The use of non-uniform filters with a controlled spatial absorption profile has improved the spatiotemporal profile of amplified signal and idler pulses in a two-stage parametric amplification scheme for femtosecond pulses. The measured dependence of the signal wave emission spectrum on the transverse coordinate reveals high homogeneity with suppression of the central part of the seed pulse beam, while the 2+1-dimensional numerical simulation of the parametric amplification process for femtosecond pulses predicts a corresponding increase in the homogeneity of the temporal profile of the signal and idler pulses and a decrease in their duration. The efficiency of the corresponding parametric conversion of submillijoule pulses reaches 50
Hybrid quantum systems that combine discrete-variable (DV) and continuous-variable (CV) architectures represent a promising direction in quantum information science. However, transferring concepts, information, and states between such fundamentally different platforms entails both practical and theoretical challenges. The formalisms of these two "universes" differ significantly, and many notions, although sharing the same names, possess distinct properties and physical interpretations. In this work, we construct a sector wise bridge between DV spin systems and restricted CV bosonic systems by means of the tomographic probability representation of quantum states complemented by the Jordan-Schwinger and Holstein-Primakoff maps. While both maps are well known at the operator level, their action on the classical counterparts of quantum states, namely tomograms and other probability representations, has not been addressed in the literature. To the best of our knowledge, this work provides the first explicit demonstration of how the Jordan-Schwinger and Holstein-Primakoff maps act on tomographic probability distributions and Wigner functions, thereby establishing direct sector wise correspondences between the classical measurement statistical descriptions of DV systems and the corresponding restricted CV bosonic representations. Our tomographic mapping enables a direct transfer of measurement data between different quantum architectures by acting as an intrinsic data compression kernel that selects the Hilbert space sector relevant to the target representation. It allows one to obtain the tomogram of a target sector directly from experimentally acquired data in another representation, without reconstructing the density matrix. This provides a unified framework for transferring and comparing quantum information across heterogeneous quantum hardware platforms within the corresponding restricted sectors, facilitating hybrid protocols, device benchmarking, and the validation of error correction schemes that rely on mappings between finite-dimensional systems and sector restricted bosonic representations.
Increasing the utility of currently available Noisy Intermediate-Scale Quantum (NISQ) devices requires developing efficient methods to mitigate hardware errors, taking into account the constraints of these devices such as medium number of qubits and limited connectivity between them. In this work we propose a novel Cyclic Layout Permutations based Zero Noise Extrapolation (CLP-ZNE) protocol for such a task. The method leverages the inherent non-uniformity of gate errors in NISQ hardware and exploits symmetries of quantum circuits with one-dimensional connectivity to extrapolate the expectation value, averaged over cyclic circuit layout permutations, to the level of zero noise. In contrast to the previous layout permutation based approaches, for $n$ qubit circuit CLP-ZNE requires measurements of only $O(n)$ different circuit layouts to reconstruct the noiseless expected value. When benchmarked against noise channels modeling the IBM Torino quantum computer, the method reduces a typical expectation value error by an order of magnitude, depending on the protocol specifications. By employing a noise model derived from real hardware specifications, including both depolarizing and $T_1/T_2$ relaxation processes, these results give evidence for the applicability of CLP-ZNE to present-day NISQ processors.
Lanthanides are nowadays extensively used to investigate the properties of strongly correlated matter. Nevertheless, exploiting the Zeeman manifold of a lanthanide atom ground state is challenging due to the unavoidable presence of depolarization collisions. Here we demonstrate that in the case of the thulium atom, it is possible to suppress this depolarization by a factor of 1000 with a carefully tuned magnetic field thus opening the way for the efficient use of the Zeeman manifold in quantum simulations.
Quantum error correction (QEC) is essential for achieving fault-tolerant quantum computing. While superconducting qubits are among the most promising candidates for scalable QEC, their limited nearest-neighbor connectivity presents significant challenges for implementing a wide range of error correction codes. In this work, we experimentally demonstrate a quantum error detection scheme that employs a dynamically reassigned ancillary qubit on a chain of three linearly connected transmon qubits. We show that this scheme appears capable of achieving performance comparable to conventional static-ancilla circuits. Additionally, the approach facilitates efficient quantum state preparation, which we demonstrate with tomography of arbitrary logical states. Our results provide experimental evidence for a flexible strategy that could be used for implementing QEC codes under connectivity constraints and highlight a possible path toward scalable quantum architectures.
