Fundamental Physics Test Apparatus

The next generation of space science and exploration will rely on exploiting quantum phenomena to push sensing precision beyond current limits. This subtopic seeks to advance technologies for ultra-precise measurements of fundamental constants and forces, gravity, inertia, electromagnetic fields, and time, which are essential to the search for new laws of physics and for deep-space navigation and exploration. The need is driven by NASA's unique requirements for rugged and low-Size, Weight, and Power (SWaP) systems leveraging quantum properties, including optical atomic clocks for next-level timekeeping and cold atom interferometers for precision inertial and gravitational sensing in microgravity. These technologies could also benefit from entanglement-enhanced measurement techniques and quantum memories to achieve precision beyond the standard quantum limit and to incorporate instruments into quantum-networks. Recent developments of laser control and manipulation of atoms have led to new types of quantum sensors and clocks. Atomic systems, being intrinsically quantum mechanical, have demonstrated their unique advantages in metrology and sensing. Perhaps the most celebrated atomic metrology tool is the atomic clock. Recently, atomic clocks in the optical frequency domain (i.e., optical primary frequency standards) have been matured to achieve frequency uncertainty beyond 1 part in 1018, far exceeding that of the primary Cesium standards. Similarly, Dopplersensitive quantum measurements of atomic particles lead to exquisite inertial sensors, exemplified by atom interferometers. Because the center of mass motion is involved, atom interferometers use atomic particles as test masses and quantum matter-wave interferometry for motional and force measurements. Indeed, optical clocks and atom interferometers are two sides of the same coin, sharing many common physical processes, technologies, and salient performance features. For many measurements, the sensitivity scales strongly with the interaction time with an atom. As the atomic free fall time can be dramatically longer in microgravity, coupled with advanced cooling techniques which are optimized in the absence of gravity, these technologies are a natural fit for space exploration. Improved spaceborne quantum systems could enable spaceborne apparatuses to perform important fundamental physics experiments, including searching for local signatures of dark matter and dark energy, searching for time variations of fundamental constants, and precision tests of the foundational theories of modern physics including general relativity and quantum mechanics. However, maturing the technologies of spaceborne optical clocks and atom interferometers will also be impactful for application including timing and inertial navigation, planetary sciences, and gravity, atmosphere, and mass-change sensing. Maturing entanglementenhanced sensors and quantum memories for space will also be important to realize quantum-networked sensors for exploring fundamental physics in space. With this broad range of possible applications and missions, the purpose of this proposal calls to specifically solicit the development of compact, space qualifiable subsystems common to atom interferometers, atomic clocks, and quantum gas systems including high-flux cold atom sources, lasers and optical distribution systems, highly stable current sources for rapidly switching inductive loads, and optical frequency combs. Proposals are expected to address specific critical gaps identified. Note that Rydberg-atom based sensors should go to INSTALG.5.S26B. Note that quantum sensing for space weather should go to SPWX.3.T26B. Note that superconducting detectors should go to INSTALG.4.S26B or COSMO.1.S26A depending on wavelength.