Searcharxiv⌕ Search

arXiv subjects

T. Yu. Golubeva

Publications and source records attributed to T. Yu. Golubeva.

At least 19 recordsLinked to original sources
arXiv2026

Growth of Schrödinger cats in particle-number measurement schemes

In this work, we investigate the generation of squeezed Schrödinger cat states in schemes based on photon-number-resolving measurements on multimode Gaussian states. We derive analytical expressions for the states generated in two- and three-mode schemes, as well as formulas for their fidelity with squeezed Schrödinger cat states. We analyze how the amplitude of the generated states scales with the number of detected particles. Furthermore, we derive an upper bound on the achievable generation fidelity and identify the conditions under which multimode schemes can enhance the quality of the generated states.

quant-ph↗
arXiv2025

Bosonic quantum error correction using squeezed Fock states

In the paper, we develop a bosonic quantum error correction code based on squeezed Fock states. We compare our proposed code with one based on squeezed Schrodinger's cat states using the Knill-Laflamme cost function and the Petz map fidelity. We demonstrate that squeezed Fock states are competitive in protecting information in a channel with particle loss and dephasing.

quant-ph↗
arXiv2024

Parallel two-qubit entangling gates via a quantum nondemolition interaction controlled by rotation

The paper presents an analysis of entangling and nonlocal operations in a quantum nondemolition (QND) interaction between multimode light with orbital angular momentum and an atomic ensemble. A protocol consists of two QND operations with rotations of quadratures of atomic spin coherence and light between them. This protocol provides a wide range of two-qubit operations, while the multimode nature of the chosen degrees of freedom allows the implementation of parallel operations over multiple two-qubit systems. We have used the formalism of equivalence classes and local invariants to evaluate the properties of two-qubit transformations. It is shown that, when selecting suitable values of the governing parameters, such as the duration of each of the two QND interactions and the rotation angles of the qubits, the protocol allows to realize a deterministic nonlocal $SWAP$ operation and entangling $\sqrt{SWAP}$ operation with probability 1/3.

quant-ph↗
arXiv2024

Comparison of Controlled-Z operation and beam-splitter transformation for generation of squeezed Fock states by measurement

The generation of squeezed Fock states by the one or more photon subtraction from a two-mode entangled Gaussian state using a beam splitter and a controlled-Z operation is addressed. From two different perspectives, we analyzed two entanglement transformations in the protocol. We evaluated the energy costs and resource requirements of the analyzed schemes. Furthermore, we studied the impact of experimental imperfections on the non-Gaussian states generated by measuring the number of particles. We explored the effects of photon loss and imperfect detectors on the squeezed Fock state generation protocol.

quant-ph↗
arXiv2024

Estimation of the set of states obtained in particle number measurement schemes

The paper investigated a set of non-Gaussian states generated by measuring the number of particles in one of the modes of a two-mode entangled Gaussian state. It was demonstrated that all generated states depend on two types of parameters: some parameters are responsible for Gaussian characteristics, while other parameters are responsible for non-Gaussian characteristics. Among all generated states, we identified those optimally generated in terms of the generation probability and the magnitude of non-Gaussianity.

quant-ph↗
arXiv2024

Generation of squeezed Fock states by measurement

The generation of squeezed Fock states by the one or more photon subtraction from a two-mode entangled Gaussian (TMEG) state is theoretically addressed. We showed that an arbitrary order Fock state can be generated this way and we obtained a condition that should be imposed on the parameters of the TMEG state to guaranty such a generation. We called the regime, in which this condition is satisfied, universal solution regime. We showed that, for first squeezed Fock state, the above condition is redundant such that the generation of the first squeezed Fock state is still possible by a one photon subtraction from an arbitrary TMEG state. At the same time, the maximum generation probability of the first squeezed Fock state generation corresponds to the universal solution regime. We applied the above results to the description of generation of the squeezed Fock states using a beam splitter and a Controlled-Z operation. We have estimated the parameters of such setups and input squeezed states, which are necessary to obtain squeezed Fock states with the maximum probability.

quant-ph↗
arXiv2023

Error Correction Using Squeezed Fock States

The paper addresses the construction an error correction code for quantum calculations based on squeezed Fock states. It is shown that the use of squeezed Fock states makes it possible to satisfy the Knill-Laflamme (KL) criteria for bosonic error correction codes. It is shown that the first squeezed Fock state corrects both photon loss and dephasing errors better than higher-order states. A comparison of the proposed protocol with an error correction protocol based on the squeezed Schrodinger's cat states is carried out on the basis of the KL cost function. It is shown that the squeezed first Fock state better protects a channel with photon loss and dephasing.

quant-ph↗
arXiv2023

Parallel multi-two-qubit SWAP gate via QND interaction of OAM light and atomic ensemble

Nowadays quantum SWAP gate has become an integral part of quantum computing, so investigation of methods of its realization seems to be an important practical problem for various quantum-optical and information applications. In the present paper we propose a scheme for performing a SWAP logic operation in discrete variables in the framework of quantum non-demolition interaction between an atomic ensemble and a multimode light with orbital angular momentum. We discuss in detail the procedure for revealing two-qubit closed subsystems on a set of atomic and field states for different values of the driving field orbital momentum. We also demonstrate the possibility of implementing a parallel multi-two-qubit quantum SWAP gate.

quant-ph↗
arXiv2023

Generation of Non-Gaussian States in the Squeezed State Entanglement Scheme

The paper considers the possibility of generating different non-Gaussian states using the entangled state photon measurement scheme. In the paper, we have proposed a way to explicitly find the wave function and the Wigner function of the output state of this scheme. Moreover, the solutions found are not restricted to any particular case, but have maximum generality (depend on the number of measured photons and on all parameters of the scheme). Such a notation allowed us to carry out a complete analysis of the output states, depending on the scheme parameters. Using explicit expressions, we have analyzed the magnitude of non-Gaussianity of the output states, and we have revealed which particular states can be obtained in the proposed scheme. We have considered in detail a particular case of measurement (single photon measurement) and have shown that using explicit expressions for the output state wave function one can find scheme parameters to obtain states suitable for quantum error correction codes with a large fidelity value and high probability. The Schrodinger cat state with amplitude $α=2$ can be obtained with fidelity $F \approx 0.88$ and probability 18 percent, and the squeezed Schrodinger cat state ($α=0.5$, $R=1$) with fidelity $F \approx 0.98$ and probability 22 percent.

quant-ph↗
arXiv2023

Heralded gate search with genetic algorithms for quantum computation

In this paper we present genetic algorithms based search technique for the linear optics schemes, performing two-qubit quantum gates. We successfully applied this technique for finding heralded two-qubit gates and obtained the new schemes with performance parameters equal to the best currently known. The new simple metrics is introduced which enables comparison of schemes with different heralding mechanisms. The scheme performance degradation is discussed for the cases when detectors in the heralding part of the scheme are not photon-number-resolving. We propose a procedure for overcoming this drawback which allows us to restore the reliable heralding signal even with not-photon-number-resolving detectors.

quant-ph↗
arXiv2022

Error of an arbitrary single-mode Gaussian transformation on a weighted cluster state using a cubic phase gate

In this paper, we propose two strategies for decreasing the error of arbitrary single-mode Gaussian transformations implemented using one-way quantum computation on a four-node linear cluster state. We show that it is possible to minimize the error of the arbitrary single-mode Gaussian transformation by a proper choice of the weight coefficients of the cluster state. We modify the computation scheme by adding a non-Gaussian state obtained using a cubic phase gate as one of the nodes of the cluster. This further decreases the computation error. We evaluate the efficiencies of the proposed optimization schemes comparing the probabilities of the error correction of the quantum computations with and without optimizations. We have shown that for some transformations, the error probability can be reduced by up to 900 times.

quant-ph↗
arXiv2022

Teleportation protocols with non-Gaussian operations: conditional photon subtraction versus cubic phase gate

In our work, we compare three teleportation protocols: the original protocol, the photon subtraction protocol, and the protocol with a cubic phase gate. We evaluate the fidelity of each protocol using the example of teleportation of the squeezed state and the Schrodinger's cat state. We show that, under equal conditions, the teleportation scheme with a cubic phase gate achieves significantly higher fidelity than the other protocols considered.

quant-ph↗
arXiv2021

Broadband chip-based source of a quantum noise with electrically-controllable beam splitter

For the first time, the theory and practical realization of a broadband quantum noise generator based on original integrated optical beam splitter in the form of a Mach-Zehnder interferometer is demonstrated. The beam splitter with a double output, made on a lithium niobate substrate, provided accurate electro-optical balancing of the homodyne quantum noise detection circuit. According to our knowledge, the experimentally obtained excess of quantum noise over classical noise by 12 dB in the frequency band over 4 GHz, which is the best parameters of quantum noise generators known from the literature.

quant-ph↗
arXiv2021

Teleportation with a cubic phase gate

We propose a modified quantum teleportation scheme to increase the teleportation accuracy by applying a cubic phase gate to the displaced squeezed state. We have described the proposed scheme in Heisenberg's language, evaluating it from the point of view of adding an error in teleportation, and have shown that it allows achieving less error than the original scheme. Repeating the description in the language of wave functions, we have found the range of the displacement values, at which our conclusions will be valid. Using the example of teleportation of the vacuum state, we have shown that the scheme allows one to achieve high fidelity values.

quant-ph↗
arXiv2021

High-fidelity quantum gates for OAM qudits on quantum memory

The application of high-dimensional quantum systems (qudits) in quantum computing and communications seems to be a promising avenue due to the possibility of increasing the amount of information encoded in one physical carrier. In this work, we propose a method for implementing single-qudit gates for qudits based on light modes with orbital angular momentum. Method for logical qudits encoding, which ensures the quasi-cyclicity of operations, is introduced. Based on the protocol for converting the orbital angular momentum of light in the Raman quantum memory scheme [Vashukevich E.A. et. al. PRA, 101, 033830 (2020)], we show that the considered gates provide an extremely high level of fidelity of single-qudit transformations. We also compare quantum gates' properties for systems of different dimensions and find the optimal conditions for carrying out transformations in the protocol under consideration.

quant-ph↗
arXiv2020

Two-photon bunching inside a quantum memory cell

We demonstrate the effect of interference, similar to the Hong-Ou-Mandel effect, for two single-photon pulses by writing them sequentially inside a quantum memory cell in a tripod configuration.

quant-ph↗
arXiv2020

Finding the optimal cluster state configuration. Minimization of one-way quantum computation errors

In this paper, we estimate the errors of Gaussian transformations implemented using one-way quantum computations on cluster states of various configurations. From all possible cluster state configurations, we choose those that give the smallest computation error. Furthermore, we evaluate errors in hybrid computational schemes, in which Gaussian operations are performed using one-way computations with additional linear transformations. As a result, we find the optimal strategy for the implementation of universal Gaussian computations with minimal errors.

quant-ph↗