A system for controlling a phase measurement in an atom interferometer comprising one or more lasers, a processor, and a memory. The one or more lasers are for providing interrogating beams. A first cloud of atoms and a second cloud of atoms traverse an interrogating region of the atom interferometer in substantially opposite directions. The interrogating beams interact substantially simultaneously with both atoms in the first cloud and atoms in the second cloud. The first cloud of atoms and the second cloud of atoms interact with each of the interrogating beams in a different order. The processor is configured to determine a phase adjustment offset of at least one interrogating beam based at least in part on one or more past interactions of one or more interrogating beams with either the first cloud of atoms or the second cloud of atoms.

Measurement-only topological quantum computation using both projective and interferometrical measurement of topological charge is described. Various issues that would arise when realizing it in fractional quantum Hall systems are discussed.

A method for filtering matter waves (MW) from a composite particle beam, comprising: obtaining the composite particle beam from a first particle path, the beam comprising a matter-wave-energy (an MWE) particle component and a matter wave (an MW) component, wherein the MW component does not correspond to the MWE particle component; directing the composite particle beam toward a unit having a distribution of a non-uniform spatial field; tilting the MWE particle component of the composite particle beam toward a second path away from the first path; generating an output beam of the MW component along the first path going through the non-uniform spatial field; and receiving the output beam of the MW component for processing in a subsequent step.

An optical source is configured to simultaneously generate a set of four time-correlated photons comprising a first pair of photons and a second pair of photons. An interferometer is configured to receive a photon from the first pair of photons and configured to receive another photon from the first pair of photons. A first and a second detector configured to generate an electrical signal in response to measurements of an output of the interferometer. A third detector is configured to generate an electrical signal in response to measurement of a photon from the second pair of photons. A fourth detector is configured to generate an electrical signal in response to measurement of another photon from the second pair of photons. A processor is configured to determine a coincidence of the generated electrical signals in response to measurements of the second pair of photons, thereby identifying the set of four time-correlated photons and heralding an interferometric measurement from the generated electrical signals of the first and second detectors.

During one or more active periods of time over which at least one of an amplitude, frequency, or phase of one or more optical wave(s) are modified, the optical wave(s) overlap with and interact with a gaseous cloud of IAMs and transfer portions of the among different distributions of momentum states. Control signals for controlling aspects of the optical wave(s) are determined based at least in part on (1) a constraint determined based at least in part on a set of optical wave parameters, and a set of quantum state parameters, where two or more of the quantum state parameters do not satisfy the constraint, and/or (2) a partial derivative of one or more quantum states associated with the IAMs, where the partial derivative is with respect to an optimization parameter determined based at least in part on the one or more optical waves or the estimation parameter.

A system for controlling a phase measurement in an atom interferometer comprising one or more lasers, a processor, and a memory. The one or more lasers are for providing interrogating beams. A first cloud of atoms and a second cloud of atoms traverse an interrogating region of the atom interferometer in substantially opposite directions. The interrogating beams interact substantially simultaneously with both atoms in the first cloud and atoms in the second cloud. The first cloud of atoms and the second cloud of atoms interact with each of the interrogating beams in a different order. The processor is configured to determine a phase adjustment offset of at least one interrogating beam based at least in part on one or more past interactions of one or more interrogating beams with either the first cloud of atoms or the second cloud of atoms.

A non-invasive measuring/diagnosis/treatment apparatus and method includes an MWE particle source for emitting particles, the particles comprises a first particle beam and a second particle beam with enclosed space at a partial vacuum and low humidity environment. A first beam splitter for making MW of a first particle beam and MWE of a second particle beam toward a first path, and making MW of the second particle beam and MWE of the first particle beam toward a second path. An MW filter having a distribution of a non-uniform spatial field located at the first path for tilting the MWE of the second particle beam and let the MW of the first particle beam transmit a sample located on the first path and a first detector for detecting a plurality of peaks or valleys of the first interference pattern.