Oscar Adamuz-Hinojosa, Jonathan Prados-Garzon, Sara Vaquero-Gil, Juan M. Lopez-Soler • Published: 2026-03-30
Quantum networks (QNs) enable the transfer of qubits between distant nodes using quantum teleportation, which reproduces a qubit state at a remote location by consuming a shared Bell pair. After teleportation, qubits are stored in quantum memories, where decoherence progressively degrades their quantum states. This degradation is quantified by the fidelity, defined as the overlap between the store...
Örs Legeza, Andor Menczer, Miklós Antal Werner, Sotiris S. Xantheas, Frank Neese, Martin Ganahl, Cole Brower, Samuel Rodriguez Bernabeu, Jeff Hammond, John Gunnels • Published: 2026-03-30
In light of major developments over the past decades in both quantum computing and simulations on classical hardware, it is a serious challenge to identify a real-world problem where quantum advantage is expected to appear. In quantum chemistry, electronic structure calculations of strongly correlated, i.e. multi-reference problems, are often argued to fall into such category because of their intr...
Madelyn Cain, Qian Xu, Robbie King, Lewis R. B. Picard, Harry Levine, Manuel Endres, John Preskill, Hsin-Yuan Huang, Dolev Bluvstein • Published: 2026-03-30
Quantum computers have the potential to perform computational tasks beyond the reach of classical machines. A prominent example is Shor's algorithm for integer factorization and discrete logarithms, which is of both fundamental importance and practical relevance to cryptography. However, due to the high overhead of quantum error correction, optimized resource estimates for cryptographically releva...
Ziang Wang, Shuyuan Guan, Feng Wu, Xiaohang Zhang, Qiong Li, Jianxin Chen, Xin Wan, Tian Xia, Hui-Hai Zhao • Published: 2026-03-30
An accurate and efficient numerical electromagnetic model for superconducting qubits is essential for characterizing and minimizing design-dependent dielectric losses. The energy participation ratio (EPR) is the commonly adopted metric used to evaluate these losses, but its calculation presents a severe multiscale computational challenge. Conventional finite element method (FEM) requires 3D volume...
Marek Kuchař, Michal Macek • Published: 2026-03-30
We propose concrete protocols to realize quantum criticality due to excited-state quantum phase transitions (ESQPTs) experimentally in presumably the simplest and most resilient system involving a single trapped ion oscillating in a radio-frequency Paul trap. We identify a specific class of excited states of the Extended Rabi Model (ERM) Hamiltonian, which occur between two critical ESQPT energies...
Teodor Iličin, Rok Žitko • Published: 2025-12-28
We investigate the superconducting Anderson impurity model for interacting quantum dot Josephson junctions with spin-orbit coupling and a term accounting for tunnelling through higher-energy orbitals. These elements establish the conditions required for spin polarization in the absence of external magnetic field at finite superconducting phase bias. This Hamiltonian has been previously used to mod...
Jadwiga Wilkens, Milena Guevara-Bertsch, Marwa Marso, Mederika Zangerl, Albert Frisch, Florian Girtler, Juris Ulmanis, Ingo Roth, Richard Kueng • Published: 2026-03-30
We experimentally demonstrate local robust shadows on a trapped-ion device, a protocol developed to counteract measurement errors. We alternate between a calibration stage and the shadow estimation stage and also introduce Pauli-X-twirling before measurements in both stages to symmetrize error rates. We then demonstrate the protocol on a trapped-ion quantum computer with artificially shortened mea...
Masatoshi Ishii, Hammam Qassim, Tomochika Kurita, Joseph Emerson, Kazunori Maruyama, Hirotaka Oshima, Shintaro Sato • Published: 2025-03-07
In near-term quantum computations that do not employ error correction, noise can proliferate rapidly, corrupting the quantum state and making results unreliable. These errors originate from both decoherence and control imprecision. The latter can manifest as coherent noise that is especially detrimental. Here, we study the impact of coherent errors and their mitigation under standard error-reducti...