Propagation of microwave photons along a synthetic dimension
Propagation of microwave photons along a synthetic dimension
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DOI：
10.1103/physreva.101.053807
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发表时间：
2020-05-04
影响因子：
2.9
通讯作者：
Safavi-Naeni, Amir H.
中科院分区：
文献类型：
--
作者：
Lee, Nathan R. A.;Pechal, Marek;Safavi-Naeni, Amir H.
电磁谐振器的均匀间隔模式通过适当的时间调制相互耦合，从而产生类似于粒子在晶格的不同位置之间跳跃的动力学。这种用频率空间中的“合成”维度代替晶格的真实空间维度大大降低了模拟量子模拟器的硬件复杂性。因此，可以用很少的物理控制线来完成高度多模结构的复杂控制和读出。我们通过在谐振器自由光谱范围附近的频率调制系统参数并观察时域中光子波包的传播，用超导传输线谐振器中的微波光子证明了这一概念。线性传播动力学相当于紧束缚模型，我们通过测量频率站点之间的散射参数来探测该模型。我们提取合成晶格的近似紧束缚色散关系，并用明确定义的准速度和群速度初始化光子波包。作为该平台在模拟物理系统中的示例应用，我们演示了与处于周期性势且受到恒定外场影响的粒子相关的布洛赫振荡。尽管光子电荷为零，但模拟场强烈影响光子动力学。我们对合成频率维度上的光子动力学的观察立即推广到拓扑光子学和单光子功率水平，并扩展了量子模拟可寻址的物理系统的范围。
The evenly spaced modes of an electromagnetic resonator are coupled to each other by appropriate time modulation, leading to dynamics analogous to those of particles hopping between different sites of a lattice. This substitution of a real spatial dimension of a lattice with a "synthetic" dimension in frequency space greatly reduces the hardware complexity of an analog quantum simulator. Complex control and readout of a highly multimoded structure can thus be accomplished with very few physical control lines. We demonstrate this concept with microwave photons in a superconducting transmission line resonator by modulating the system parameters at frequencies near the resonator's free spectral range and observing propagation of photon wave packets in time domain. The linear propagation dynamics are equivalent to a tight-binding model, which we probe by measuring scattering parameters between frequency sites. We extract an approximate tight-binding dispersion relation for the synthetic lattice and initialize photon wave packets with well-defined quasimomenta and group velocities. As an example application of this platform in simulating a physical system, we demonstrate Bloch oscillations associated with a particle in a periodic potential and subject to a constant external field. The simulated field strongly affects the photon dynamics despite photons having zero charge. Our observation of photon dynamics along a synthetic frequency dimension generalizes immediately to topological photonics and single-photon power levels, and expands the range of physical systems addressable by quantum simulation.