The history of computers is intertwined with the history of modern technology. It all began in the 19th century, when, in 1801, a French merchant and inventor, Marie Jacquard, invented a loom with punched wooden cards to automatically weave fabric designs.
However, the most significant progress in automated computing that century occurred when English mathematician Charles Babbage devised a steam-driven calculating machine capable of computing tables of numbers. The most groundbreaking 20th-century invention came in 1936 from Alan Turing, a British scientist and mathematician, who introduced a universal machine, later named the Turing Machine. Scientists assert that the concept of modern computers is fundamentally based on Alan Turing”s ideas.
Since then, it has been a chain of progress. In 1939, David Packard and Bill Hewlett founded the Hewlett Packard Company, and in 1953, Grace Hopper developed the first computer language, COBOL, followed by John Backus and his team of programmers at IBM publishing a paper describing their newly created FORTRAN programming language.
The stream of inventions enriching computing technology over the years has focused on multiple aspects. Sometimes, it has been the development of a breakthrough language or software and, other times, crucial hardware. Such inventions continue to happen, helping to build the next generation of computers, something ably ‘futuristic,’ in the truest sense of the term.
In the following segments, we will look at two such inventions that involve Quantum Emitters and Infrared Lasers.
Moving Towards a Major Breakthrough: A Scalable Quantum Computer
The achievement comes from a team of researchers led by Lawrence Berkeley National Laboratory (Berkeley Lab). The researchers claim to have emerged successful in their attempt to use a femtosecond layer to create and ‘annihilate’ qubits by doping silicon with hydrogen. The researchers emphasized that they could carry out this exercise on demand and with precision.
But, to be able to realize the significance of the research to its fullest, we must know what qubits are and why they are important!
The Need to String Billion of Qubits Together
Quantum computers could prove pathbreaking in their ability to solve problems a million times faster than some of the most advanced supercomputers currently available. These machines have the potential to usher in revolutionary breakthroughs in areas such as healthcare, pharmaceuticals, and artificial intelligence. But for all these to happen, the industry would have to devise a way to string together billions of qubits or quantum bits, leading to the ultimate development of a highly efficient network of quantum computers.
The research has now shown a way to empower quantum computers by using programmable optical qubits or ‘spin-photon qubits’ that can connect quantum nodes across a remote network.
While explaining the significance of the research and the results it obtained, Kaushalya Jhuria, a postdoctoral scholar in Berkeley Lab’s Accelerator Technology & Applied Physics (ATAP) Division, made the following remark:
“To make a scalable quantum architecture or network, we need qubits that can reliably form on-demand, at desired locations, so that we know where the qubit is located in a material. And that’s why our approach is critical. Because once we know where a specific qubit is sitting, we can determine how to connect this qubit with other components in the system and make a quantum network.”
But how does the research achieve this objective? It does so by forming qubits in silicon with programmable control.
The Story of Silicon’ Color Centers’ and ‘Spin Photon Qubits’
With support from DOE’s Office of Science, the study used a gas environment to create programmable defects known as “color centers” in silicon. These color centers are candidates for “spin photon qubits” or special telecommunications qubits.
Quantum or qubit bit is a basic unit of quantum information. This smallest component of a quantum information system encodes data in 1, 0, or everything between them, which is known as superposition. Spin photon qubits, meanwhile, emit photons with the ability to carry information encoded in electron spin across large distances.
Now, to form these special qubits that can help support a secure quantum network precisely, the study utilized an ultrafast laser capable of emitting energy pulses in mere femtoseconds—each pulse as brief as a quadrillionth of a second, targeted to an area no larger than a dust particle.
On probing the optical (photoluminescence) signals of the resulting color centers using a near-infrared detector with the purpose of characterizing them, the team found a Ci center, which is a quantum emitter. The Ci center has a simple structure and promising spin properties while being stable at room temperature, making it a pretty impressive spin photon qubit candidate that emits photons in the telecom or frequency band. According to Jhuria:
“We knew from the literature that Ci can be formed in silicon, but we didn’t expect to actually make this new spin photon qubit candidate with our approach.”
Interestingly, increasing the femtosecond laser intensity when processing silicon in the presence of hydrogen can also increase hydrogen’s mobility. This, in turn, passivates undesirable color centers while leaving the silicon lattice undamaged.
A theoretical analysis also confirmed the experiment observations that the brightness of the Ci color center can be enhanced substantially in the presence of hydrogen. As Jhuria explained, the laser pulses can not just kick out but also bring the hydrogen atoms back, “allowing the programmable formation of desired optical qubits in precise locations.”
Reliably making color centers is simply the beginning; now, the team wants to get different qubits to talk to each other and see which ones perform the best.
“The ability to form qubits at programmable locations in a material like silicon that is available at scale is an exciting step towards practical quantum networking and computing.”
– Cameron Geddes, Director of the ATAP Division
The technique will next be used to incorporate optical qubits in quantum devices like waveguides as well as find new spin photon qubit candidates with properties optimized for selected applications.
New Approaches to Achieve Quantum Computing: Working with Molecules
The field of quantum computing has gained significant traction over the years, with researchers constantly working on finding new techniques to make it happen. Manipulating organic molecules is a field being studied for its potential application in quantum computing.
The team at TU Graz investigated how to stimulate competent molecules using infrared light pulses to create small magnetic fields. If this technique is further developed successfully in experiments, it can even be utilized in quantum computer circuits.
This is because selective manipulation of infrared light actually makes it possible to control the direction and strength of the magnetic field. Doing this converts molecules into high-precision optical switches, which can then even be used to build circuits for a quantum computer, according to Andreas Hauser from the Institute of Experimental Physics at TU Graz.
While interactions between molecular vibrations and spin magnetism are well-documented in microwave spectroscopy, this study proposes methods to actively excite molecular vibrations that generate a magnetic field at targeted locations.
Stimulating Molecules by Infrared Lasers to Form Magnetic Fields
When irradiated with infrared light, molecules start to vibrate due to the energy supply. Utilizing this phenomenon as the starting point, physicists started working on finding out if these vibrations could, in fact, be used to generate magnetic fields.
For their calculation, Hauser, along with his team, used metal phthalocyanines as an example. The team found that due to the high symmetry of these ring-shaped, aromatic planar dye molecules, they do generate tiny magnetic fields in the nanometre range (< 1 nm) when exposed to infrared pulses. Based on this, measuring the strength of the low but precisely localized field via nuclear magnetic resonance spectroscopy should be achievable.
Besides drawing on the work from laser spectroscopy’s early days, the team also used modern electron structure theory on supercomputers to compute how macrocyclic phthalocyanine molecules act when exposed to light via circularly polarized infrared light.
The team found that circularly polarized light waves excite two molecular vibrations simultaneously at right angles to each other. Liking this to the rumba technique, Hauser explained:
“The right combination of forwards-backwards and left-right creates a small, closed loop. And this circular movement of each affected atomic nucleus actually creates a magnetic field, but only very locally, with dimensions in the range of a few nanometres.”
This is all just theoretical, though. The team will now work on proving that molecular magnetic fields can be generated in a controlled manner experimentally so that they can actually be utilized.
For the experiment, however, they need to identify a substrate that interacts minimally with the targeted processes since upcoming applications necessitate positioning the phthalocyanine molecule on a surface. Doing so, however, alters the physical conditions, which then impacts the excitation brought out by light and the magnetic field’s characteristics.
So, before it can really be tested in experiments, the team has to first calculate the interplay between the deposited phthalocyanines, the infrared light, and the support material. If the experiment confirms the predicted changes in magnetic shielding constants, the study says, it can be seen as the first measurement of a magnetic field created vibrationally, with intramolecular resolution.
Click here to learn about Heron & Condor, the latest advancements in quantum computing.
Companies Advancing the Field of Quantum Computing
There are several companies, such as Microsoft, Intel, and D-Wave, that are working on advancing quantum computing. IBM is a prominent name that has been focusing on quantum computing for many years now. Just recently, it partnered with Japan’s National Institute of Advanced Industrial Science and Technology (AIST) to help the latter produce a quantum computer containing 10,000 qubits before this decade is over. So, amidst all this development, let’s take a deeper look at some other important names in the sector:
#1. Google
The tech giant has been putting a lot of effort into building quantum computers for the past many years. Back in 2019, Google demonstrated for the first time that quantum computers could run an algorithm that would be impossible for a conventional supercomputer to tackle.
Last year, Google’s Sycamore quantum processor was presented with 70 qubits, a leap from its previous version’s 53 qubits. This makes it about 241 million times faster and more robust than the previous model. Google’s new quantum computer, meanwhile, simulates the behavior of magnets in great detail and can help us gain a deeper understanding of magnetism.
In regards to quantum computing, Google uses a full stack approach, which encompasses the seamless integration of hardware and software components. The company is currently running a 3-year, $5M global competition called XPRIZE Quantum Applications to advance the field of quantum algorithms.
With a market cap of $2.2 trillion, Google shares are trading at $177.08, up 26.88% YTD. It has an EPS (TTM) of 6.52, a P/E (TTM) of 27.18, and a dividend yield of 0.45%. For Q1 2024, the company posted revenues of $80.5 billion, up 15% YoY, while its operating margin expanded to 32%.
#2. Dell
This technology company has also begun taking some concrete steps in quantum computing. Recently, Dell introduced a hybrid classical/quantum platform developed with IonQ. It also announced a collaboration with Aramco to explore advancements in quantum computing, AI, and edge computing. Together, Aramco and Dell aim to address complex challenges in the fields of energy optimization, weather modeling, materials science, and predictive maintenance through quantum computing.
According to Dell Technologies Ireland MD Catherine Doyle, quantum computing will also help in AI advancements as it “becomes intertwined in the near future.”
With a market cap of $100.74 billion, Dell shares are currently trading at $144.50, up 85.66% YTD. It has an EPS (TTM) of 4.36, a P/E (TTM) of 32.55, and a dividend yield of 1.25%. For Q1 2024, the company posted $22.2 bln in revenues and $60 million in net income.
Conclusion
Quantum computing has been a growing area of interest for researchers, organizations, and governments. Due to its ability to offer fast speed, enhanced security, more efficiency, accurate simulation, and improved analysis, it makes sense that there has been an increased focus along with continued research and investment, which may finally see quantum computing becoming a reality and finding its application across sectors.
Click here to learn about the current state of quantum computing.