arXiv subjects

Ilya Semerikov

Publications and source records attributed to Ilya Semerikov.

5 recordsLinked to original sources

arXiv2026

Analysis of the action of conventional trapped-ion entangling gates in qudit space

Qudits, or multi-level quantum information carriers, present a promising path for scaling quantum computers. However, their use introduces increased complexity in quantum logic, necessitating careful control of relative phases between different qudit levels. In trapped-ion systems, entangling operations accumulate phases on specific levels that are no longer global, unlike in qubit architectures. Furthermore, the structure of multi-level gates becomes increasingly intricate with higher-dimensional Hilbert spaces. This work explores the theory of these additional local and nonlocal phases, accumulated in Mølmer--Sørensen and Light-shift gates. We propose methods to actively compensate for these phases, enhance gate robustness against parameter fluctuations, and simplify native gates for more efficient circuit decomposition. Our results pave the way toward the practical and scalable implementation of qudit-based quantum processors.

quant-ph↗

arXiv2025

In-situ Doppler-free spectroscopy with pulsed optical fields

We propose a novel pulsed optical field method that alternately switches the pump beam in conventional saturation absorption to time-division multiplex the same probe beam into both probe and reference beams, followed by digital differential processing to achieve deterministic zero-background Doppler-free spectroscopy. This method effectively mitigates Doppler broadening and common-mode optical noise by addressing disturbances such as non-uniform background absorption and environmental noise, thereby offering enhanced accuracy and robustness. Using this technique, we measured the absolute frequency of Yb$^{+}$ isotopes in the $6s^2\ ^{1}S_0\to 6s6p ^{1}P_1$ transition. By employing an error signal derived from the first-derivative demodulated spectrum of $^{174}\mathrm{Yb}^{+}$, we achieved efficient stabilization of a 369.5 nm ultraviolet diode laser, demonstrating a frequency stability of $3 \times 10^{-11}$ over a 1500-second averaging period and a locking point uncertainty of 850 kHz sustained over 10 days. Furthermore, we report the first in-situ observation of Doppler-free Zeeman sub-level spectra, highlighting the precision of this method and its potential application in measuring magnetic field gradients.

physics.optics↗

arXiv2024

Optimized surface ion trap design for tight confinement and separation of ion chains

Qubit systems based on trapped ultracold ions win one of the leading positions in the quantum computing field, demonstrating quantum algorithms with the highest complexity to date. Surface Paul traps for ion confinement open the opportunity to scale quantum processors to hundreds of qubits and enable high-connectivity manipulations on ions. To fabricate such a system with certain characteristics, the special design of a surface electrode structure is required. The depth of the trapping potential, the stability parameter, the secular frequency and the distance between an ion and the trap surface should be optimized for better performance. Here we present the optimized design of a relatively simple surface trap that allows several important high-fidelity primitives: tight ion confinement, laser cooling, and wide optical access. The suggested trap design also allows to perform an important basic operation, namely, splitting an ion chain into two parts.

quant-ph↗

arXiv2021

Coherent effects contribution to a fast gate fidelity in ion quantum computer

Trapped ions are one of the most promising platforms for quantum computing due to the longest qubit coherence times and the highest gate fidelities. However, scaling the number of ions (qubits) in a linear Coulomb crystal is the key difficulty on the way to multi-qubit systems. One of the promising pathways to scale the number of qubits is to implement the pulsed non-adiabatic gates based on the sequence of State Dependent Kicks (SDKs). We have analytically and numerically studied the influence of coherent effects in the SDK sequence and, correspondingly, have deduced the influence of the individual SDK error on the net gate fidelity. We have shown that the coherence effects significantly impact the fidelity of non-adiabatic gates and must be taken into the account. As practical examples, we have developed a numerical model for full simulation of coherence effects using a linear ion microtrap array and a 2D microtrap array. We have also studied the dependency of the gate fidelity on the laser power fluctuations.

physics.atom-ph↗

arXiv2020

Compact transportable 171Yb+ single-ion optical fully automated clock with 4.9E-16 relative instability

The paper describes the results achieved in the development of the compact transportable fully automated optical clock based on a single 171Yb+ ion in a radiofrequency (RF) quadrupole trap. The resulted measurements demonstrated the 4.9E-16 output RF signal relative instability on 1000 s integration time with 298.1 kg weight, 0.921 volume, and 2.766 kW input power consumption of the device. A transformation of the ultrastable optical signal into the RF range was performed via the optical frequency comb with a supercontinuum fiber laser generator. The transformation was conducted without loss of initial stability and accuracy characteristics of the signal.

physics.ins-det↗