Slow Connections, Fast Results: The Future of Distributed Quantum Computing

Researchers at IonQ and Aalto University have proved that multiple quantum processing units (QPUs) connected through slow interconnects can outperform single large quantum computers. This matters because building connections between quantum computers is much harder than making the computers themselves faster.

A qubit is the basic unit of quantum computing, similar to how a bit is the basic unit of regular computing. But while a regular bit is either 0 or 1, a qubit can be both 0 and 1 simultaneously until measured. This property lets quantum computers solve certain problems much faster than conventional computers.

Think of the challenge like trying to solve a puzzle. You could build one giant table and work alone, or you could connect several small tables with people working together. The catch: passing puzzle pieces between tables takes much longer than placing them on your own table.

Current quantum computer links are roughly 100 times slower than operations inside a single machine. Most experts assumed this speed gap made connected systems impractical. The IonQ and Aalto University team proved otherwise.

Their solution uses a clever technique called distributed CliNR (Clifford Noise Reduction). Instead of waiting for slow connections during the main computation, they prepare verified components in parallel on separate machines. Each quantum computer works independently on its piece, then they connect the results only when needed. This reduces both errors and total computation time.

The researchers tested their approach using 85 qubits split across four quantum computers. Even when connections were five times slower than internal operations, the distributed system beat both the direct approach and the single-machine version in speed and accuracy.

The math shows you only need modest connection speeds. For t quantum computers, you need roughly t/ln(t) parallel connections. This grows much slower than the number of machines, making the approach scalable.

Why this matters now: experimental quantum networks already exist but produce entangled pairs every 4-5 milliseconds while internal gates take microseconds. Rather than waiting for faster connections, useful multi-computer systems can now be built.

The work provides blueprints for near-term distributed quantum computers and identifies potential applications including quantum superiority experiments. These experiments demonstrate that quantum computers can solve specific problems that would take conventional supercomputers impractically long to solve, proving quantum computers have crossed a meaningful performance threshold.

This research shows that slow connections are not a dealbreaker for quantum networking.

Building Quantum Networks on Existing Fiber Infrastructure

Image AI Generated

I’ve written here about quantum networks and communications. These systems that connect quantum computers and devices using quantum entanglement hold enormous promise for secure communication and distributed computing. But getting them to work over real-world distances has proven challenging.

The problem comes down to wavelengths. Most quantum systems today use visible or ultraviolet light to create entanglement between atoms. But here's the catch: when you try to send these signals through fiber optic cables over long distances, they degrade rapidly. The sweet spot for fiber optics is the "telecom band" - wavelengths ranging from about 1,260 to 1,675 nanometers or nm (infrared light), with the most efficient transmission around 1,310 nm and 1,550 nm. At these wavelengths, signals can travel hundreds of kilometers with minimal loss.

Converting quantum signals from visible light to telecom wavelengths sounds like an easy fix, but it's not. The conversion process reduces efficiency and introduces errors that corrupt the delicate quantum states you're trying to preserve.

Researchers led by Prof. Jacob P. Covey at the University of Illinois have identified a solution described here: A new scalable approach to realize a quantum communication network based on ytterbium-171 atoms The solution uses ytterbium-171 atoms that naturally emit light at 1,389 nanometers—already in the telecom band. No conversion needed. It's like building a device that speaks the right language from the start.

Ytterbium-171 was chosen strategically. This isotope is already used in ultra-precise atomic clocks because it has an extremely stable internal state. The researchers realized they could exploit this stability for quantum networking while taking advantage of its telecom-compatible light emission.

What makes this work particularly significant is the team's approach to scaling. Instead of just connecting one atom at a time, they created an array of multiple ytterbium-171 atoms held in place by focused laser beams (called optical tweezers). They then aligned this array with standard fiber optic cables - similar to how you might plug multiple ethernet cables into a router. This parallelization means multiple quantum connections can be established simultaneously, like having multiple lanes on a highway instead of a single narrow road. The team demonstrated that all channels maintained high-quality entanglement with virtually no interference between neighboring connections - a critical requirement for practical networks.

The researchers used something called "time-bin encoding" to package their quantum information. Rather than encoding data in properties like light polarization (which can get scrambled in fiber), they encode it in the precise timing of when photons arrive. Think of it as Morse code at the quantum level - the message is in the timing pattern rather than the brightness or color.

One innovation that makes this practical is their "mid-circuit networking protocol." In quantum computing, one of the biggest challenges is that quantum states are fragile—they degrade quickly. This protocol allows the system to establish network connections while keeping other quantum data intact, like being able to download files on your computer without closing all your other programs.

The team demonstrated their system can:

·       Create high-quality entanglement between atoms and photons consistently across all channels

·       Maintain quantum connections after sending photons through 40 meters of fiber optic cable

·       Achieve entanglement fidelity approaching 99% with planned improvements

·       Operate multiple channels simultaneously without crosstalk

The researchers are already designing a second-generation system that will use optical cavities (essentially mirrors that bounce photons back and forth) to dramatically improve collection efficiency. This could increase networking rates by orders of magnitude.

The long-term vision is creating networks where quantum processors at different locations can share entanglement - enabling distributed quantum computing, synchronized arrays of atomic clocks for precision sensing, and fundamentally secure communication channels.

This work shows that quantum networks can be built using existing fiber optic infrastructure while maintaining the high fidelities needed for practical quantum applications. By combining telecom-compatible atoms with scalable parallel architecture, the team has created a roadmap for the quantum networks of the future.

How 6G Will Improve on 5G in the Same Spectrum

A couple years ago, I spent some time developing 5G wireless technology content for faculty to use in their classrooms. Here comes the next generation.... 6G…. and (of course) AI is playing a major role in network management.

The transition from 5G to 6G represents more than just a numerical increment—it's a
fundamental rethinking of wireless network design. Many people believe new spectrum bands are needed for meaningful improvements between generations but the situation is more complex. The radio waves used by 5G in its sub-6 GHz and mmWave 24-40 GHz bands can be utilized more efficiently by 6G technology to achieve significant performance improvements. These enhancements would represent fundamental changes to network reliability and capacity and intelligence rather than minor adjustments without needing costly spectrum license purchases. The innovations would emerge from rethinking both signal transmission physics and network management intelligence. 

Advanced MIMO Systems: 6G technology could implement massive arrays with 1,000+ elements to generate extremely precise beams which reduce interference and boost capacity beyond the 5G maximum of 64-128 antenna elements. 

Smarter Waveforms: The waveform technology in 6G would surpass OFDM by implementing adaptive waveforms which modify their patterns according to environmental conditions. The system functions like an automobile which adjusts its body shape to achieve better aerodynamics during specific situations. 

AI Network Management: Like recent advancement in 5G, 6G networks will employ AI to forecast user activities and data requirements so they can distribute resources before users initiate their requests. 

Cell-Free Architecture: Your device would establish simultaneous connections with multiple transmission points which work together to provide seamless coverage throughout the network. The 6G radio technology functions as an environmental sensor to help the network optimize signal paths through its ability to detect physical obstacles and movement patterns. 

When We'll See It: Based on historical wireless technology evolution patterns and current industry roadmaps, commercial 6G networks are likely to launch around 2030-2032, following a progression similar to previous generations:

·      Initial technical requirements and vision documents are already being developed (2023-2025)

·      Research and standardization work will accelerate through 2026-2028

·      The first official 6G specification (3GPP Release 20 or 21) is expected around 2028-2029

·      Early trial deployments would follow in 2029-2030

·      Commercial availability would begin in leading markets by 2030-2032

Several major telecommunications companies including NTT DoCoMo, Samsung, and Huawei have published 6G whitepapers targeting 2030 for initial deployment. Various international research initiatives like the EU's Hexa-X project and China's national 6G promotion group are working toward this timeline.

6G's improved features would achieve 2-3 times better efficiency without spectrum expansion but the largest benefits would emerge from incorporating additional high-frequency bands.

The Birth of Modern Computer Communications: The Hayes Smartmodem

Another looking back post - it was 1982, and I was still trying to figure out what I wanted to do in life. At one time I thought I wanted to go to medical school but after working in a hospital microbiology lab, I realized that was not the path for me. Maybe I could do something in the communications field….

In the early 1980s, connecting computers over phone lines was a complex and frustrating process requiring specialized knowledge and equipment. That all changed in 1981 when Dennis Hayes and Dale Heatherington introduced the Hayes Smartmodem, a revolutionary device that would fundamentally transform how computers communicate. The Hayes Smartmodem 300 was the first modem to combine communication hardware with an intelligent microprocessor control system. Unlike previous modems that required manual configuration, the Smartmodem could be controlled through a standard command set—the now-famous "AT commands" (where AT stood for "Attention"). This innovation allowed software to directly control the modem, automating the complex process of establishing connections.

The AT Command Revolution

The AT command set, sometimes called the Hayes command set, revolutionized communications because it created a standardized way for computers to control modems through simple text commands.

 

Basic Structure and Function

AT commands follow a simple structure: they begin with "AT" followed by specific command
letters and parameters. For example:

·      ATD (Dial) - Instructs the modem to dial a number

·      ATH (Hang up) - Terminates the current connection

·      ATA (Answer) - Instructs the modem to answer an incoming call

·      ATZ (Reset) - Resets the modem to its default configuration

The genius of this system was its simplicity. Before Hayes, controlling modems required specialized hardware interfaces or complicated software. The AT command set turned modem control into simple text strings that any program could generate.

Historical Impact

When Dennis Hayes introduced this command set with the Smartmodem in 1981, he effectively created the first "smart" modem that could be programmed and controlled by software. This innovation:

• Allowed software to handle complex connection procedures automatically
• Enabled features like auto-dialing and auto-answering
• Created a standard that was widely adopted across the industry
• Made modems accessible to non-technical users

Legacy and Modern Applications

Remarkably, variants of the AT command set are still used today in many communication devices. Modern cellular modems, some smartphones, and IoT devices continue to use AT commands for configuration and control. For example, sending an SMS from some embedded systems still involves AT commands like AT+CMGS.

The AT command set represents one of those rare technological innovations that was so fundamentally sound that its basic principles have outlived the hardware for which it was originally designed. From controlling 300 bps modems in the early 1980s to configuring LTE and 5G modules today, the basic concept of "Attention + Command" has proven remarkably durable.

This standardization was perhaps the Hayes Smartmodem's most enduring contribution to computing history - creating a common language that allowed computers and communication devices to work together seamlessly, helping to build the connected world we know today.

Quantum Communications - Part 3: Photon Polarization and Superposition

 Building on Part 2’s discussion of polarization, let's look a little deeper at how light enables quantum communication. Superposition in quantum mechanics means a photon can exist in multiple polarization states at once, unlike classical objects that must be in one definite state. Looking at the diagram below, a photon isn't limited to being just vertical (1) or horizontal (0), but can exist in a mixture of both until measured. Think of it like a spinning coin - while spinning, it's neither heads nor tails but both possibilities at once. When we measure the photon's polarization (like catching the coin), it "collapses" into one definite state.

The diagram shows two measurement bases - rectilinear and diagonal. A photon in superposition measured in either base has a probability of being found in either state of that base. This property is crucial for quantum cryptography because any measurement by an eavesdropper forces the superposition to collapse, altering the photon's state and revealing the intrusion.

 

The 45° polarization state, shown in the diagonal base of our diagram, demonstrates one of the most fascinating aspects of quantum mechanics. While we might classically think of 45° as simply an angle halfway between horizontal and vertical, in quantum mechanics it represents something far more profound. When a photon is polarized at 45°, it literally exists in a perfect blend of horizontal and vertical states at the same time - not just leaning one way or the other, but fully in both states simultaneously.

 

This quantum behavior becomes clear when we measure these 45° polarized photons. If we measure using the rectilinear base (horizontal/vertical as shown in the left circle of our diagram), we get the following result: the photon will randomly show up as either horizontal or vertical with exactly equal probability. This isn't because we're measuring imprecisely or because the photon was "kind of" in both states - it was genuinely, mathematically, and physically in both states at once until the act of measurement forced it to pick one.

 

Think of it this way: if we send many 45° polarized photons through a horizontal polarizer, exactly half will pass through (registering as horizontal) and half will be blocked (registering as vertical). This isn't due to some classical "angled" behavior - it's a direct manifestation of quantum superposition, where the photon existed in both states simultaneously until we forced it to "decide" by measuring it.

 

This property is part of what makes quantum communication so secure: any attempt to measure these superposition states unavoidably disturbs them, making eavesdropping detectable.

Quantum Communications - Part 2: Polarization

In Part 1 of this series I discussed how quantum superposition allows particles to exist in multiple states at once until measured. This makes quantum information almost impossible to copy secretly, enabling ultra-secure communication systems that can detect eavesdropping attempts. Here we'll take a closer look at how this information is transmitted using light particles called photons. 

Light can be analyzed as either a ray or a wave, each model revealing different aspects of its behavior. The ray model treats light as straight lines traveling through space, useful for understanding reflection, refraction, and how lenses and mirrors work. The wave model shows light as oscillating electromagnetic waves, explaining phenomena like interference, diffraction, and polarization. While the ray model helps us design simple optical devices like eyeglasses, the wave model is necessary for understanding more complex effects like how polarizing filters work. Both models remain important in modern optics, with each being used depending on which aspects of light's behavior are most relevant to the situation at hand.

 

When it comes to polarization we need to think about light as a wave. Light waves oscillate perpendicular to their direction of travel, Unpolarized light ( like we get from natural sources like the sun or artificial sources like light bulbs) vibrates in all possible directions like a rope being waved up-down, side-to-side, and at every angle in between. A polarization filter works like a microscopic venetian blind with extremely fine parallel slits. When light encounters the filter, only the waves that vibrate parallel to these slits can pass through completely. Waves vibrating in other directions are either blocked entirely or have only their parallel components transmitted. The light that emerges from the filter is polarized, meaning all the waves are vibrating in the same direction. 

Here's a quick 3 second video I made demonstrating light passing through a polarizing filter.

Before the filter: 

• Horizontal component (blue wave)
• Vertical component (pink wave)
• 45-degree component (green wave, thicker line) All components are present in the unpolarized light

The Filter: 

• Oriented at 45 degrees
• Only allows waves aligned with its transmission axis

After the filter: 

• Only the 45-degree component (green wave) passes through
• Horizontal and vertical components are blocked
• The transmitted light is polarized along the 45-degree axis

Notice:

• Only transmits light waves that oscillate parallel to its transmission axis (45 degrees in this case)
• Waves at other angles are either blocked or have only their 45-degree component transmitted
• The result is polarized light oscillating only at 45 degrees

This selective transmission property makes polarizing filters particularly useful in everyday applications. For example, polarizing sunglasses can effectively reduce glare because light reflecting off horizontal surfaces like water or roads tends to become partially polarized in the horizontal direction. The sunglasses, which have vertical polarizing slits, block this horizontal glare while still allowing other light through. A demonstration of how polarization works involves using two polarizing filters. When light passes through the first filter, it becomes polarized in one direction. If you then rotate a second filter 90 degrees relative to the first, no light gets through at all because the polarized light from the first filter is now perpendicular to the slits in the second filter.

 

So what does polarization have to do with quantum communications? In quantum communications individual photons can be prepared in specific polarization states (vertical, horizontal, or diagonal) to represent quantum bits. Due to quantum mechanics principles, any attempt to measure these polarization states disturbs them, making secure communication possible - eavesdropping can be detected. Polarization also enables quantum entanglement, where measuring one photon's polarization instantly determines its entangled partner's state, even at a distance.

 

While powerful, polarization methods face practical challenges as polarization states can degrade during transmission through optical fibers or atmosphere, requiring sophisticated error correction methods. For these reasons, quantum communications can use several alternatives to polarization for encoding quantum information. Time-bin encoding uses photon arrival times and works well in fiber optics where polarization degrades. Phase encoding utilizes phase differences between photon paths, while frequency encoding uses different photon frequencies. Orbital Angular Momentum (OAM) encoding exploits spiral patterns of light waves, potentially carrying more information than polarization. Path encoding, which uses different physical routes for photons, is useful in integrated photonic circuits. Each of these methods has its own advantages and the choice often depends on the specific application and transmission medium being used. For instance, time-bin encoding tends to be more robust for long-distance fiber communication, while OAM can potentially carry more information per photon. 

Quantum Communications – Part 1

 Computers, communications, photonics, cybersecurity…… some of my favorite technologies all bundled together in quantum communications! But… what is it? How does it work? Let's take an introductory look.

In quantum mechanics, something called superposition allows systems to exist in multiple states simultaneously - like a spinning coin being both heads and tails at once, until observed. Only measurement forces it into a definite state. This principle affects quantum information through the no-cloning theorem, which states that it's impossible to create an exact copy of an unknown quantum state due to quantum mechanics' mathematical foundations. This feature enables quantum key distribution (QKD), which creates unbreakable encryption keys. Any eavesdropping attempt disturbs the quantum states due to the no-cloning theorem, instantly revealing the intrusion. While classical information can be copied perfectly, quantum information's resistance to copying both protects it and makes quantum teleportation the only way to transfer quantum states.

 

How about an example? Let’s now compare sending a classical letter and sending a quantum letter using two diagrams I’ve created. These diagrams split into two parallel workflows showing classical versus quantum communication highlight the key security advantages of quantum communication over classical methods.

 

The classical letter path shows a letter that can be intercepted, read, and copied without detection as it moves from sender to recipient through the postal system.

The quantum letter path illustrates how quantum letters behave differently:

• The letter exists in superposition (blue state) until measured
• Any attempt to read/copy disturbs the quantum state (changes to red)
• This disturbance is detectable when received by the recipient, revealing tampering

We’ll dig a little deeper in future posts – for now think of quantum communication as the first step toward a quantum internet - one that operates on the powerful principles of quantum physics rather than classical physics. While we may not see quantum email on our phones anytime soon, the technology is steadily advancing from science fiction toward practical reality.

Communications, Networking Methods & Protocols: Introduction and the Information Asset

Terry Pardoe and I wrote an unpublished text titled Data Communications, Networking Methods and Protocols book 20 years ago. Terry passed away on May 2, 2016 at the age of 76. Over this summer I’ll be posting content from that unpublished book here in honor and respect of Terry. It is interesting – 20 years later - a combination of some obsolete but other still relevant technologies. Here’s the first post from the first chapter.

 

The creation and introduction of the binary digital computer into the world of information collection, processing and distribution has brought with it massive expansions in the speed of processing and the breadth of distribution. It has also brought new approaches to connection and an ever increasing need to construct and operate complex, multi vendor networks. Computer systems allow us to make complex information manipulations millions of times faster than by hand and reduce the risk that we make the same mistakes as we always did.

 

Before any attempt is made to analyze the creation and operation of networks ranging in size from ones covering a single household to global coverage we need to understand the evolving role of computers in the past, the present and the future and how our need to deliver computer power and information to a wide range of users has resulted in complex solutions utilizing a broad spectrum of computer types and transmission mechanisms. Such integration has made the use of standardized approaches of paramount importance

 

In this post we'll take a look at how computer systems, and information use,  have evolved into modern approaches and how the world of standards has ensured this transition from the simple to the complex.

 

The Information Asset

The collection, storage and maintenance of timely information over a wide range of types has been implemented over the centuries by a range of written book-keeping techniques that include wall paintings, scrolls, and both hand written ledgers and typed ledgers.

 

Within a corporation different types of information exist in many forms Corporate level information can include financial records, asset lists, customer profiles, product definitions and specifications, trend analyses, competition evaluations and much more. At the department level information can include function definitions, resource availability, staffing lists, technical specifications, schedules and other operational information. In addition, information such as personal schedules, travel support documents, operating procedures, usernames and passwords is typically collected and saved by individuals.

 

A corporation may also acquire and maintain personal and often private and sensitive information about it's employees including social security and tax information, educational background materials and work history. It may also save  information considered to be useful to the corporation from public sources. Trade laws and restrictions in overseas markets, climatic conditions in countries of operation, demographics, maps and travel instructions are all examples of this type of information. Such collection and storage of information has always presented a number of issues to management, the major ones being:

Ownership - Who, within the organization, owns the information and protects and certifies its accuracy.

 

Control - Who controls the information, its collection, it's use by whom, it's modification, also by whom and when, and its final elimination. (It should be noted that ownership and control may be vested in different individuals or organizational units.)

 

Distribution - How is information distributed, to whom, under what conditions, by what technical mechanisms and what controls are in place to prevent it from  being misused or falling in the wrong hands.

 

The key to successful information control lies in the selection or creation and consequent  implementation of a company wide suite of information standards. Many examples of such standards exist and have evolved over the ages addressing such issues as:

·      The infrastructure needed to create, maintain and use stored information resources.

·      The financial cost of creation, maintenance, protection and final elimination of all forms of information.

·      All machine (if used) and  human factors

·      Measures taken to eliminate the impact of all disasters, natural or manmade.

 

The goal with all collected and distributed information, whether it be stored as paintings on cave walls or detailed writings in ledgers, has always been to meet the objectives of what the authors have defined as the Information Bill of Rights.

• The right information

• To the right person or process

• At the right time

• In the right place

• In the right form and format

• At the right price