In this paper, we show how random fluctuations in the magnetic field gradient jitter the paths of a matter-wave interferometer randomly, hence, decohere the quantum superposition. To create a large spatial superposition with nanoparticles, we envisage embedding a spin in a nanoparticle as a defect and applying an inhomogeneous magnetic field as in a Stern-Gerlach-type experiment to create a macroscopic quantum superposition. Such matter-wave interferometers are the cornerstone for many new fundamental advancements in physics; particularly, adjacent matter-wave interferometers can use entanglement features to test physics beyond the standard model, test the equivalence principle, improve quantum sensors, and test the quantum nature of space-time in a laboratory. In particular, we study how white and flicker noise induces decoherence for a setup involving superconducting wires embedded in a chip. We show that to obtain a tiny spatial superposition of a nanometer separation, $\mathrm{\Delta }x\approx O\left({10}^{-9}\right)\mathrm{m}$ and to minimize decoherence, $\mathrm{\Gamma }\le O\left({\omega }_0/2\pi \right)$, where $\mathrm{\Gamma }$ is the dephasing rate and ${\omega }_0$ is the frequency of the oscillator, we will need current fluctuations to be $\delta I/I\le O\left({10}^{-8}\right)$, which is not impossible to obtain in superconducting wire arrangements. For such tiny fluctuations, we demonstrate that the Humpty-Dumpty problem in a matter-wave interferometer arising from a mismatch in position and momentum does not cause a loss in contrast.

Close

PrevNext

View figure in article

• Cold atoms & matter waves
• Quantum coherence & coherence measures
• Quantum harmonic oscillator
• Quantum measurements
• Quantum metrology
• Quantum parameter estimation
• Qubits