#rabidrive

Rabi-Driven Qubit

Technological Breakthrough: Rabi-Driven Qubit Unlocks Next-Gen Quantum Computing Record Squeezing

E. Blumenthal, N. Gutman, I. Kaminer, and his colleagues at the Technion, Israel Institute of Technology, have found a new approach for creating high-level compressed states of light needed for bosonic quantum computing. A Rabi-driven qubit is crucial to this technology and actively managed. In specifically, a Rabi-driven qubit is used to finely control light's quantum properties in a system.

In this study, a transmon qubit is a two-level quantum system. In superconducting resonators, the controller coordinates interactions with harmonic oscillators, which represent light's vibrational modes. A 'Rabi drive' or 'radio wave' drive exposes the qubit to a well-controlled oscillating microwave field.

Rabi frequency-identified drive controls qubit state. This system may achieve an experimental Rabi frequency of MHz, according to sources. To avoid the transmon from populating undesirable higher excited states, the Rabi drive amplitude must be low enough in comparison to its anharmonicity to make it a two-level system.

Squeezed states are created by dispersively linking the Rabi-driven qubit to the harmonic oscillator or oscillators. Dispersive coupling implies that the qubit's state changes the resonator's frequency without exchanging photons. This interaction is measured via dispersive shift. Managing this connection between the harmonic modes and Rabi-driven qubit is new. This modulation is achieved by precisely combining the qubit's Rabi drive and sideband tones on the associated resonator mode(s).

To squeeze a single mode, these sideband drives are carefully calibrated from the resonator frequency to the modulation frequency. This regulated Jaynes-Cummings interaction produces the compressed states needed. It shifts the harmonic mode quadrature over time. The squeezing effective Hamiltonian shows how the qubit state, denoted by, directly controls the squeezing process. Applying the two bottom sidebands to one mode and the two upper sidebands to another allows entangled squeezing over two light modes.

This Rabi-driven qubit application offers many advantages and innovations:

Creating conditional squeezing is a major advance. This suggests that the qubit's state directly impacts compressed state direction or features. Because of its conditional nature, the qubit and oscillator can get entangled, making the qubit's state connected to the compressed direction. If the qubit is initialised in superposition, the composite system becomes entangled, and the squeezing direction depends on the post-selected qubit state. This “provides an additional layer of control” over quantum systems. Universal Bosonic State Control: Its biggest impact may be “universal control” over photonic (light) states, which this research enables. Universal control implies the ability to repeatedly apply a given set of Hamiltonians to perform any quantum operation in Hilbert space. The Rabi-driven qubit enables this unique conditional-squeezing operation, which controls quantum harmonic oscillators universally, even while displacement and squeezing actions are insufficient. Combining this squeezing operation with qubit manipulations like rotations and displacements and commutation relations yields a richer set of polynomial operators, including controlled-displacement operators and higher-order terms. This allows more complicated quantum algorithms and protocols. Efficiency and Intra-cavity Generation: This approach generates compressed states “intra-cavity” instead of using external devices. Creating compressed states in the system where they will be used reduces signal loss during travel. Due to photon loss, squeezed states are very efficient and resilient when their travel distance is reduced. This technology uses a Rabi-driven qubit to dynamically decouple it from low-frequency noise. This increases qubit dephasing time, enhancing the system's noise resilience. Needs No Kerr Nonlinearity: Simulated squeezing intensities reach 12 dB for two-mode and 13.5 dB for single-mode. Unlike Kerr nonlinearity, which can distort states but is often used in other squeezing methods, this is achieved without it. This allows for clearer, more precise squeezed states. View Quantum Blockchain News: Latest Updates, Security, and Impact.

The proposed plan is for current circuit QED Quantum Electrodynamics systems. Dispersive transmon qubits are connected to improved superconducting resonators to build these platforms. Simulations of single-mode squeezing used realistic experimental settings including a dispersive shift of -50 kHz and a Rabi frequency of 40 MHz. Squeezing was achieved in 20 µs, far less than the lifespan of current transmon-cavity devices. The simulation showed that two-mode squeezing achieved a maximum of 12.1 dB in approximately 33 µs.

Despite promising predictions, the squeezed superposition's amplitude is limited. These limits stem from theoretical modelling approximations, particularly the Rotating Wave Approximation (RWA). The RWA, which simplifies the Hamiltonian by disregarding swiftly oscillating sections, only applies for certain photon number (n) conditions in the resonator. Thus, the compressed state can contain only a limited number of photons before “higher-order terms come into effect” and the approximations fail.

The Magnus expansion, which estimates the effective squeezing Hamiltonian, limits the photon number by requiring the interaction intensity to be less than the modulation frequency. These higher-order effects may limit the amplitude of a superposition of entangled squeezed states to around 4 dB, hindering conditional squeezing.

The team plans to mitigate these higher-order corrections to increase squeezing and apply the technology to more complex multi-mode systems for quantum states engineering. Despite not including decoherence concerns in the simulations, given transmon-cavity advancements, it is thought to be challenging, but not impossible, to accomplish the simulated findings in an experiment.

In conclusion