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Alexander Yeremeyev

Publications and source records attributed to Alexander Yeremeyev.

2 recordsLinked to original sources

Transport of magnetically sensitive atoms in a magnetic environment

Among interesting applications of cold atoms, quantum simulations attract a lot of attention. In this context, rare-earth ultracold atoms are particularly appealing for such simulators due to their numerous Fano-Feshbach resonances and magnetic dipole moments in the ground state. Creating a quantum gas microscope requires a large optical access that may be achieved using transport of atoms between separate vacuum volumes. We demonstrate that in case of the transport of magnetic atoms the magnetic field can be directly measured and adjusted to reduce additional losses after the transport therefore increasing the efficiency of subsequent evaporation cooling. This approach allows to transfer over 85% of the atoms from the main chamber to the scientific chamber, located 38 cm away with moderate laser power of 26 W without atomic polarization decay.

cond-mat.quant-gas

Variational preparation of entangled states in a system of transmon qubits

The conventional method for generating entangled states in qubit systems relies on applying precise two-qubit entangling gates alongside single-qubit rotations. However, achieving high-fidelity entanglement demands high accuracy in two-qubit operations, requiring complex calibration protocols. In this work, we use a minimally calibrated two-qubit iSwap-like gate, tuned via straightforward parameter optimization (flux pulse amplitude and duration), to prepare Bell states and GHZ states experimentally in systems of two and three transmon qubits. By integrating this gate into a variational quantum algorithm (VQA), we bypass the need for intricate calibration while maintaining high fidelity. Our proposed methodology employs variational quantum algorithms (VQAs) to create the target quantum state through imperfect multiqubit operations. Furthermore, we experimentally demonstrate a violation of the Clauser-Horne-Shimony-Holt (CHSH) inequality for Bell states, confirming their high fidelity of preparation.

quant-ph