Ye Yufeng, Kline Jeremy B, Yen Alec, Cunningham Gregory, Tan Max, Zang Alicia, Gingras Michael, Niedzielski Bethany M, Stickler Hannah, Serniak Kyle, Schwartz Mollie E, O'Brien Kevin P
Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
Nat Commun. 2025 Apr 30;16(1):3799. doi: 10.1038/s41467-025-59152-z.
Light-matter interaction between an atom and an electromagnetic resonator is ubiquitous in quantum technologies. Although linear light-matter coupling can reach the ultrastrong regime g/ω > 10, nonlinear light-matter coupling is typically perturbative and limited to χ/ω < 10. Nonlinear coupling has the advantage of commuting with the atomic and photonic Hamiltonian, allowing for fundamental operations such as quantum-non-demolition measurement. Here, we use a superconducting circuit to demonstrate the experimental realization of near-ultrastrong χ/ω = (4.852 ± 0.006) × 10. We also show signatures of light-light nonlinear coupling ( ) and χ/2π = 580.3 ± 0.4 MHz matter-matter nonlinear coupling ( ), representing the largest reported ZZ interaction between two coherent qubits. Such advances in the nonlinear coupling strength of light, matter modes enable new physical regimes and could lead to orders of magnitude faster qubit readout and gates.
原子与电磁谐振器之间的光与物质相互作用在量子技术中无处不在。尽管线性光与物质耦合可以达到超强 regime g/ω > 10，但非线性光与物质耦合通常是微扰性的，并且限于 χ/ω < 10。非线性耦合具有与原子和光子哈密顿量对易的优点，允许进行诸如量子非破坏测量等基本操作。在这里，我们使用超导电路来演示近超强 χ/ω = (4.852 ± 0.006) × 10 的实验实现。我们还展示了光-光非线性耦合（ ）和 χ/2π = 580.3 ± 0.4 MHz 物质-物质非线性耦合（ ）的特征，这代表了两个相干量子比特之间报道的最大 ZZ 相互作用。光、物质模式非线性耦合强度的这种进展开启了新的物理领域，并可能导致量子比特读出和门操作速度提高几个数量级。
