#photonicqubits

[govindhtech]

Amaravati State Quantum Mission ASQM for India’s Vision 2047

Amaravati State Quantum Mission

India is beginning a dramatic path to maintain its leadership in quantum science, a new technology. The nation is building top-notch infrastructure to boost innovation, industrial development, and national security with billions of rupees and aggressive state-level initiatives. From world-class research institutes to "Quantum Valleys," India is preparing to become a major quantum computing exporter.

The ₹6,003 Crore Foundation for Sovereignty

The National Quantum Mission (NQM), a ₹6,003 crore project recently approved by the Union Cabinet, is the movement's principal focus. The mission aims to create domestic capabilities in quantum computing, sensing, communication, and materials. The government is achieving this by building international-standard central and fabrication facilities in premier research universities.

Four quantum fabrication facilities at IIT Bombay, IISc Bengaluru, IIT Kanpur, and IIT Delhi will cost ₹720 crore, as announced by Union Minister of State for Science and Technology Dr. Jitendra Singh. Superconducting and photonic qubits are needed for domestic quantum development, and these facilities meet international quality criteria. India invests in this "sovereign ascent" to reduce its dependency on imported machinery and boost domestic innovation.

Amaravati Vision: India's First Full-Stack Ecosystem

State governments promote industry and commerce, while the federal government funds research. With the Amaravati Quantum Valley (AQV), Andhra Pradesh leads. This 50-acre “full-stack” quantum ecosystem integrates quantum computing, AI, semiconductor research, and defense innovation.

C.V. Sridhar, Mission Director of the Amaravati State Quantum Mission, said these measures will place India in the top 10 quantum technology nations. The AQV will center on an IBM cooperation to house an IBM Quantum System Two, India's largest quantum processor with a 156-qubit Heron processor. This center partners with TCS and L&T to market and integrate research findings into the economy.

Indigenous Manufacturing and Comparison

The infrastructure goes beyond PCs to support an independent ecosystem. To benchmark components, Andhra Pradesh is establishing a Quantum Reference Facility at an estimated cost of ₹40 crore. Amber Enterprises is investing ₹200 crore in a plant for quantum cryogenic components to address quantum technology production needs.

Non-government organizations like universities, startups, MSMEs, and the private sector can use these facilities. This joint technique bridges the "technology gap" to test and scale cutting-edge research domestically. Professionals expect innovations in climate modeling, cybersecurity, logistics, and healthcare.

Workforce Preparation for Deployment

India recognizes that hardware alone is insufficient and focuses on people capital. The NQM includes a strategy for training quantum physics experts.

The Andhra Pradesh government has instructed schools to teach quantum computing. At a recent Rayalaseema University Faculty Development Programme (FDP), educators were urged to prepare students for “Quantum City” hubs. The goal is to train a “deployment-ready” workforce that can support sensing, communication, and computing.

Road to 2047

The “Viksit Bharat-Viksit Andhra Pradesh 2047” national goal drives these investments. India intends to increase public administration's cyber resilience and transparency by building the first quantum governance framework, ensuring that technology serves the public while protecting national interests.

India is becoming a quantum technology supply hub as these international-standard facilities open. A successful quantum economy is developing from basic research, signaling that India will lead the deep-tech revolution.

[govindhtech]

EPB Quantum Computing Fellowship Backed by $4M NIST Grant

EPB has officially inaugurated a new Quantum Computing Fellowship meant to promote workforce development and secure Chattanooga’s status as a premier hub for quantum technology. The National Institute of Standards and Technology (NIST) has received a $4 million federal grant to support the program, which aims to provide participants the hands-on training and real-world experience they need to lead the “quantum future.”

The following takes an in-depth look at the fellowship’s aims, the strategic relationships engaged, and the broader economic repercussions for the East Tennessee region.

The Launch of the Quantum Computing Fellowship

EPB announced the introduction of its Quantum Computing Fellowship, a designed specifically geared to create a highly qualified workforce for the future quantum age. This fellowship is a direct response to the growing demand for experts in theoretical computer science and quantum information science.

By giving particular training, EPB intends to:

Build a Next-Generation Workforce: Training local people to grasp quantum physics and its applications. Solve Scientific Issues: Giving fellows the opportunity to work with sophisticated computational models to solve practical issues. Enhance Local Infrastructure: Directly benefiting EPB customers and the greater Chattanooga community through digital innovation. Janet Rehberg, the President and CEO-elect of EPB, termed the quantum computing fellowship as a “critical investment” that will keep the city’s innovation ecosystem on the “cutting edge”.

The NIST Grant and Federal Funding

This program relies on a $4 million NIST grant. EPB got the cash in 2024, but the fellowship began in early 2026.

This governmental investment underlines quantum technology’s rising importance to national security and economic competitiveness. The reward permits EPB to become a high-tech workforce development leader from a municipal electric business.

Strategic Collaboration with IonQ

IonQ, a renowned pioneer in the field of quantum computing, was actively involved in the design of the quantum computing fellowship program. Fellows get industry-leading skills and hardware under this arrangement.

The IonQ Forte Enterprise quantum computer, which was included into the EPB Quantum Center in downtown Chattanooga last year, is a significant piece of this relationship. This gear supplies the infrastructure required to perform research on:

Understanding the resources required to address various classes of computer problems is known as computational complexity theory. Models of Computation: Developing novel ways for computers to process information utilizing quantum physics. Information Theory: Advancing the study of how information is quantified, stored, and communicated in a quantum system.

Regional Impact and Political Support

The idea has gotten strong encouragement from Congressman Chuck Fleischmann, who has been a loud advocate for East Tennessee’s role in the quantum industry. According to EPB leadership, Fleischmann has "championed" the region's attempts to harness technological innovation to build the future of energy resilience and national security.

The fellowship is designed to function as a magnet for talent, luring researchers and tech professionals to the region while also supporting the local Economy of Chattanooga. By promoting the city as a center for Public Utilities innovation, EPB is exploiting its existing broadband and energy infrastructure to drive a new generation of industrial growth.

The Broader Quantum Landscape

The EPB fellowship is being established at a time when the US quantum industry is witnessing a lot of activity. While EPB focuses on workforce and municipal applications, other companies are looking to expand quickly through mergers and acquisitions.

For example, Luminar Semiconductor Inc. was recently acquired by Quantum Computing Inc. This consolidation underscores the fast rate at which technical businesses are scaling their operations to dominate the quantum hardware and semiconductor sectors. The competitive environment that Chattanooga’s new workers will be entering is underlined by such incidents.

Technological Context: Beyond Broadband

The company, which is often recognized as one of the leading Municipal Electric Utilities and Internet Access providers in the US, is undergoing a major transformation with its entry into quantum computing. The entry into Quantum Information Science signals a change towards a more varied technology portfolio that includes:

Applied Quantum Mechanics: Going beyond theory to create useful instruments for the energy and utility sectors. Advanced Computer Hardware: Managing and maintaining sophisticated systems like the IonQ Forte Enterprise. Electricity Economics: Investigating the potential for quantum computation to maximize resilience and energy distribution. As the quantum computing fellowship continues, it is planned to disclose unique insights into Scientific Problems that were previously deemed impenetrable by classical computer rules.

[govindhtech]

LOQC Linear Optical Quantum Computing With Photonic Qubits

Optomechanics breakthroughs, high-efficiency photon sources, and industrial investment are scaling linear optical quantum computing (LOQC). Other quantum systems require cryogenic freezing, however LOQC uses fiber-optic communication infrastructure at normal temperature.

Quantum Light Revolution: Scalable Computing Reborn

Linear Optical Quantum Computing (LOQC) is advancing quantum domination. Researchers and businesses are using light's unique properties to overcome environmental noise and cooling needs that have slowed superconducting and ion-trap systems.

How LOQC Works: Light Computing

A LOQC system encodes qubits into photon polarization, spatial mode, or temporal bin. Photons rarely interact, therefore they have good coherence and are less susceptible to environmental interference.

Deterministic entangling gates are difficult to implement without interaction. LOQC addresses this via measurement-based quantum computing. This processing method uses photon-counting measurements on probabilistically created "resource states," small entangled photon groups.

Breakthrough: Optomechanics and Fault Tolerance One of the biggest industry advances is optomechanics, which uses light and sound to tolerate faults. Redundantly encoding information allows a system to continue computing accurately even if little errors occur.

With Phonons

Recently, phonons (particles of vibration) were found to be ideal for storing quantum information due to their long lifespan and stability.

Acoustic Memory: Researchers propose converting phonons into photons “on demand” to prepare quantum states.

Higher Efficiency: Traditional “read-write” memories require two conversions (light to memory and back), reducing efficiency. Only one conversion is needed with the new “emissive-type” optomechanical technology, improving system efficiency.

Experimental Simplicity: Optomechanical resonators do not need ultra-high vacuums or complex magnetic and microwave control fields like cold-atom systems.

Tech Milestones and Efficiency Barrier Loss-tolerance prevented LOQC scaling for years. Too many photons lost during detection or transmission destroy quantum information.

Industrial Landscape 2025–2030

The commercial sector is investing heavily in photonic platforms as the best path to million-qubit computers.

In late 2025, Japanese telecom company NTT partnered with OptQC Corp to build a reliable optical quantum computer. NTT hopes to reach one million qubits by 2030 using its optical amplification and multiplexing expertise.

Photonic Inc. received CAD $180 million in early 2026 to improve distributed photonic computing. Startups like Quantum Source Labs have raised tens of millions for hybrid photonic-atomic devices.

European Initiatives: The €50 million P4Q pilot aims to standardize photonic circuit production to minimize industrial bottlenecks, while EuroHPC provides cloud access to the 12-qubit “Lucy” photonic processor.

Persistent Universal Computing Challenges

Even though LOQC has advanced, researchers are still trying to overcome its core obstacles:

Gate Probability: Many LOQC operations have a low success rate. Complex multiplexing and “ancilla” resources are needed to maintain circuit performance.

Thermal Management: Intense lasers heat optomechanical components. Engineers use “thermal anchoring” and specialized materials to restrict optical absorption and maintain stability.

Indistinguishability: Quantum interference requires identical photons. The output optical frequencies of hundreds of devices must match, yet acoustic frequencies can vary.

Hardware Loss: Scale-scale photon loss requires sophisticated error-correction approaches even with high-efficiency sources.

Future Outlook: Beyond Lab

A hybrid quantum-classical model is coming to LOQC. Photonic quantum processors boost machine learning, AI, and optimization alongside CPUs in this arrangement.

Photon-based LOQC has obvious implications for quantum cybersecurity, providing unique methods to secure quantum key distribution communications. With the global photonic quantum market expected to reach $1.1 billion by 2030, optomechanical research and industrial scaling suggest that light will fuel the “next revolution in computing”.

[govindhtech]

Fusion-Based Quantum Computation With Photonic Quantum

Long known that a scalable, fault-tolerant quantum computer requires millions of physical qubits and advanced error correction. Photonic quantum computing, which encodes quantum information using photons (light particles), is one of the most promising pathways and is making remarkable progress, notably with Fusion-Based Quantum Computation. Studies and technological advances bring error-corrected quantum processing with light closer than ever.

Knowing Fusion-Based Quantum Computation

FBQC, a quantum computation method, uses photons and “fusion” processes to build complicated entangled states for quantum algorithms. FBQC accumulates entangled resources using ‘fusion’ measurements, unlike other quantum computing models that use gate-by-gate applications. This method is ideal for photonic systems since photons' low noise has been crucial to the early demonstrations of superposition, entanglement, and logic gates. Large-scale photonic quantum computing has been problematic because it requires several components that outperform the most modern conventional integrated photonics, such as highly efficient single-photon detectors and complicated integrated systems.

A Photonic Platform for FBQC

The establishment of a scalable photon-based quantum computing platform using silicon photonics manufacturing is a huge accomplishment. With a fully integrated 300-mm silicon photonics process flow, this platform designed with GlobalFoundries ensures scalability and performance similar to high-volume commercial setups.

Important components and their performance are crucial for FBQC:

High-Fidelity Heralded Single-Photon Sources (HSPS): These sources are essential to FBQC and use spontaneous four-wave mixing (SFWM) to generate a photon's pair probabilistically. The platform achieved coincidence-to-accidentals ratios of up to 3,000 for single-photon production on-chip. The initial sources have a spectral purity of 99.5% ± 0.1% without filtration.

Photonic quantum computing uses high-efficiency photon detection to indicate quantum state formation. Niobium nitride (NbN) layers enable high-performance superconducting nanowire single-photon detectors (SNSPDs) with 93.4% median on-chip detection efficiency.

With an average SPAM fidelity of 99.98% ± 0.01%, the platform proficiently prepares and measures single, path-encoded qubits. Great fidelity is needed for quantum processes to be accurate.

Quantum modules must be networked to scale beyond a single chip. With a point-to-point qubit network, the platform achieved a Pauli transfer matrix fidelity of 99.72% ± 0.04% for qubits delivered over 42 meters of optical fibre. Telecommunications-wavelength photonic qubits can transmit without quantum translation.

High-Visibility HOM measures photon interference between two on-chip sources with 99.50% ± 0.25% visibility, setting a new standard for photonic quantum computation.

High-Fidelity Two-Qubit Fusion: FBQC's eponymous operation, Bell fusion, projects onto two-qubit Bell states. The platform demonstrated a fidelity of 99.22% ± 0.12% with the ideal Bell state.

Fault-Tolerant, Low-Overhead FBQC

The baseline technology performs well, but significant improvements are needed to enable “useful” fault-tolerant quantum computing, especially in component loss and deterministic operations. This is where blocklet concatenation and other advanced error correction methods help.

PsiQuantum's Daniel Litinski and colleagues have released research on FBQC-specific “blocklet concatenation” methods. These protocols aim for fault-tolerant operation with reduced overheads than surface codes.

Key elements of this improved error correction include:

Blocklets: This developing technology encodes a single logical qubit, the fundamental, protected unit of quantum information, into multiple physical qubits to reduce error risk and enable modular and scalable architectures.

Code Distance: This crucial metric reveals how few physical qubit errors are needed to cause a wrong logical state. The research conjecture is that the code distance scales favourably with the product of the inner and product code distances raised to L-2. The blocklet code design has L layers.

Numerical simulations indicate subthreshold scaling, supporting the hypothesised link between minimum-weight errors and code distance. This is important because it shows that the code can rectify errors even when the physical error rate is below a threshold, which is required for actual quantum computing. Using 8, 10, and 12-qubit resource states, researchers developed protocol families with 13.8%, 19.1%, and 11.5% erasure thresholds. Erasure threshold, the greatest physical error rate at which these codes can consistently retrieve quantum information, illustrates their practicality.

Footprint Scaling: The resource cost per logical qubit, or "footprint," scales favourably. Unlike surface codes, which require many physical qubits to encode a single logical qubit, this may save resources.

The work proposes applying similar protocols to other quantum computing platforms in addition to photonic hardware, including logical operations, decoding, and implementation.

Technological Advances for FBQC Systems

The report lists several next-generation elements and technologies needed for fault-tolerant quantum computing:

SiN Waveguides with Low Loss: SiN waveguides have a lower refractive index contrast and greater confinement and manufacturing sensitivity than silicon-on-insulator waveguides. Their multimode waveguide losses are as low as 0.5 ± 0.3 dB m⁻¹.

Cascaded Resonator Sources, also known as fabrication-tolerant photon sources, address cryogenic thermal dissipation and pump power issues. A 24-resonator device achieved >99% two-source indistinguishability over a ±400-pm resonance shift, with 99.35% purity and remarkable manufacturing stability.

Super-efficient photon-number-resolving detectors Unlike single-photon detectors, PNRDs can distinguish low photon numbers, allowing FBQC to exclude higher-order photon number states and detect unwanted events. PNRDs with waveguides can resolve four photons and have 98.9% median on-chip detection efficiency with five unit cells.

Low-Loss Fibre-to-Chip Coupling: Practical fibre networking requires reducing loss when coupling optical fibres to photonic chips. New edge coupler designs for high-numerical aperture fibre exhibit coupling losses of 52 ± 12 mdB.

Fast electro-optic switches (BTO) are needed to overcome fusion gate and spontaneous source non-determinism. Barium Titanate (BTO) as an electro-optic phase shifter with high Pockels values allows the creation of vast, low-loss switching networks. The half-wave loss-voltage product is 0.33 ± 0.02 dB.V.

The Way Forward

FBQC approaches may tolerate 1% per-qubit fusion network faults and 10% optical loss between photon generation and detection. The shown feature-complete collection of optical components with optical losses of several percent or less and fully integrated circuits with sub-percent error levels is a big step.

The adaptable and industrially producible quantum photonic platform offers a scalable path to fault-tolerant quantum computers, but material and component losses, filter performance, and detector efficiency must improve. FBQC, underpinned by a robust stack of photonic technologies, is dramatically transforming quantum computation and opening the door to solve previously unsolvable problems in many industries.

[govindhtech]

PsiQuantum Unveils Loss-Tolerant Photonic Quantum Computing

Loss-Tolerant Photonic Quantum Computing

Loss-Tolerant Photonic quantum computing Road Map by PsiQuantum Research

A recent PsiQuantum study found a promising blueprint for creating quantum computers that can overcome photon loss, a fundamental challenge for photonic qubits. The arXiv article evaluates many fusion-based quantum computing (FBQC) architectures and shows that adaptive measurements and well constructed resource states may enable fault-tolerant photonic systems.

Despite its room-temperature functioning and fibre optic transmission, photonic quantum computing has been hampered by photon fragility. In a photonic system, one photon symbolises each qubit, hence destroying it destroys its quantum information. Because of this vulnerability, fault tolerance is difficult.

A PsiQuantum study, “PsiQuantum Study Maps Path to Loss-Tolerant Photonic Quantum Computing,” examines FBQC, an architecture that uses entangling operations, or fusions, between small, pre-prepared resource states. These materials are then mixed to form quantum computation architectures. By testing alternative methods in real-world circumstances, the research seeks to find the best hardware cost-mistake tolerance trade-off.

The research parameter Loss Per Photon Threshold (LPPT) quantifies the maximum photon loss a system may tolerate before errors become unmanageable. LPPT is less than 1% for simple “boosted” fusion networks without adaptivity or encoding. The PsiQuantum team advances by making key breakthroughs.

One strategy is encoding, which organises quantum information across photons. Using a 6-ring network resource state with a {2,2} Shor code, researchers achieved an LPPT of 2.7%. Measurement adaptivity, which dynamically alters upcoming operations based on past measurements, boosts robustness. Adding adaptivity to a four-qubit code raised the LPPT to 5.7%.

The most advanced systems, especially those using “exposure-based adaptivity,” showed much greater benefits. This advanced technique carefully selects and orders measurements to prioritise system components prone to error buildup. LPPT with 168 qubit resource state reached 17.4%. The “loopy diamond” network, an updated design with 224 qubits and {7,4} encoding, obtained 18.8% loss tolerance.

In addition to encoding and flexibility, geometry is crucial to system robustness. The team examined 4-star, 6-ring, and 8-loopy-diamond network topologies, which affect loss tolerance, resource creation ease, and photon entanglement and measurement. Global adaptivity affects the entire fusion network based on aggregate outcomes, while local adaptivity modifies fusions within small photon clusters.

The study stresses that greater loss thresholds often need larger and more complicated resource states, which can be costly. Creating these states from 3GHZ states, which are three-photon building blocks, needs a lot of resources. A 24-qubit 6-ring state requires more than 1,500 3GHZ states, whereas a 224-qubit loopy diamond network takes over 52,000. Current technology cannot set up and perform quantum calculations due to resource requirements.

The work maps the “tradeoff space” by comparing the performance advantage of each extra photon against its prohibitive cost, rather than just striving for the highest thresholds. The research found that a 32-qubit loopy diamond resource state is cheaper and more loss-tolerant than a 24-qubit 6-ring. The work reveals that adaptive systems might theoretically achieve a 50% LPPT, but this would require impossibly enormous resource states. It plots LPPT against resource size for dozens of ways.

The best small-to-medium systems achieve 15% to 19% LPPT, depending on adaptability and geometry. These results help find design "sweet spots" that balance hardware complexity and loss tolerance. Short-term implementations should focus on smaller resource states and clever adaptability, according to the authors.

The paper provides cost models to estimate the number of elementary operations needed to build each resource state. Even with perfect fusion and little photon loss during assembly, resource costs skyrocket with encoding size.

This paper shows a path to fault-tolerant photonic quantum computing, which is still far off. Using adaptive measurements, error-correcting codes, and optimised network architecture sparingly can reduce photon loss. These findings are essential for photonic qubit companies like PsiQuantum, which prefers them to trapped ions or superconducting circuits. The PsiQuantum team's standardised benchmarking approach, which defines the challenge in terms of LPPT and resource cost, helps system builders choose ideal configurations.

The study confesses to simple cost assumptions like perfect switching and negligible assembly losses that may not apply in practice. Instead of considering decoherence, gate defects, and external noise, it focusses on theoretical error thresholds. As resource states grow, low-latency feedback loops, quick switching networks, and classical control systems will be needed to sustain measurement adaptivity.

Experimental testing, integration into full-stack designs, and cost model refinement using photonic device data are planned for these adaptive approaches. The study also suggests that partial photon loss-resistant “scrap” information quantum states may benefit non-adaptive systems.