Measurement-Based Deterministic Imaginary Time Evolution.

We introduce a method to perform imaginary time evolution in a controllable quantum system using measurements and conditional unitary operations. By performing a sequence of weak measurements based on the desired Hamiltonian constructed by a Suzuki-Trotter decomposition, an evolution approximating imaginary time evolution can be realized. The randomness due to measurement is corrected using conditional unitary operations, making the evolution deterministic. Both the measurements required for the algorithm and the conditional unitary operations can be constructed efficiently. We show that the algorithm converges only below a specified energy threshold and the complexity is estimated for some specific problem instances.

Optical circuit compactification for ultracold atoms.

We develop a modular and compactified optical circuit for the generation of optical beams for cooling, imaging, and controlling ultracold atoms. One of the simplifications that is made in our circuit is to admix the repumping beams to each other optical beams in its dedicated single-mode fiber. We implement our design, characterize the output, and show that the optical power efficiency of the circuit is in the region of 97%, and after fiber coupling, the efficiencies are in the range of 62-85%. Given its compact design and controllable optical sources, this setup should be adaptable to a variety of quantum experiments based on ultracold gases.