RAISE: TAQS: Two-Photon Quantum Photonic Logic Gates Enabled by Photonic Bound States

量子信息科学利用量子力学现象，如叠加和纠缠，以改善经典通信，计算，信息处理和精密测量。量子技术有望在加强国家安全和支持进一步科学发现方面发挥决定性作用。在量子信息处理中，单量子比特（qubit）操作不足以解锁由一组量子比特赋予的所有计算能力。因此，有必要并且事实上足以将诸如受控相位门之类的双量子位门添加到有限的单量子位门集合中，以实现在经典计算机上不再能够有效模拟的功能。在光量子计算中，光子量子比特由于其低噪声、长相干时间、光速传输和易于使用标准光学组件在单量子比特水平上操作而被用作信息载体。到目前为止，只有基于线性光学和光子探测器的概率双量子比特光子逻辑门已经被证明。然而，该实施方式与大量的资源开销相关联，并且需要严格的技术要求，这些技术要求在今天仍然具有挑战性。该项目通过开发确定性控制相位门来解决基本挑战，以实现量子计算的全部潜力。教育和推广活动将培养下一代量子科学家和工程师，以加快量子信息科学和应用的步伐。 技术摘要：这项工作的目标是开发一种新的技术方法来控制相位门的两个光子量子比特使用一种全新的方法的基础上产生的光子二聚体状态，手性纳米光子波导，和一个单一的偶极子发射器。在纳米光子波导中的横向方向上的紧密光学限制允许将偶极发射器放置在手性点处并且实现光子与发射器之间的强耦合，使得散射光子有效地耦合到前向传播模式而不是后向传播模式。相关光子形成光子二聚体，光子二聚体是光子的束缚态，并产生非平凡的透射π相移。控制相位门的验证将实现使用一种新的实验设计的基础上的集成波导的方法与数分辨光子探测器耦合。光子二聚体状态和相应的180度相移的演示与状态与两个光子与偶极子发射器相互作用将是一个重要的一步，在展示光子量子计算的潜力。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Quantum information science exploits quantum mechanical phenomena such as superposition and entanglement to improve classical communication, computation, information processing, and precision measurement. Quantum technology is expected to play a decisive role in enhancing national security and bolstering further scientific discovery. In quantum information processing, single-quantum bit (qubit) operations are not sufficient to unlock all the computational power that is endowed by a collection of qubits. Hence it is necessary and in fact sufficient to add a two-qubit gate such as a controlled-phase gate to a finite set of single-qubit gates to achieve what no longer can be efficiently simulated on a classical computer. In optical quantum computation, photonic qubits are used as information carriers due to their low-noise, long coherence times, light-speed transmission and ease of manipulation at the single-qubit level using standard optical components. To date, only probabilistic two-qubit photonic logic gates based on linear optics and photon detectors have been demonstrated. The implementation, however, is associated with substantial resource overhead and demands stringent technological requirements which are still challenging today. This project addresses the fundamental challenges by developing a deterministic controlled-phase gate to realize the full potential of quantum computation. The educational and outreach activities will train the next-generation quantum scientists and engineers to accelerate the pace of quantum information science and applications. Technical Abstract:The goal of this work is to develop a new technological approach to a controlled-phase gate for two photonic qubits using an entirely novel approach based on the generation of photonic dimer states, a chiral nano-photonic waveguide, and a single dipole emitter. The tight optical confinement in the transverse direction in the nanophotonic waveguide allows one to place the dipole emitter at the chiral point and achieve strong coupling between the photon and the emitter such that the scattered photons couple efficiently to the forward but not the backward-propagating mode. The correlated photons form the photonic dimers, which are the bound states of photons and give rise to a non-trivial transmission pi phase shift. The validation of the controlled-phase gate will be achieved using a novel experimental design based on an integrated waveguide approach coupled with number-resolved photon detectors. The demonstration of the photonic dimer state and the corresponding 180-degree phase shift associated with the state with both photons interacting with the dipole emitter will be a major step forward in demonstrating the potential of photonic quantum computing.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.