Russian scientists at the Physics Institute of the Russian Academy of Sciences have presented a quantum computer with 70 qubits based on an ion chain, and the accuracy of single-qubit operations in it reached 99.92%.
The Russian news agency TASS reported that scientists from the Institute of Physics of the Russian Academy of Sciences presented a quantum computer with 70 qubits based on an ion chain, with a single-qubit accuracy of 99.92% and a two-qubit accuracy of 95.4% .
"We have demonstrated that we have 35 ytterbium ions, and we control four states for each ion, which makes the system function as a 70-qubit quantum computer," said Ilya Zalefako, senior research scientist at the institute.
The developers explained that the computer's operating principle relies on the collective oscillations of the ion chain : when any ion is affected, the chain begins to oscillate, and these shared oscillation patterns enable all particles to interact and perform quantum operations. To execute two-qubit operations, special laser pulses are applied to a specific pair of ions.
This development differs from classical ion quantum computers in its chosen encoding structure. In systems with a single ion chain, the number of qubits typically does not exceed 35, because chain growth increases the complexity of controlling the oscillation spectrum and the entanglement of quantum states. The physics institute, however, increased the number of qubits by encoding information more densely within the particles using four-level quantum systems, equivalent to two qubits in a single ion.
To allow individual control of each ion, two laser beams moving rapidly along the ion chain are used to direct them to a specific ion, enabling independent control of the quantum state of each particle and monitoring of four states for each ion.
The qubit interconnection is implemented according to a "triple star" scheme , allowing quantum operations to be performed between different qubits without being restricted to nearest neighbors. The system ran several quantum algorithms, including the Grover database search algorithm , the Bernstein-Fazerani algorithm, and GHZ state preparation .
The developers indicated that the system is intended for practical testing and improving quantitative algorithms, and is currently being used to run calculations via a cloud platform .
