Technology and the built world

Phrack

Phrack, also known as Phrack Magazine, is a free electronic hacker magazine founded in 1985 by Taran King and Knight Lightning, the underground computing scene's longest-running journal of technical articles.

Phreaking

Phreaking, or phone phreaking, is the exploration and manipulation of telephone networks to make free calls, flourishing from the late 1950s until blue box techniques stopped working in the early 1990s.

Phugoid

The phugoid, or phugoid cycle, is a slow, weakly damped oscillation in an aircraft's altitude and airspeed, with the angle of attack staying nearly constant.

Phuket International Airport

Phuket International Airport, also called Phuket Airport, serves Phuket island in southern Thailand, about 32 km northwest of Phuket Town. It is Thailand's third busiest airport.

Phulbari Coal Mine

The Phulbari Coal Mine is a proposed open-pit coal and power project at Phulbari in north-west Bangladesh, developed by GCM Resources and halted since 2006 by mass protest.

Phylion Battery (星恒电源)

Phylion Battery (星恒电源) is a Chinese lithium battery manufacturer founded in December 2003 in Suzhou, known for manganese-based batteries for electric two-wheelers with over 33 million packs sold.

Physical artificial intelligence

Physical artificial intelligence, or physical AI, is artificial intelligence embedded in machines that sense, decide, and act in the physical world, including robots, autonomous vehicles, and drones.

Physical human-robot interaction control

Physical human-robot interaction control is the branch of robot control regulating forces exchanged when a robot contacts a person or environment, chiefly via impedance and admittance control.

Physical Intelligence Inc.

Physical Intelligence Inc., also known as Physical Intelligence, is a San Francisco AI startup founded in 2024 by researchers from Google DeepMind, Stanford, and UC Berkeley that builds foundation models controlling robots.

Physical layer

The physical layer, or OSI layer 1, is the first layer of network architecture, conveying bit streams between devices as electrical, radio, or optical signals.

Physical vapor deposition

Physical vapor deposition (PVD) is a family of vacuum coating processes that vaporize a solid source material and condense it as a thin film on a substrate.

Physical verification

Physical verification is the sign-off stage in chip design where DRC and LVS checks confirm an integrated circuit layout is manufacturable and matches the intended design.

Physical-layer authentication

Physical-layer authentication is a set of techniques for verifying a wireless transmitter's identity or message integrity using hardware fingerprints and channel properties rather than upper-layer cryptography alone.

Physical-layer key generation

Physical-layer key generation is a wireless security technique in which two devices derive a shared encryption key from random fading of the radio channel between them.

Physically based rendering

Physically based rendering (PBR) is a computer graphics approach in which materials and light obey physical laws, especially energy conservation, so shaded surfaces look correct under any lighting.

Physics of failure

Physics of failure, abbreviated PoF, is a reliability engineering approach that models the physical and chemical mechanisms, such as fatigue, wear, and corrosion, that cause products to fail.

Physics-guided deep learning

Physics-guided deep learning trains neural networks to respect physical laws, typically partial differential equations or conservation laws, by adding physics-based terms to the training objective.

Physics-guided machine learning

Physics-guided machine learning is a family of methods that train models under physical laws or simulation data, keeping predictions consistent with governing equations while fitting noisy, sparse observations.

Physics-guided neural network

A physics-guided neural network (PGNN) is a neural network trained partly with physical laws, introduced in 2017 by Arka Daw and colleagues for lake temperature prediction.

Physics-informed deep learning

Physics-informed deep learning trains neural networks to fit data while satisfying physical laws, usually partial differential equations, so models match observations and obey governing equations.

Physics-informed machine learning

Physics-informed machine learning (PIML) embeds physical laws such as partial differential equations into machine learning training, so predictions respect known physics while fitting sparse or noisy data.

Physics-IQ

Physics-IQ is a Google DeepMind benchmark, released in January 2025, that tests whether generative video models understand intuitive physics by predicting how real filmed scenarios continue.

Physik Instrumente

Physik Instrumente (PI) is a German manufacturer of precision positioning and motion-control technology, headquartered in Karlsruhe, founded in 1970 and known especially for piezoelectric nanopositioning systems and hexapods.

Phytium Technology

Phytium Technology (飞腾信息技术有限公司) is a Chinese CPU design company headquartered in Tianjin, founded in 2014 by China Electronics Corporation and Tianjin partners, that develops ARMv8-based processors and was added to the US Entity List in 2021.

Pi (Inflection)

Pi is a conversational AI chatbot built by Inflection AI and released in May 2023, designed as a kind, supportive companion; it reached a million daily users before its founding team joined Microsoft in 2024.

PI controller

A PI controller, or proportional-integral controller, is a two-term feedback controller that sums proportional and integral action, driving steady-state error to zero in process control.

Pi network (electronics)

A pi network is a three-element impedance-matching circuit, with two shunt reactive elements around one series element, that lets the designer set Q independently of the impedance ratio.

Pi-hole

Pi-hole is a free, open-source network-level ad blocker that works as a DNS sinkhole, blocking ads and trackers on all devices, typically installed on a Raspberry Pi.

Piab

Piab is a Swedish manufacturer of industrial vacuum automation components, including ejectors, suction cups, robotic grippers, and vacuum conveyors, headquartered in Danderyd, Sweden, and founded in 1951.