#spatiallightmodulators

HiPARS: Highly Parallel Atom Rearrangement Sequencer Quantum Research Update: HiPARS Allows High-Parallel Atom Rearrangement for 1000-Qubit Scalable Neutral Atom Quantum Computing.

Neutral atom computing is a viable method for scalable quantum computation. Qubit atoms' initial states are challenging to produce. To address this barrier, Jonas Winklmann and Martin Schulz of the Technical University of Munich and their colleagues developed HiPARS, a revolutionary algorithm that speeds up and improves atom rearrangement. Traditional techniques' slow execution times and restricted parallel processing hinder the construction of accurate atomic configurations for safe quantum circuits. HiPARS, short for Highly-Parallel Atom Rearrangement Sequencer, overcomes these limits by employing highly-parallel “composite moves” to relocate numerous atoms over large distances. For near-term quantum devices with 1,000 qubits, this invention performs well. The Key Challenge of Scalable Qubit Preparation Neutral atom quantum computing research focusses on creating huge, faultless arrays of neutral atoms like Caesium or Rubidium as qubits for simulation and quantum computing. Quantum system scalability requires the capacity to build accurate arrays quickly and reliably while minimising defects. Many array-building methods have downsides. Despite its precision, optical tweezers are sluggish. However, optical lattices struggle to generate random configurations or rectify faults. Spatial light modulators (SLMs) are promising, but they require fast technology and strong algorithms. Current research emphasises the necessity for algorithms that limit sorting moves and correctly fix defects when using SLMs to build atom arrays. Several ways are being studied to parallelise array assembly and speed up the process. Some attempts aim for a constant-time overhead assembly. Physical setup advancements like linear phase interpolation improve SLM light pattern quality. Automating assembly is also being done with specialised software. Researchers are utilising AI to speed up assembly and achieve this constant-time overhead aim to push neutral atom quantum computing by producing massive, defect-free atom arrays. Parallel Composite Moves with HiPARS After finding current rearrangement methods were slow and unscalable, the team focused on improving atom shifting efficiency. This method eliminates a major field bottleneck and prepares qubits for computing. HiPARS uses highly parallel “composite moves” as its foundation. Despite their distance, the mechanism picks up and moves several atoms at once. The experimental setup for this novel approach uses acousto-optic deflectors to trap neutral atoms. Initially, atoms are randomly placed in an array. Its purpose is to efficiently sort randomly loaded atoms into a fully inhabited sub-area. The researchers substituted a greedy algorithm for predefined ones. This innovative technique dynamically selects the best move at each stage to maximise target site filling per execution time. This technique requires a configurable cost function to accurately determine the time needed for any transfer, taking into account distance and atom count. HiPARS's ability to offer complex, parallel moves (composite moves) and faster, direct actions makes it revolutionary. This flexibility lets the system dynamically adjust to each sorting phase's needs. This discovery should reduce the time needed to initialise quantum operations, shifting the computational barrier from atom sorting to computing. Fast and Scalable Metrics The novel method allows multiple qubits to be transferred simultaneously by maximising atom parallel movement. The algorithm recognises complex, composite moves that lift and move many atoms in one efficient phase.

OAM orbital angular momentum Twisted light reveals relativistic motion in the universe

Fazilah Nothlawala and her Glasgow University colleagues, along with scientists from the University of the Witwatersrand and Heriot-Watt University, have developed a new method to accurately measure relativistic effects like Lorentz contraction factors by observing the “twist” in entangled light. This innovative idea uses light's fundamentals. By extending orbital angular momentum (OAM) metrology into special relativity, this unique method may be more precise and versatile than existing methods for measuring speeds near the speed of light.

According to Einstein's theory of relativity, light's characteristics change when viewed from a moving perspective. One of the theory's more perplexing predictions is length contraction, which occurs when things appear shorter as their velocity rises. Until previously, measuring these affects directly was impossible, especially under extreme conditions.

The orbital angular momentum (OAM) of light drives this novel technique. OAM describes the helical twist that gives photons their “twist”. Because OAM is not Lorentz invariant, its properties rely on detection speed. This non-invariance makes OAM a sensitive relativistic motion probe. The Quantum Evangelist from one source says quantum mechanics “is a way of understanding the world at its most fundamental level” and “challenges our preconceptions.” This study embodies such spirit.

Researchers used the relationships between entangled photon pairs whose features are naturally related. Entangled photons were created via Spontaneous Parametric Down-Conversion (SPDC), in which a pump laser interacts with a nonlinear crystal to create two new photons. They photographed the crystal's plane with two SLMs.

The primary finding of the study is that length contraction alters OAM spectrum correlations of entangled photons viewed at different speeds. The spatial rescaling caused by relativistic motion changes the orthogonality of OAM waveforms. Consequently, OAM spectrum broadens. As the Lorentz factor grows or speed approaches light speed, the OAM spectrum widens and orthogonality breaks.

The group demonstrated this with a simulation. To simulate relativistic length contraction, they encoded distorted detecting modes with spatial light modulators (SLMs) as "contracted detectors". They calculated the joint probability distribution of the observed OAM modes of the entangled photon pairs to quantify this broadening. The experimental setup confirmed the theoretical predictions, showing a direct link between the expected Lorentz factor and OAM spectrum alterations.

The group mathematically linked the OAM spectrum to the Lorentz factor. They showed that the Lorentz factor may be extracted from OAM measurements' conditional probabilities. For a range of encoded Lorentz factors, from rest frame to empirically measured joint probability spectra, theoretical predictions matched experimental results. This allowed scientists to mimic velocities up to 0.99c (99% of light speed) in the lab and quantitatively derive the Lorentz (contraction) factor.

Due to this work, metrology has evolved greatly. OAM's non-Lorentz invariance and structured light's properties have allowed the researchers to measure precisely in severe conditions. The findings lay the groundwork for relativistic measuring methods.