Search for: All records

The recent laser excitation of the 229Th isomeric transition in a solid-state host opens the door for a portable solid-state nuclear optical clock. However, at present, the vacuum-ultraviolet laser systems required for clock operation are not conducive to a fieldable form factor. Here, we propose a possible solution to this problem by using 229Th-doped nonlinear optical crystals, which would allow clock operation without a vacuum-ultraviolet laser system and without the need of maintaining the crystal under vacuum. We investigate electronic properties and thorium doping in BaMgF4 and BaZnF4 with density functional theory, predicting BaMgF4 to be the superior material, and evaluate the performance of a Th:BaMgF4 clock. 

A comparative vacuum ultraviolet spectroscopy study conducted at ISOLDE-CERN of the radiative decay of the ${}^{229m}\mathrm{Th}$nuclear clock isomer embedded in different host materials is reported. The ratio of the number of radiative decay photons and the number of ${}^{229m}\mathrm{Th}$embedded are determined for single crystalline ${\mathrm{CaF}}_2, {\mathrm{MgF}}_2, {\mathrm{LiSrAlF}}_6$, AlN, and amorphous ${\mathrm{SiO}}_2$. For the latter two materials, no radiative decay signal was observed and an upper limit of the ratio is reported. The radiative decay wavelength was determined in ${\mathrm{LiSrAlF}}_6$and ${\mathrm{CaF}}_2$, reducing its uncertainty by a factor of 2.5 relative to our previous measurement. This value is in agreement with the recently reported improved values from laser excitation. Published by the American Physical Society2025 

Despite constantly using energy and having extensive interactions with household appliances, people consistently mis-estimate the amount of energy that is used by home appliances. This poses major problems for conservation efforts, while also presenting an interesting case study in human perception. Since many forms of energy used are not directly perceptible, and since the amount of energy that is being used by an appliance is often difficult to infer from appearances alone, people often rely on cues. Some of these cues are more reliable than others and previous literature has investigated which of these cues people rely on. However, past literature has always studied these proximal cues in isolation— despite the fact that, during real-world perception, people are always integrating a variety of cues. Here, we investigate how people rely on a variety of cues, and how individual differences in the reliance on those cues predicts the ability to estimate home energy use.