01763nas a2200169 4500008004100000245007700041210006900118260001500187490000600202520123700208100002101445700002601466700002101492700001901513700002401532856003701556 2022 eng d00aTheoretical bounds on data requirements for the ray-based classification0 aTheoretical bounds on data requirements for the raybased classif c02/26/20220 v33 a

The problem of classifying high-dimensional shapes in real-world data grows in complexity as the dimension of the space increases. For the case of identifying convex shapes of different geometries, a new classification framework has recently been proposed in which the intersections of a set of one-dimensional representations, called rays, with the boundaries of the shape are used to identify the specific geometry. This ray-based classification (RBC) has been empirically verified using a synthetic dataset of two- and three-dimensional shapes [1] and, more recently, has also been validated experimentally [2]. Here, we establish a bound on the number of rays necessary for shape classification, defined by key angular metrics, for arbitrary convex shapes. For two dimensions, we derive a lower bound on the number of rays in terms of the shape's length, diameter, and exterior angles. For convex polytopes in R^N, we generalize this result to a similar bound given as a function of the dihedral angle and the geometrical parameters of polygonal faces. This result enables a different approach for estimating high-dimensional shapes using substantially fewer data elements than volumetric or surface-based approaches.

1 aWeber, Brian, J.1 aKalantre, Sandesh, S.1 aMcJunkin, Thomas1 aTaylor, J., M.1 aZwolak, Justyna, P. uhttps://arxiv.org/abs/2103.0957701337nas a2200157 4500008004100000245005300041210005300094260001300147490000800160520089300168100001901061700002201080700002101102700001901123856003701142 2021 eng d00aTrapped electrons and ions as particle detectors0 aTrapped electrons and ions as particle detectors c8/5/20210 v1273 a

Electrons and ions trapped with electromagnetic fields have long served as important high-precision metrological instruments, and more recently have also been proposed as a platform for quantum information processing. Here we point out that these systems can also be used as highly sensitive detectors of passing charged particles, due to the combination of their extreme charge-to-mass ratio and low-noise quantum readout and control. In particular, these systems can be used to detect energy depositions many orders of magnitude below typical ionization scales. As an illustration, we show that current devices can be used to provide competitive sensitivity to models where ambient dark matter particles carry small electric millicharges ≪e. Our calculations may also be useful in the characterization of noise in quantum computers coming from backgrounds of charged particles.

1 aCarney, Daniel1 aHäffner, Hartmut1 aMoore, David, C.1 aTaylor, J., M. uhttps://arxiv.org/abs/2104.0573701154nas a2200121 4500008004100000245006200041210006000103520076900163100001900932700002500951700001900976856003700995 2018 eng d00aTabletop experiments for quantum gravity: a user's manual0 aTabletop experiments for quantum gravity a users manual3 a

Recent advances in cooling, control, and measurement of mechanical systems in the quantum regime have opened the possibility of the first direct observation of quantum gravity, at scales achievable in experiments. This paper gives a broad overview of this idea, using some matter-wave and optomechanical systems to illustrate the predictions of a variety of models of low-energy quantum gravity. We first review the treatment of perturbatively quantized general relativity as an effective quantum field theory, and consider the particular challenges of observing quantum effects in this framework. We then move on to a variety of alternative models, such as those in which gravity is classical, emergent, or responsible for a breakdown of quantum mechanics.

1 aCarney, Daniel1 aStamp, Philip, C. E.1 aTaylor, J., M. uhttps://arxiv.org/abs/1807.1149401154nas a2200121 4500008004100000245006200041210006000103520076900163100001900932700002500951700001900976856003700995 2018 eng d00aTabletop experiments for quantum gravity: a user's manual0 aTabletop experiments for quantum gravity a users manual3 a

Recent advances in cooling, control, and measurement of mechanical systems in the quantum regime have opened the possibility of the first direct observation of quantum gravity, at scales achievable in experiments. This paper gives a broad overview of this idea, using some matter-wave and optomechanical systems to illustrate the predictions of a variety of models of low-energy quantum gravity. We first review the treatment of perturbatively quantized general relativity as an effective quantum field theory, and consider the particular challenges of observing quantum effects in this framework. We then move on to a variety of alternative models, such as those in which gravity is classical, emergent, or responsible for a breakdown of quantum mechanics.

1 aCarney, Daniel1 aStamp, Philip, C. E.1 aTaylor, J., M. uhttps://arxiv.org/abs/1807.1149401333nas a2200169 4500008004100000245008100041210006900122260001500191300001100206490000700217520083100224100002001055700001501075700001701090700001901107856003701126 2017 eng d00aThermodynamic limits for optomechanical systems with conservative potentials0 aThermodynamic limits for optomechanical systems with conservativ c2017/11/13 a1841060 v963 a

The mechanical force from light – radiation pressure – provides an intrinsic nonlinear interaction. Consequently, optomechanical systems near their steady state, such as the canonical optical spring, can display non-analytic behavior as a function of external parameters. This non-analyticity, a key feature of thermodynamic phase transitions, suggests that there could be an effective thermodynamic description of optomechanical systems. Here we explicitly define the thermodynamic limit for optomechanical systems and derive a set of sufficient constraints on the system parameters as the mechanical system grows large. As an example, we show how these constraints can be satisfied in a system with Z2 symmetry and derive a free energy, allowing us to characterize this as an equilibrium phase transition.

1 aRagole, Stephen1 aXu, Haitan1 aLawall, John1 aTaylor, J., M. uhttps://arxiv.org/abs/1707.0577101530nas a2200217 4500008004100000245006000041210006000101260001500161300001100176490000800187520092200195100001501117700001601132700001601148700001101164700001901175700002101194700001901215700001801234856006001252 2017 eng d00aThreshold Dynamics of a Semiconductor Single Atom Maser0 aThreshold Dynamics of a Semiconductor Single Atom Maser c2017/08/31 a0977020 v1193 a

We demonstrate a single atom maser consisting of a semiconductor double quantum dot (DQD) that is embedded in a high-quality-factor microwave cavity. A finite bias drives the DQD out of equilibrium, resulting in sequential single electron tunneling and masing. We develop a dynamic tuning protocol that allows us to controllably increase the time-averaged repumping rate of the DQD at a fixed level detuning, and quantitatively study the transition through the masing threshold. We further examine the crossover from incoherent to coherent emission by measuring the photon statistics across the masing transition. The observed threshold behavior is in agreement with an existing single atom maser theory when small corrections from lead emission are taken into account.

1 aLiu, Y.-Y.1 aStehlik, J.1 aEichler, C.1 aMi, X.1 aHartke, T., R.1 aGullans, Michael1 aTaylor, J., M.1 aPetta, J., R. uhttps://link.aps.org/doi/10.1103/PhysRevLett.119.09770201158nas a2200157 4500008004100000245007300041210006900114260001500183300001100198490000800209520069800217100001800915700001100933700001900944856003700963 2015 eng d00aTunable Spin Qubit Coupling Mediated by a Multi-Electron Quantum Dot0 aTunable Spin Qubit Coupling Mediated by a MultiElectron Quantum  c2015/06/04 a2268030 v1143 aWe present an approach for entangling electron spin qubits localized on spatially separated impurity atoms or quantum dots via a multi-electron, two-level quantum dot. The effective exchange interaction mediated by the dot can be understood as the simplest manifestation of Ruderman-Kittel-Kasuya-Yosida exchange, and can be manipulated through gate voltage control of level splittings and tunneling amplitudes within the system. This provides both a high degree of tuneability and a means for realizing high-fidelity two-qubit gates between spatially separated spins, yielding an experimentally accessible method of coupling donor electron spins in silicon via a hybrid impurity-dot system. 1 aSrinivasa, V.1 aXu, H.1 aTaylor, J., M. uhttp://arxiv.org/abs/1312.1711v3