, individually controllable systems, and their use in quantum technologies, in particular sensing, metrology and imaging. MACQSIMAL - Miniature Atomic vapor Cells based Quantum devices for SensIng and Metrology AppLications Research Project | 1 Project MembersSensors provide the interface between the real world and the digital world. Quantum technologies are poised to revolutionize this interface, and with it sensor-driven industries such as navigation and medical imaging. MACQSIMAL combines the expertise of world-leading research groups, RTOs and companies, covering the whole knowledge chain from basic science to industrial deployment, and aims at breakthroughs that will firmly establish European leadership in the quantum sensor industry. MACQSIMAL will develop quantum-enabled sensors with outstanding sensitivity for five key physical observables: magnetic fields, time, rotation, electro-magnetic radiation and gas concentration. These sensors are chosen for their high impact and their potential to quickly advance to a product: Within MACQSIMAL all these sensors will reach TRLs between 3 and 6 and will outperform other solutions in the respective markets. The common core technology in these diverse sensors is atomic vapor cells realized as integrated microelectromechanical systems (MEMS). Atomic vapor cells make coherent quantum processes available to applications: advanced cell-based sensors optimally exploit single-particle coherence, with the potential to harness also multi-particle quantum coherence for still greater sensitivity. Fabricating such atomic vapor cells as MEMS allows for high-volume, high-reliability and low-cost deployment of miniaturized, integrated sensors, critical to wide-spread adoption. MACQSIMAL will combine state-of-the-art sensor physics with the MEMS atomic vapor cell platform, for highly advanced prototypes and demonstrators. Concurrently, advanced squeezing, entanglement and cavity-QED methods will be applied for the first time in miniaturized sensors, bringing quantum enhancement closer than ever to industrial application. This advanced, multi-target, quantum-enabled sensor platform will mark the start of a dynamic and multi-sector quantum sensor industry in Europe. Quantum Internet Alliance QIA Research Project | 2 Project MembersOUR GOAL IS TO DEVELOP A BLUEPRINT FOR A PAN-EUROPEAN ENTANGLEMENT-BASED QUANTUM INTERNET, BY DEVELOPING, INTEGRATING AND DEMONSTRATING ALL THE FUNCTIONAL HARDWARE AND SOFTWARE SUBSYSTEMS. Bell correlations in Bose-Einstein condensates Research Project | 2 Project MembersIn 1964, J. Bell discovered that the parts of a composite quantum system can show correlations that are stronger than any local realist theory allows. The existence of these Bell correlations has profound implications for the foundations of physics and at the same time underpins a variety of quantum information technologies that are currently being developed. While Bell correlations have been observed in systems of at most a few (usually two) particles, their role in many-body systems is largely unexplored. There are many open questions on how to create, detect and quantify Bell correlations in many-body systems, on their use in quantum technology, and on the connection between Bell correlations and many-particle entanglement. In this project, we will use atomic Bose-Einstein condensates on an atom chip - an exceptionally well-controlled quantum many-body system - for experiments on Bell correlations and many-particle entanglement and their application in quantum technology. In a recent breakthrough, the applicant's group reported the first observation of Bell correlations in a many-body system. Based on this result, we will study in depth the character of these correlations between atoms in a Bose-Einstein condensate. We will develop and test improved Bell correlation witnesses, including those that detect genuine many-particle Bell correlations, and aim at closing the statistics loophole. We will explore the possibility of performing a device-independent Bell test with hundreds of atoms. Moreover, we will investigate the use of Bell correlations in many-body systems for quantum information tasks. In previous experiments, entanglement and Bell correlations were detected between atoms in the same cloud, by performing global manipulations and measurements on the entire atomic ensemble. In this project we will go further and perform experiments with two spatially separated, individually addressable Bose-Einstein condensates. Based on a recent proposal, we will explore the generation of Einstein-Podolsky-Rosen (EPR) entanglement between the two condensates through collisions in a state-dependent potential. Such EPR entanglement is relevant for quantum metrology, because it allows to predict the outcome of spin measurements in one cloud conditioned on a corresponding measurement in the other cloud with higher precision than what is allowed by a naive application of the Heisenberg uncertainty relation. In the next step, we will explore Bell correlations between the two separate Bose-Einstein condensates, where the nonlocal character of these correlations can be directly revealed. We will explore the possibility of directly violating a Bell inequality with the two condensates in a device-independent way. The main applicant, Prof. Dr. Philipp Treutlein, is a young associate professor in the Department of Physics at the University of Basel. During the past five years, he and his team set up an experiment that offers exceptional control over the quantum state of mesoscopic Bose-Einstein condensates. The atoms are trapped and manipulated using a microfabricated atom chip, a powerful technique that no other experiment in Switzerland is currently using. A series of experimental results on spin-squeezing, entanglement, quantum metrology, and Bell correlations have been obtained with this setup. Experimental studies of Bell correlations in many-body systems are just beginning, and many open questions remain to be investigated. Building on the promising initial results obtained recently by the applicant's group, the goal of the present proposal is to explore this uncharted territory further. In 1964, J. Bell discovered that the parts of a composite quantum system can show correlations that are stronger than any local realist theory allows. The existence of these Bell correlations has profound implications for the foundations of physics and at the same time underpins a variety of quantum information technologies that are currently being developed. While Bell correlations have been observed in systems of at most a few (usually two) particles, their role in many-body systems is largely unexplored. There are many open questions on how to create, detect and quantify Bell correlations in many-body systems, on their use in quantum technology, and on the connection between Bell correlations and many-particle entanglement. In this project, we will use atomic Bose-Einstein condensates on an atom chip - an exceptionally well-controlled quantum many-body system - for experiments on Bell correlations and many-particle entanglement and their application in quantum technology. Theoretical investigations of Bell tests with a split BEC Research Project | 2 Project MembersWhile Bell tests have been initially proposed to show that correlations cannot be explained by local strategies, they are nowadays seen as trustworthy techniques - techniques which do not need a detailed description of experimental setups - to certify the presence of entanglement or to generate truly random bit strings. Bell tests, however, have been implemented on small systems only, involving at most 14 ions or 4 photons, and implementation in many-body systems has thus become a central challenge in quantum information theory. In this project we carry out theoretical studies aiming to provide a detailed recipe to realize the first Bell test using a split Bose-Einstein condensate made up of hundreds of pseudo-spin-1/2 bosons. 123 123
Scalable High Bandwidth Quantum Network (sQnet) Research Project | 2 Project MembersRealizing a scalable quantum network is one of the grand challenges of quantum technology, with numerous potential applications in secure communication, quantum sensor networks, and distributed quantum computation. Single-photon sources and compatible quantum memories are key ingredients of quantum networks and the requirements on their performance are very stringent. In this project we will establish a scalable quantum networking platform that combines several high-performance elements: semiconductor quantum dot single-photon sources and compatible atomic vapor cell quantum memories implemented in scalable MEMS technology, operating with GHz bandwidth at convenient near-infrared wavelengths. Connectivity over long distance and to other platforms is enabled by efficient conversion of single photons to telecom wavelength using on-chip nonlinear optics. Combining these building blocks, we will demonstrate quantum networking tasks such as remote entanglement generation between quantum memories over a telecom fiber link. By demonstrating the basic functionality of a scalable quantum networking platform that operates at high efficiency and bandwidth, the project will lay the ground for the implementation of more advanced quantum networking protocols and scaling to multiple nodes.
Potential of quantum sensing for precision metrology at METAS Research Project | 2 Project MembersIn the field of quantum sensing, new techniques have been developed that exploit quantum systems and their peculiar properties to enable new functionality and enhance accuracy and precision in a great variety of sensing applications. Researchers at the Department of Physics of the University of Basel have made important contributions to this field. The goal of this collaboration project is to evaluate the potential of quantum sensing techniques for metrology at METAS, the Swiss national metrology institute.
Field sensing with atomic vapour cells Research Project | 1 Project MembersThe goal of the project is to explore potential commercial and industrial applications of electromagnetic field sensing with atomic vapour cells.
LASERLOOP / Laser loop for engineering long-distance interactions in hybrid quantum systems Research Project | 2 Project MembersLight is a powerful carrier of quantum information and an established tool to manipulate matter at the quantum level. In this action, we explore a novel technique of using light in quantum physics and technology: As a means to generate for the first time strong, quantum coherent interactions between different systems over macroscopic distances. Our approach relies on a laser loop that connects the systems and mediates coherent bidirectional interactions between them. This is possible due to a destructive interference of the quantum noise introduced by the light, otherwise responsible for decoherence. At the same time, information is erased from the output field, making the loop effectively closed to the environment. This makes it possible to achieve quantum coherent coupling between the systems.
QUSTEC PhD fellowship - Hybrid quantum networks with atomic memories and quantum dot single-photon sources Research Project | 1 Project MembersThis project aims at combining the high purity and large bandwidth of quantum dot single photons with the high efficiency and long storage times of atomic quantum memories into a hybrid quantum network architecture with advantageous properties. We already demonstrated that GaAs/AlGaAs quantum dots can emit transform-limited single photons tuned into resonance with rubidium atoms and that the temporal waveform of these photons can be controlled. In parallel, we realized a rubidium atomic quantum memory with a bandwidth of 660 MHz operating on the single-photon level. The goal of this project is to develop the two systems further and to interface them through an optical fiber link. Several improvements will be implemented to achieve low-noise operation: controlling the charge state of the dot and enhancing the photon collection efficiency with an optical cavity, as well as controlling the spin state of the atoms to suppress four-wave mixing noise by selection rules. After demonstrating storage and retrieval of quantum dot single photons in the atomic memory, we intend to perform basic quantum networking tasks with this hybrid system.
Non-classical correlations in ultracold atomic ensembles Research Project | 1 Project MembersNon-classical correlations between quantum systems lead to the most striking departure of quantum from classical physics. Despite decades of research, such correlations still present many conceptual and experimental challenges, while at the same time their key role in quantum technologies is recognised. This is particularly true for systems of many particles, where different classes of non-classical states exist with different usefulness for technological tasks. There are open questions on how to generate, control, detect, and exploit non-classical correlations, in particular in large ensembles where access to individual particles is limited. To elucidate these questions has become a subject of intense research on different experimental platforms. Ultracold atomic ensembles are quantum many-particle systems par excellence: (1) atoms are very well isolated from the environment and feature long coherence times, (2) ensembles with adjustable atom number from a few hundreds to millions can be reliably generated, (3) a powerful toolbox for control and measurement of their quantum state is available, and (4) atom-atom interactions can be tuned and engineered to generate correlations in a controlled way. These unique features make ultracold atomic ensembles an ideal system for the experimental study of non-classical correlations in many-particle systems, which is the overarching goal of this project. We will use two complementary approaches to pursue this goal: In the first approach, we will investigate atomic two-component Bose-Einstein condensates on an atom chip. Non-classical correlations between the atomic spins are generated by controlled collisions in a state-dependent potential. A specific focus of the experiments will be the distribution of non-classical correlations from one to several spatially separated and individually addressable condensates, with the goal to demonstrate entanglement and Einstein-Podolsky-Rosen steering and to investigate schemes for interferometry with spatially split condensates near the atom chip surface. In the second approach we will explore a new scheme for generating non-classical correlations in large atomic spin ensembles based on light-mediated Hamiltonian interactions. Using a new experimental setup with ultracold atoms in an optical dipole trap, we will generate collective spin-spin interactions by multi-pass atom-light interactions with free-space laser beams. This scheme is promising for quantum manipulation of large atomic ensembles in a simple geometry, potentially interesting for precision metrology. This project is expected to lead to novel insights into generation and control of non-classical correlations in ultracold atomic ensembles, their distribution into spatially separated, individually controllable systems, and their use in quantum technologies, in particular sensing, metrology and imaging.
MACQSIMAL - Miniature Atomic vapor Cells based Quantum devices for SensIng and Metrology AppLications Research Project | 1 Project MembersSensors provide the interface between the real world and the digital world. Quantum technologies are poised to revolutionize this interface, and with it sensor-driven industries such as navigation and medical imaging. MACQSIMAL combines the expertise of world-leading research groups, RTOs and companies, covering the whole knowledge chain from basic science to industrial deployment, and aims at breakthroughs that will firmly establish European leadership in the quantum sensor industry. MACQSIMAL will develop quantum-enabled sensors with outstanding sensitivity for five key physical observables: magnetic fields, time, rotation, electro-magnetic radiation and gas concentration. These sensors are chosen for their high impact and their potential to quickly advance to a product: Within MACQSIMAL all these sensors will reach TRLs between 3 and 6 and will outperform other solutions in the respective markets. The common core technology in these diverse sensors is atomic vapor cells realized as integrated microelectromechanical systems (MEMS). Atomic vapor cells make coherent quantum processes available to applications: advanced cell-based sensors optimally exploit single-particle coherence, with the potential to harness also multi-particle quantum coherence for still greater sensitivity. Fabricating such atomic vapor cells as MEMS allows for high-volume, high-reliability and low-cost deployment of miniaturized, integrated sensors, critical to wide-spread adoption. MACQSIMAL will combine state-of-the-art sensor physics with the MEMS atomic vapor cell platform, for highly advanced prototypes and demonstrators. Concurrently, advanced squeezing, entanglement and cavity-QED methods will be applied for the first time in miniaturized sensors, bringing quantum enhancement closer than ever to industrial application. This advanced, multi-target, quantum-enabled sensor platform will mark the start of a dynamic and multi-sector quantum sensor industry in Europe.
Quantum Internet Alliance QIA Research Project | 2 Project MembersOUR GOAL IS TO DEVELOP A BLUEPRINT FOR A PAN-EUROPEAN ENTANGLEMENT-BASED QUANTUM INTERNET, BY DEVELOPING, INTEGRATING AND DEMONSTRATING ALL THE FUNCTIONAL HARDWARE AND SOFTWARE SUBSYSTEMS.
Bell correlations in Bose-Einstein condensates Research Project | 2 Project MembersIn 1964, J. Bell discovered that the parts of a composite quantum system can show correlations that are stronger than any local realist theory allows. The existence of these Bell correlations has profound implications for the foundations of physics and at the same time underpins a variety of quantum information technologies that are currently being developed. While Bell correlations have been observed in systems of at most a few (usually two) particles, their role in many-body systems is largely unexplored. There are many open questions on how to create, detect and quantify Bell correlations in many-body systems, on their use in quantum technology, and on the connection between Bell correlations and many-particle entanglement. In this project, we will use atomic Bose-Einstein condensates on an atom chip - an exceptionally well-controlled quantum many-body system - for experiments on Bell correlations and many-particle entanglement and their application in quantum technology. In a recent breakthrough, the applicant's group reported the first observation of Bell correlations in a many-body system. Based on this result, we will study in depth the character of these correlations between atoms in a Bose-Einstein condensate. We will develop and test improved Bell correlation witnesses, including those that detect genuine many-particle Bell correlations, and aim at closing the statistics loophole. We will explore the possibility of performing a device-independent Bell test with hundreds of atoms. Moreover, we will investigate the use of Bell correlations in many-body systems for quantum information tasks. In previous experiments, entanglement and Bell correlations were detected between atoms in the same cloud, by performing global manipulations and measurements on the entire atomic ensemble. In this project we will go further and perform experiments with two spatially separated, individually addressable Bose-Einstein condensates. Based on a recent proposal, we will explore the generation of Einstein-Podolsky-Rosen (EPR) entanglement between the two condensates through collisions in a state-dependent potential. Such EPR entanglement is relevant for quantum metrology, because it allows to predict the outcome of spin measurements in one cloud conditioned on a corresponding measurement in the other cloud with higher precision than what is allowed by a naive application of the Heisenberg uncertainty relation. In the next step, we will explore Bell correlations between the two separate Bose-Einstein condensates, where the nonlocal character of these correlations can be directly revealed. We will explore the possibility of directly violating a Bell inequality with the two condensates in a device-independent way. The main applicant, Prof. Dr. Philipp Treutlein, is a young associate professor in the Department of Physics at the University of Basel. During the past five years, he and his team set up an experiment that offers exceptional control over the quantum state of mesoscopic Bose-Einstein condensates. The atoms are trapped and manipulated using a microfabricated atom chip, a powerful technique that no other experiment in Switzerland is currently using. A series of experimental results on spin-squeezing, entanglement, quantum metrology, and Bell correlations have been obtained with this setup. Experimental studies of Bell correlations in many-body systems are just beginning, and many open questions remain to be investigated. Building on the promising initial results obtained recently by the applicant's group, the goal of the present proposal is to explore this uncharted territory further. In 1964, J. Bell discovered that the parts of a composite quantum system can show correlations that are stronger than any local realist theory allows. The existence of these Bell correlations has profound implications for the foundations of physics and at the same time underpins a variety of quantum information technologies that are currently being developed. While Bell correlations have been observed in systems of at most a few (usually two) particles, their role in many-body systems is largely unexplored. There are many open questions on how to create, detect and quantify Bell correlations in many-body systems, on their use in quantum technology, and on the connection between Bell correlations and many-particle entanglement. In this project, we will use atomic Bose-Einstein condensates on an atom chip - an exceptionally well-controlled quantum many-body system - for experiments on Bell correlations and many-particle entanglement and their application in quantum technology.
Theoretical investigations of Bell tests with a split BEC Research Project | 2 Project MembersWhile Bell tests have been initially proposed to show that correlations cannot be explained by local strategies, they are nowadays seen as trustworthy techniques - techniques which do not need a detailed description of experimental setups - to certify the presence of entanglement or to generate truly random bit strings. Bell tests, however, have been implemented on small systems only, involving at most 14 ions or 4 photons, and implementation in many-body systems has thus become a central challenge in quantum information theory. In this project we carry out theoretical studies aiming to provide a detailed recipe to realize the first Bell test using a split Bose-Einstein condensate made up of hundreds of pseudo-spin-1/2 bosons.
