



02007nas a2200181   4500008004100000245010800041210006900149260001500218520141700233100002201650700001901672700001901691700002001710700001901730700001701749700002201766856003701788       2023                        eng d00aA general approach to backaction-evading receivers with magnetomechanical and electromechanical sensors0 ageneral approach to backactionevading receivers with magnetomech  c11/16/20233 a<p>Today&#39;s mechanical sensors are capable of detecting extremely weak perturbations while operating near the standard quantum limit. However, further improvements can be made in both sensitivity and bandwidth when we reduce the noise originating from the process of measurement itself -- the quantum-mechanical backaction of measurement -- and go below this &#39;standard&#39; limit, possibly approaching the Heisenberg limit. One of the ways to eliminate this noise is by measuring a quantum nondemolition variable such as the momentum in a free-particle system. Here, we propose and characterize theoretical models for direct velocity measurement that utilize traditional electric and magnetic transducer designs to generate a signal while enabling this backaction evasion. We consider the general readout of this signal via electric or magnetic field sensing by creating toy models analogous to the standard optomechanical position-sensing problem, thereby facilitating the assessment of measurement-added noise. Using simple models that characterize a wide range of transducers, we find that the choice of readout scheme -- voltage or current -- for each mechanical detector configuration implies access to either the position or velocity of the mechanical sub-system. This in turn suggests a path forward for key fundamental physics experiments such as the direct detection of dark matter particles.</p>1 aRichman, Brittany1 aGhosh, Sohitri1 aCarney, Daniel1 aHiggins, Gerard1 aShawhan, Peter1 aLobb, C., J.1 aTaylor, Jacob, M.  uhttps://arxiv.org/abs/2311.0958701216nas a2200157   4500008004100000245005000041210005000091260001500141490000800156520078000164100001900944700001900963700002000982700001901002856003701021       2020                        eng d00aGravitational Direct Detection of Dark Matter0 aGravitational Direct Detection of Dark Matter  c10/13/20200 v1023 a<p>The only coupling dark matter is guaranteed to have with the standard model is through gravity. Here we propose a concept for direct dark matter detection using only this gravitational coupling, enabling a new regime of detection. Leveraging dramatic advances in the ability to create, maintain, and probe quantum states of massive objects, we suggest that an array of quantum-limited impulse sensors may be capable of detecting the correlated gravitational force created by a passing dark matter particle. We present two concrete realizations of this scheme, using either mechanical resonators or freely-falling masses. With currently available technology, a meter-scale apparatus of this type could detect any dark matter candidate around the Planck mass or heavier.</p>1 aCarney, Daniel1 aGhosh, Sohitri1 aKrnjaic, Gordan1 aTaylor, J., M.  uhttps://arxiv.org/abs/1903.00492