arXiv subjects

Katarzyna Krzyzanowska

Publications and source records attributed to Katarzyna Krzyzanowska.

3 recordsLinked to original sources

arXiv2023

A Gauge Field Theory of Coherent Matter Waves

A gauge field treatment of a current, oscillating at a fixed frequency, of interacting neutral atoms leads to a set of matter-wave duals to Maxwell's equations for the electromagnetic field. In contrast to electromagnetics, the velocity of propagation has a lower limit rather than upper limit and the wave impedance of otherwise free space is negative real-valued rather than 377 Ohms. Quantization of the field leads to the matteron, the gauge boson dual to the photon. Unlike the photon, the matteron is bound to an atom and carries negative rather than positive energy, causing the source of the current to undergo cooling. Eigenstates of the combined matter and gauge field annihilation operator define the coherent state of the matter-wave field, which exhibits classical coherence in the limit of large excitation.

quant-ph↗

arXiv2023

Matter Wave Analog of a Fiber-Optic Gyroscope

Confining the propagating wavepackets of an atom interferometer inside a waveguide can substantially reduce the size of the device while preserving high sensitivity. We have realized a two-dimensional Sagnac atom interferometer in which Bose-condensed $^{87}$Rb atoms propagate within a tight waveguide formed by a collimated laser beam, a matter wave analog of the fiber optic gyro (FOG). The condensate is split, reflected, and recombined with a series of Bragg pulses while the waveguide moves transversely so that the wavepacket trajectories enclose an area. Delta-kick cooling is used to prepare low-density atomic wavepackets with a temperature of \SI{3}{\nano \kelvin}. The low density reduces the impact of interatomic interactions, while the low temperature limits the expansion of the wavepacket during the interferometer cycle. The effective enclosed area is $0.8 \text{mm}^2$ with an average fringe contrast of 20\% and underlying contrast up to 60\%. The main source of the reduced average contrast is phase noise caused by mechanical vibrations of the optical components. We present the first measurement of Allan deviation for such an atom rotation sensor, showing that the interferometer phase noise falls with averaging time $τ$ as $τ^{-1/2}$ for $τ$ up to 10,000 seconds. The statistical noise falls below the Earth rotation rate after 30 minutes of averaging.

physics.atom-ph↗

arXiv2022

One second interrogation time in a 200 round-trip waveguide atom interferometer

We report a multiple-loop guided atom interferometer in which the atoms make 200 small-amplitude roundtrips, instead of one large single orbit. The approach is enabled by using ultracold 39K gas and a magnetic Feshbach resonance that can tune the s-wave scattering length across zero to significantly reduce the atom loss from cold collisions. This scheme is resilient against noisy environments, achieving 0.9 s interrogation time without any vibration noise isolation or cancellation. A form of quantum lock-in amplification can be used with the device to measure localized potentials with high sensitivity. We used this technique to measure the dynamic polarizability of the 39K ground state at 1064 nm. The interferometer may also be a useful approach to building a compact multiple-loop Sagnac atom interferometer for rotation sensing.

physics.atom-ph↗