With thermal fluctuation strongly suppressed,low temperature environment is essential for studies of condensed matter physics and developments of quantum technologies.Ultra-low temperature below 20 m K has demonstrate...With thermal fluctuation strongly suppressed,low temperature environment is essential for studies of condensed matter physics and developments of quantum technologies.Ultra-low temperature below 20 m K has demonstrated its importance and significance in physical sciences and information techniques.Dilution refrigeration is by far the best feasible and reliable method to generate and keep lattice temperature in this range.With a potential shortage of helium supply,cryogen-free dilution refrigerator(CFDR),eliminating the necessity of regular helium refill,becomes the main facility for the purpose of creating ultralow temperature environments.Here we describe our successful construction of a CFDR which reached a base temperature of around 10.9 m K for continuous circulation and 8.6 m K for single-shot operation.We describe its operating mechanism and the designs of key components,especially some unique designs including heat switch and alumina thermal link.Possible improvements in the future are also discussed.展开更多
Solid-state quantum computation station belongs to the group 2 of manipulation of quantum state in the Synergetic Extreme Condition User Facility. Here we will first outline the research background, aspects, and objec...Solid-state quantum computation station belongs to the group 2 of manipulation of quantum state in the Synergetic Extreme Condition User Facility. Here we will first outline the research background, aspects, and objectives of the station, followed by a discussion of the recent scientific as well as technological progress in this field based on similar experimental facilities to be constructed in the station. Finally, a brief summary and research perspective will be presented.展开更多
Possible light bosonic dark matter interactions with the Standard Model photon have been searched using microwave resonant cavities.In this paper,we describe the cryogenic readout system calibration of a 7.138 GHz cop...Possible light bosonic dark matter interactions with the Standard Model photon have been searched using microwave resonant cavities.In this paper,we describe the cryogenic readout system calibration of a 7.138 GHz copper cavity with a loaded quality factor Q_(1)=10^(4)whose operation at a temperature of 22 mK is based on a dilution refrigerator.Our readout system consists of High Electron Mobility Transistors working as cryogenic amplifiers at 4 K,plus room-temperature amplifiers and a spectrum analyzer for signal power detection.We tested the system with a superconducting two-level system based on a single-photon source in the microwave frequency regime.We obtained an overall 95.6 dB system gain and–71.4 dB attenuation in the cavity's input channel.The effective noise temperature of the measurement system is 7.5 K.展开更多
Dark photons,as a minimal extension of the Standard Model through an additional Abelian gauge group,may propagate relativistically across the galaxy,originating from dark matter decay or annihilation,thereby contribut...Dark photons,as a minimal extension of the Standard Model through an additional Abelian gauge group,may propagate relativistically across the galaxy,originating from dark matter decay or annihilation,thereby contributing to a galactic dark photon background.The generation of dark photons typically favors certain polarization modes,which are dependent on the interactions between dark matter and dark photons.We introduce a framework in which a resonant cavity is utilized to detect and differentiate these polarizations,leveraging the daily variation in expected signals due to the anisotropic distribution of dark photons and the rotation of the Earth.We conduct an experimental search using superconducting radio-frequency cavities,noted for their exceptionally high quality factors,proving them to be effective telescopes for observing galactic dark photons.This approach establishes the most stringent limits yet on the kinetic mixing coefficient between dark photons and electromagnetic photons,thereby unveiling a novel avenue for the indirect search for dark matter via multi-messenger astronomy.展开更多
基金supported by Key Research Program of Frontier Sciences,CAS(Grant No.ZDBS-LY-SLH0010)Beijing Natural Science Foundation(Grant No.JQ21002)Beijing Council of Science and Technology(Grant Nos.Z201100008420006 and Z211100004021012)
文摘With thermal fluctuation strongly suppressed,low temperature environment is essential for studies of condensed matter physics and developments of quantum technologies.Ultra-low temperature below 20 m K has demonstrated its importance and significance in physical sciences and information techniques.Dilution refrigeration is by far the best feasible and reliable method to generate and keep lattice temperature in this range.With a potential shortage of helium supply,cryogen-free dilution refrigerator(CFDR),eliminating the necessity of regular helium refill,becomes the main facility for the purpose of creating ultralow temperature environments.Here we describe our successful construction of a CFDR which reached a base temperature of around 10.9 m K for continuous circulation and 8.6 m K for single-shot operation.We describe its operating mechanism and the designs of key components,especially some unique designs including heat switch and alumina thermal link.Possible improvements in the future are also discussed.
文摘Solid-state quantum computation station belongs to the group 2 of manipulation of quantum state in the Synergetic Extreme Condition User Facility. Here we will first outline the research background, aspects, and objectives of the station, followed by a discussion of the recent scientific as well as technological progress in this field based on similar experimental facilities to be constructed in the station. Finally, a brief summary and research perspective will be presented.
基金supported in part by the Scientific Instrument Developing Project of the Chinese Academy of Sciences(YJKYYQ20190049)the International Partnership Program of Chinese Academy of Sciences for Grand Challenges(112311KYSB20210012)+1 种基金the National Natural Science Foundation of China(12074117,92365209,12150010,11875062,11947302,12047503,12074117,61833010,12061131011,12150410317,11905149,12275333)the Beijing Natural Science Foundation(IS23025)。
文摘Possible light bosonic dark matter interactions with the Standard Model photon have been searched using microwave resonant cavities.In this paper,we describe the cryogenic readout system calibration of a 7.138 GHz copper cavity with a loaded quality factor Q_(1)=10^(4)whose operation at a temperature of 22 mK is based on a dilution refrigerator.Our readout system consists of High Electron Mobility Transistors working as cryogenic amplifiers at 4 K,plus room-temperature amplifiers and a spectrum analyzer for signal power detection.We tested the system with a superconducting two-level system based on a single-photon source in the microwave frequency regime.We obtained an overall 95.6 dB system gain and–71.4 dB attenuation in the cavity's input channel.The effective noise temperature of the measurement system is 7.5 K.
基金National Key Research and Development Program of China(2020YFC2201501)Yifan Chen was supported by VILLUM FONDEN(37766)+4 种基金Danish Research Foundation,and under the European Union’s H2020 ERC Advanced Grant“Black holes:gravitational engines of discovery”grant agreement(Gravitas–101052587)European Consortium for Astroparticle Theory in the form of an Exchange Travel Grant,and by FCT(Fundação para a Ciência e Tecnologia I.P,Portugal)(2022.01324.PTDC)Jing Shu was supported by the National Natural Science Foundation of China(12025507,12450006,and.12150015)Peking University under startup Grant(7101302974)State Key Laboratory of Nuclear Physics and Technology,Peking University(NPT2024ZX01).
文摘Dark photons,as a minimal extension of the Standard Model through an additional Abelian gauge group,may propagate relativistically across the galaxy,originating from dark matter decay or annihilation,thereby contributing to a galactic dark photon background.The generation of dark photons typically favors certain polarization modes,which are dependent on the interactions between dark matter and dark photons.We introduce a framework in which a resonant cavity is utilized to detect and differentiate these polarizations,leveraging the daily variation in expected signals due to the anisotropic distribution of dark photons and the rotation of the Earth.We conduct an experimental search using superconducting radio-frequency cavities,noted for their exceptionally high quality factors,proving them to be effective telescopes for observing galactic dark photons.This approach establishes the most stringent limits yet on the kinetic mixing coefficient between dark photons and electromagnetic photons,thereby unveiling a novel avenue for the indirect search for dark matter via multi-messenger astronomy.
