MicroCloud Hologram Inc. announced the development of a revolutionary technology: state-based imaginary-time evolution quantum simulation. This innovative breakthrough marks the entry of quantum simulation technology into an entirely new era. It not only solves the long-standing problem of non-unitary evolution simulation that has plagued quantum computing, but also provides an efficient and scalable solution for quantum computers to compute the ground states of complex quantum systems in practical applications.
The core of the state-based imaginary-time evolution quantum simulation technology lies in utilizing a carefully prepared set of quantum states, and achieving non-unitary imaginary-time evolution simulation solely through controlled swap gates and measurement operations, without relying on any intermediate classical computation or complex quantum state tomography processes. Measurement operations constitute another key component of this protocol. In traditional quantum computing, measurement often leads to state collapse, but HOLO's method cleverly transforms measurement into a selection mechanism during the evolution process.
After each measurement, the system selectively retains those branches corresponding to lower energy components based on the measurement outcomes. This post-selection strategy ensures convergence of the evolution toward the ground state without requiring a classical feedback loop. Importantly, the entire process is fully quantized: all decisions and adjustments are completed within the quantum circuit, avoiding bottlenecks at the quantum-classical interface.
This stands in stark contrast to previous methods?for example, Quantum Phase Estimation requires a large number of auxiliary qubits and classical post-processing, whereas HOLO's technology only needs a small number of auxiliary states and standard measurement circuits. In simulation experiments, HOLO demonstrated that for small quantum systems, this method can achieve high-fidelity ground state approximations within a limited number of imaginary time steps, with an error rate below 10^{-3}. The advantage of HOLO's method lies in its noise robustness.
In real quantum hardware, noise is the primary obstacle, but since the protocol uses only shallow-depth circuits (circuit depth scales linearly with system size) and a small number of measurements, the error rate can be effectively controlled. Furthermore, there is no need for state tomography?an operation that is resource-intensive and typically requires an exponential number of measurements to reconstruct the quantum state?thereby further reducing overhead. In comparison, traditional imaginary-time variational methods (such as VITE) rely on classical optimizers and may get trapped in local minima, whereas HOLO's technology avoids this issue through intrinsic quantum mechanisms. HOLO-developed state-based imaginary-time evolution quantum simulation technology marks a substantial breakthrough in quantum computing's ability to handle non-unitary dynamical problems. With controlled swap gates and measurements as its core, it achieves fully endogenous imaginary-time evolution relying solely on quantum resources, avoiding the heavy dependence on classical optimization, state tomography, or deep circuits that characterizes traditional methods.
This innovation not only theoretically expands the boundaries of quantum simulation, but also demonstrates, in engineering practice, a high degree of friendliness toward existing NISQ devices, providing a noise-robust and scalable new path for ground state solving. Its emergence allows people to see that even before fault-tolerant quantum computing fully arrives, quantum machines are already capable of approaching many long-intractable quantum many-body ground state problems in entirely new ways.
