Periodic Reporting for period 1 - ASPECTS (Quantum Thermodynamics of Precision in Electronic Devices)
Reporting period: 2022-11-01 to 2024-04-30
ASPECTS is an EU-funded consortium of scientists investigating the thermodynamics of precision measurement using quantum systems. Spanning five European countries, our partners collaborate to identify fundamental limits and reveal new design principles for energy-efficient and precise quantum measuring devices.
The burgeoning quantum technology revolution promises a paradigm shift in the way that we generate, process, and communicate information. Technologies such as quantum computation and quantum sensing are enabled by our ability to control and measure quantum systems with exquisite precision. Such precise measurement and control consume power, meaning that the large-scale deployment of quantum technologies will come at an increasingly large energetic and environmental cost. It is therefore vitally important to develop more energy-efficient devices for precise quantum measurement that can operate at the nanoscale.
Quantum technologies exploit the counterintuitive physics of the microscopic world to gain an advantage over purely classical systems. In order to achieve commercial usefulness, major research efforts are now devoted to scaling up current noisy intermediate-scale quantum
devices. The fundamental challenge to be overcome is noise, whose presence is necessitated by basic quantum and thermodynamic principles as well as limitations on the precision with which such devices can be measured and controlled. To overcome this challenge, we need to understand the fundamental thermodynamic limitations on precision in quantum devices. Remarkably, it has recently been predicted that coherent quantum processes exhibit a new kind of quantum advantage with respect to classical processes: the laws of quantum thermodynamics allow higher measurement precision for less energy and entropy cost. The ambitious goal of ASPECTS is to
demonstrate, explore, and exploit this novel effect on two of the most promising quantum technology platforms: namely, superconducting qubits and nanoelectromechanical devices. Specifically, we will design and build quantum circuit devices to experimentally assess the
energy cost of timekeeping and qubit readout. With support from advanced theory and numerical simulations, we will demonstrate quantum-thermodynamic precision advantage in our measurements. This ground-breaking advance will usher in a new paradigm for quantum metrology in which quantum-thermodynamic effects boost both efficiency and precision. Our balanced consortium of early career researchers is founded on our strong existing collaborations and our unified and coherent vision for the future of energy-efficient quantum technologies. Bringing together world-leading expertise in precision measurement, quantum information, and non-equilibrium statistical physics, ASPECTS will make a deep and lasting impact on the European quantum technologies landscape.
Our four objectives are:
To experimentally demonstrate the violation of the classical TUR in an open quantum system, i.e. measure an SNR below the classical TUR bound.
To build autonomous quantum clocks with NEMS and CQED devices and measure the energetic cost of timekeeping in the quantum domain, thus probing the ultimate thermodynamic limits on quantum clocks.
To construct two apparatuses to measure the state of a quantum bit using thermal noise, and thus measure the thermodynamic cost of qubit readout.
To implement the first proof-of-principle demonstration of a quantum-thermodynamic precision advantage, where a measuring device exploits a quantum-coherent process to achieve higher precision than would be classically possible for a given energy cost
The burgeoning quantum technology revolution promises a paradigm shift in the way that we generate, process, and communicate information. Technologies such as quantum computation and quantum sensing are enabled by our ability to control and measure quantum systems with exquisite precision. Such precise measurement and control consume power, meaning that the large-scale deployment of quantum technologies will come at an increasingly large energetic and environmental cost. It is therefore vitally important to develop more energy-efficient devices for precise quantum measurement that can operate at the nanoscale.
Quantum technologies exploit the counterintuitive physics of the microscopic world to gain an advantage over purely classical systems. In order to achieve commercial usefulness, major research efforts are now devoted to scaling up current noisy intermediate-scale quantum
devices. The fundamental challenge to be overcome is noise, whose presence is necessitated by basic quantum and thermodynamic principles as well as limitations on the precision with which such devices can be measured and controlled. To overcome this challenge, we need to understand the fundamental thermodynamic limitations on precision in quantum devices. Remarkably, it has recently been predicted that coherent quantum processes exhibit a new kind of quantum advantage with respect to classical processes: the laws of quantum thermodynamics allow higher measurement precision for less energy and entropy cost. The ambitious goal of ASPECTS is to
demonstrate, explore, and exploit this novel effect on two of the most promising quantum technology platforms: namely, superconducting qubits and nanoelectromechanical devices. Specifically, we will design and build quantum circuit devices to experimentally assess the
energy cost of timekeeping and qubit readout. With support from advanced theory and numerical simulations, we will demonstrate quantum-thermodynamic precision advantage in our measurements. This ground-breaking advance will usher in a new paradigm for quantum metrology in which quantum-thermodynamic effects boost both efficiency and precision. Our balanced consortium of early career researchers is founded on our strong existing collaborations and our unified and coherent vision for the future of energy-efficient quantum technologies. Bringing together world-leading expertise in precision measurement, quantum information, and non-equilibrium statistical physics, ASPECTS will make a deep and lasting impact on the European quantum technologies landscape.
Our four objectives are:
To experimentally demonstrate the violation of the classical TUR in an open quantum system, i.e. measure an SNR below the classical TUR bound.
To build autonomous quantum clocks with NEMS and CQED devices and measure the energetic cost of timekeeping in the quantum domain, thus probing the ultimate thermodynamic limits on quantum clocks.
To construct two apparatuses to measure the state of a quantum bit using thermal noise, and thus measure the thermodynamic cost of qubit readout.
To implement the first proof-of-principle demonstration of a quantum-thermodynamic precision advantage, where a measuring device exploits a quantum-coherent process to achieve higher precision than would be classically possible for a given energy cost
So far we have focussed mainly on the first two objectives of the project: demonstrating violation of classical TURs and assessing the cost of timekeeping in quantum systems.
On the theoretical side, we have been developing mathematical and computational methods to describe the fluctuations of currents in quantum systems far from equilibrium. We have introduced new techniques to understand and predict these fluctuations in a range of different settings, including in the presence of strong interactions between the quantum system and its surroundings. We have also derived new theoretical bounds on current fluctuations that take into account correlations between different currents, yielding tighter constraints in both classical and quantum systems. These results set the stage for our experimental objectives, providing a flexible predictive framework as well as new fundamental predictions to test in the lab.
On the experimental side, we have built the capability to measure the fluctuations of tiny heat currents (below the atto-Watt scale) in a circuit QED setup. This will enable us to observe TUR violations in open quantum systems for the first time. We have also performed a thorough thermodynamic analysis of a carbon nanotube, measuring work and entropy in this nanoscale system. Furthermore, we have constructed autonomous clocks using superconducting qubits and quantum dots. In both cases, we have measured elementary ticks corresponding to the exchange of individual quanta, and are currently analysing the connection between clock accuracy and entropy production.
On the theoretical side, we have been developing mathematical and computational methods to describe the fluctuations of currents in quantum systems far from equilibrium. We have introduced new techniques to understand and predict these fluctuations in a range of different settings, including in the presence of strong interactions between the quantum system and its surroundings. We have also derived new theoretical bounds on current fluctuations that take into account correlations between different currents, yielding tighter constraints in both classical and quantum systems. These results set the stage for our experimental objectives, providing a flexible predictive framework as well as new fundamental predictions to test in the lab.
On the experimental side, we have built the capability to measure the fluctuations of tiny heat currents (below the atto-Watt scale) in a circuit QED setup. This will enable us to observe TUR violations in open quantum systems for the first time. We have also performed a thorough thermodynamic analysis of a carbon nanotube, measuring work and entropy in this nanoscale system. Furthermore, we have constructed autonomous clocks using superconducting qubits and quantum dots. In both cases, we have measured elementary ticks corresponding to the exchange of individual quanta, and are currently analysing the connection between clock accuracy and entropy production.
Our theoretical results have substantially advanced the fields of counting statistics, the thermodynamics of precision, and the foundations of timekeeping. Our main experimental results are yet to be published.