We propose a compact atom interferometer to measure homogeneous constant forces guiding the arms via shortcuts to adiabatic paths.For a given sensitivity, which only depends on the space-time area of the guiding paths, the cycle time can be made fast without losing visibility.The atom is driven by spin-dependent trapping potentials moving in opposite directions, complemented by linear and time-dependent potentials that compensate the trap acceleration.Thus, the arm states are adiabatic in the moving frames and nonadiabatic in the laboratory frame.The trapping potentials may be anharmonic, e.g., optical lattices, and the interferometric phase does not depend on the initial motional state or on the pivot point for swaying the linear potentials.
We propose a compact atom interferometer to measure homogeneous constant forces guiding the arms via shortcuts to adiabatic paths.For a given sensitivity, which only depends on the space-time area of the guiding paths, the cycle time can be made fast without losing visibility.The atom is driven by spin-dependent trapping potentials moving in opposite directions, complemented by linear and time-dependent potentials that compensate the trap acceleration.Thus, the arm states are adiabatic in the moving frames and nonadiabatic in the laboratory frame.The trapping potentials may be anharmonic, e.g., optical lattices, and the interferometric phase does not depend on the initial motional state or on the pivot point for swaying the linear potentials.
We propose an interferometric measurement of weak forces using a single ion subjected to designed time-dependent spin-dependent forces. Explicit expressions of the relation between the unknown force and the final populations are found considering different scenarios, such as the weak force acting on two branches, acting on one branch, or having errors in the driving force. The flexibility to design the trap trajectories is used to minimize errors due to anharmonicities in the trap. The advantages of the approach are the use of geometrical phases, which provides stability, the possibility to design faster-than-adiabatic processes with sensitivity control, and the independence of the results on the motional states for the small-oscillations regime in which the effective potentials are purely harmonic.
We reviewand update schemes for different measurements using STA-mediated guided interferometry with a single trapped particle. STA stands for "shortcuts to adiabaticity", a set of techniques to achieve the results of adiabatic dynamics in shorter times. In the first scheme we presented a protocol aimed at detecting weak unknown forces. It consisted of a single ion trapped in a harmonic potential and driven by time-and-spin-dependent forces generated via off-resonant lasers. Our approach provided stability and the independence of the results on the motional states for the small-oscillations regime. We could, also, design faster-than-adiabatic processes with sensitivity control. However, it required a rotation of the trapping potential at the moment the experiment starts. A much more practical and broadly applicable design was then developed, where no rotation is involved. Here, a single atom is driven by two moving spin-dependent trapping potentials where we guide the arms of the interferometer via shortcuts to adiabatic paths. In this paper, in addition to a brief review of these two previous proposals, we revisit the first scheme and present a new protocol where the spin-dependent driving force is generated via a "shaken" optical lattice. This opens the possibility for additional interferometric measurements beyond an unknown force, for example, the mass of the trapped ion, while still preserving the advantages of the previously proposed method.
To increase the measured phase of an atom interferometer and improve its sensitivity, researchers attempt to increase the enclosed space-time area using two methods: creating larger separations between the interferometer arms and having longer evolution times. However, increasing the evolution time reduces the bandwidth that can be sampled, whereas decreasing the evolution time worsens the sensitivity. In this paper, we attempt to address this by proposing a setup for high-bandwidth applications, with improved overall sensitivity. This is realized by accelerating and holding the atoms using optical dipole traps. We find that accelerations of up to 103–105m/s2 can be achieved using acousto-optic deflectors to move the traps. By comparing the sensitivity of our approach to acceleration as a baseline to traditional atom interferometry, we find a substantial improvement to the state of the art. In the limit of appropriate beam and optics stabilization, sensitivities approaching ${10}^{\ensuremath{-}14}$ (m/s2)/Hz may be achievable at 1 Hz, while detection at 1 kHz with a sensitivity an order of magnitude better than traditional free-fall atom interferometers is possible with today's systems.
Sagnac interferometers with massive particles promise unique advantages in achieving high-precision measurements of rotation rates over their optical counterparts. Recent proposals and experiments are exploring nonballistic Sagnac interferometers where trapped atoms are transported along a closed path. This is achieved by using superpositions of internal quantum states and their control with state-dependent potentials. We address emergent questions regarding the dynamical behavior of Bose-Einstein condensates in such an interferometer and its impact on rotation sensitivity. We investigate complex dependencies on atomic interactions as well as trap geometries, rotation rates, and speed of operation. We find that temporal transport profiles obtained from a simple optimization strategy for noninteracting particles remain surprisingly robust also in the presence of interactions over a large range of realistic parameters. High sensitivities can be achieved for short interrogation times far from the adiabatic regime. This highlights a route to building fast and robust guided-ring Sagnac interferometers with fully trapped atoms.
Inertial navigation systems are vital for modern society, be it on airplanes or in the context of autonomous mobility. On the other hand atom interferometers are exquisite measurement devices for inertia in fundamental physics and field applications, but are mostly limited to measuring one inertial observable. By utilizing time averaged optical potentials, the ultra-cold atomic ensemble input to the interferometer can be prepared in nearly arbitrary fashion. This results in a boost of preparation speed and number of atoms in the interferometer by increasing the size of the trap to match the size of the pre-cooled ensemble for optimal loading. Successive fast reduction of the extend of the trap leads to optimal evaporation efficiency and leads to increased sensitivity of the device, due to reduced cycle time of the experiment and increased atom number. Beyond this, the technique allows for new sensor geometries via the creation of multiple single wells, allowing for differential atom interferometry with numerous simultaneous interferometers. In this thesis, the first matter-wave analogue of a classical accelerometer array is implemented via the creation of a 3 × 3 array of Bose-Einstein condensates, consisting of 3 × 105 atoms and spanning a total area of 1.6 mm2 . Successive manipulation of the matter-waves with atom optics, coherently addressing the momentum states of the ensembles, allows for splitting, redirecting and readout pulses, realizing Mach-Zehnder type atom interferometers. Correlation of the nine 1D-acceleration measurements output by the interferometers yields measurements of linear acceleration, Euler- and centrifugal acceleration. The estimated sensitivity limits per shot are 6 × 10−5m s−2 for linear acceleration, 0.19 rad s − 2 for rotational acceleration and 203 mrad s−1 for rotation rate and are mainly limited due to the short free fall time of the ensembles, constrained by the atom optics light field. The correlation also allowed to determine the rotation center, being close to the retro reflection mirror of the atom optics light field. Crucial for the realization of this measurement was the implementation of time averaged potentials as stated above, facilitated through two 2D acousto-optical deflectors and a software defined radio, allowing for generating the required RF-signals. The techniques to simultaneously load and evaporate multiple ensembles into distinct traps from a single cloud of cold atoms and subsequently enlarge the spacing between the ensembles with adiabatic transport ramps are of highest interest for e.g. the Very Long Baseline Atom Interferometer facility in Hannover. Due to the correlated outputs systematic errors, such as wave front abberations, can be nullified. Furthermore the scheme can be extended to 3D matter-wave arrays, fulfilling all requirements necessary for an autonomous inertial measurement unit.
Atom interferometry has proven both a powerful means for probing fundamental physics, and a promising technology for high-precision inertial sensing. However, their performance has been limited by the available interrogation time of atoms falling freely in Earth's gravitational field. Trapped geometries have thus been explored as a means to improve the sensitivity of atom interferometers, but attempts to date have suffered from decoherence caused by trap inhomogeneities. We have demonstrated a trapped atom interferometer with an unprecedented interrogation time of 20 seconds,1 achieved by trapping the interferometer in the resonant mode of an optical cavity. The cavity is instrumental to this advance, as it provides spatial mode filtering for the trapping potential. Because the interferometer is held with the arms vertically separated along the gravitational axis, a phase shift accumulates due to the gravitational potential energy difference between the arms. Moreover, this phase accumulates continuously during the hold time, providing an orders-of-magnitude greater immunity to vibrations than previous atom-interferometric gravimeters at the same sensitivity.