To process information, photons must interact. However, these tiny packets of light want nothing to do with each other, each passing by without altering the other. Now, researchers at Stevens Institute of Technology have coaxed photons into interacting with one another with unprecedented efficiency — a key advance toward realizing long-awaited quantum optics technologies for computing, communication and remote sensing.
The team, led by Yuping Huang, an associate professor of physics and director of the Center for Quantum Science and Engineering, brings us closer to that goal with a nano-scale chip that facilitates photon interactions with much higher efficiency than any previous system. The new method, reported as a memorandum in the Sept. 18 issue of Optica, works at very low energy levels, suggesting that it could be optimized to work at the level of individual photons — the holy grail for room-temperature quantum computing and secure quantum communication.
“We’re pushing the boundaries of physics and optical engineering in order to bring quantum and all-optical signal processing closer to reality,” said Huang.
To achieve this advance, Huang’s team fired a laser beam into a racetrack-shaped microcavity carved into a sliver of crystal. As the laser light bounces around the racetrack, its confined photons interact with one another, producing a harmonic resonance that causes some of the circulating light to change wavelength.
That isn’t an entirely new trick, but Huang and colleagues, including graduate student Jiayang Chen and senior research scientist Yong Meng Sua, dramatically boosted its efficiency by using a chip made from lithium niobate on insulator, a material that has a unique way of interacting with light. Unlike silicon, lithium niobate is difficult to chemically etch with common reactive gases. So, the Stevens’ team used an ion-milling tool, essentially a nanosandblaster, to etch a tiny racetrack about one-hundredth the width of a human hair.
Before defining the racetrack structure, the team needed to apply high-voltage electrical pulses to create carefully calibrated areas of alternating polarity, or periodic poling, that tailor the way photons move around the racetrack, increasing their probability of interacting with eachother.
Chen explained that to both etch the racetrack on the chip and tailor the way photons move around it, requires dozens of delicate nanofabrication steps, each requiring nanometer precision. “To the best of our knowledge, we’re among the first groups to master all of these nanofabrication steps to build this system — that’s the reason we could get this result first.”
Moving forward, Huang and his team aim to boost the crystal racetrack’s ability to confine and recirculate light, known as its Q-factor. The team has already identified ways to increase their Q-factor by a factor of at least 10, but each level up makes the system more sensitive to imperceptible temperature fluctuations – a few thousands of a degree – and requires careful fine-tuning.
Still, the Stevens team say they’re closing in on a system capable of generating interactions at the single-photon level reliably, a breakthrough that would allow the creation of many powerful quantum computing components such as photonics logic gates and entanglement sources, which along a circuit, can canvass multiple solutions to the same problem simultaneously, conceivably allowing calculations that could take years to be solved in seconds.
We could still be a while from that point, Chen said, but for quantum scientists the journey will be thrilling. “It’s the holy grail,” said Chen, the paper’s lead author. “And on the way to the holy grail, we’re realizing a lot of physics that nobody’s done before.”
The Latest on: Quantum computing chips
via Google News
The Latest on: Quantum computing chips
- Quantum computing’s also-rans and their fatal flawson November 30, 2019 at 7:00 am
A practical quantum computer requires that we can create many quantum bits (qubits ... through nearby wires but simultaneously isolating the effects so that they don't influence other qubits.
- A Reality Check on Quantum Computerson November 29, 2019 at 7:30 am
Currently, the vast majority of computers are machines that process huge arrays of 0s and 1s ... Vacuum tubes and electromagnetic relays gave way to modern integrated circuits, which pack billions of ...
- The Golden Age Of Ever-Changing Computer Architectureon November 27, 2019 at 7:05 am
Concepts such as neuromorphic computing, probabilistic computing, and quantum chips are making their way from theory to development. Neuromorphic computing uses low-power artificial synapses to mimic ...
- The past, present and future of computing in high-energy physicson November 26, 2019 at 1:22 am
What about quantum computers? What impact will they have on high-energy physics ... More recently, though, computing power has gone up because of increases in the number of transistors on a chip, ...
- The Quantum Era Is Coming, But It’s Not Here Yeton November 25, 2019 at 8:56 pm
We’re in a similar phase in quantum computing where we do have quite a few companies investing in it, including D-Wave, IBM, Intel, Google, Microsoft, Rigetti, and others. While machine learning and ...
- Protection from attacks by quantum computers: DFKI starts project for long-term encryption of medical dataon November 25, 2019 at 3:39 am
An important part in this QC resistance is the secure element (SE), a chip that guarantees the protection of processed data in a device and therefore plays a vital role during a possible attack by a ...
- Quantum Volume: A Yardstick To Measure The Performance Of Quantum Computerson November 23, 2019 at 6:40 pm
Jay Gambetta, IBM Vice President, Quantum Computing, posted graphs online showing progressive improvement in CNOT error rates as a result of various changes. In the post, he said: "With four revisions ...
- Quantum technology comes of ageon November 22, 2019 at 8:39 am
Using electromagnetic fields, IonQ deploys and traps atomic qubits on a silicon chip within ultra-high vacuum chambers to create what the company calls the world’s first commercial trapped-ion quantum ...
- Electric field spectroscopy of material defects in transmon qubitson November 22, 2019 at 3:39 am
Superconducting integrated circuits have demonstrated a tremendous potential to realize integrated quantum computing processors. However ... Actually, a single electrode that is biased against the ...
- Quantum Generative Adversarial Networks for learning and loading random distributionson November 22, 2019 at 2:42 am
Finally, we employ the generator trained with a real quantum computer to conduct QAE-based option pricing ... Full size table Notably, some of the more prominent fluctuations might be due to the fact ...
via Bing News