statistics

principal component analysis

A statistical method that extracts the main repeating patterns from data by reducing its dimensionality.
23 related articles

Description

Principal component analysis (PCA) is a statistical technique that reduces the dimensionality of a dataset while preserving as much of its variability as possible. It identifies the directions, called principal components, along which the data varies the most. The first principal component captures the largest variance, the second captures the next largest, and so on, with each component orthogonal to the previous ones. This transformation allows complex, high-dimensional data to be visualized and analyzed in a lower-dimensional space, often revealing hidden structure.

History

PCA was introduced by Karl Pearson in 1901 as a method for finding lines and planes that best fit a set of points. It was later formalized and popularized by Harold Hotelling in the 1930s, who applied it to psychometrics and economics.

How it works

PCA works by computing the covariance matrix of the data and then finding its eigenvectors and eigenvalues. The eigenvectors define the directions of maximum variance, and the eigenvalues give the amount of variance along each direction. By projecting the original data onto the top few eigenvectors, you obtain a compressed representation that retains most of the information. The process is equivalent to performing singular value decomposition on the data matrix.

In practice

PCA is widely used in image compression, facial recognition, genomics for analyzing gene expression data, and finance for risk management and portfolio optimization.

Fun fact

PCA is the mathematical foundation behind the 'eigenfaces' technique in facial recognition, where a face is represented as a combination of a few principal component images.

Related articles · 23

q-bio.MN2026-09-112 minarXiv:2609.90025
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q-bio.BM2026-08-191 minarXiv:2608.18604express
How Protein Engineers Learn from Mistakes
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Signal Processing2026-07-152 minarXiv:2607.13583express
An Orchestra of Imperfect Elements: How Manufacturing Irregularities Paradoxically Boost the Radio Signal
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Signal Processing2026-07-141 minarXiv:2607.12546express
How to Hear a Seizure in the Brain's Noise
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Gravitational Tango: How a Neural Network with Physical Intuition Heard the Rhythm of Black Holes
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Symphony of Scales: A Neural Network That Overheard Nature's Orchestra
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Materials2026-06-244 minarXiv:2606.25502
The Aroma of Matter: How a Quantum Perfumer Finds Alloys with Perfect Properties
Creating a material with desired properties is an art that long relied on intuition and luck. Nature gives no hints: dozens of elements in the periodic table, and the number of their combinations tends to infinity. Previously, materials scientists resembled alchemists, trying everything in a row, or relied on statistical models that lost power beyond the known.
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HEP Experiment2026-04-102 minarXiv:2604.09809express
Neural Network Learns to Spot Higgs Boson Decays
At the Large Hadron Collider, protons collide, and from the flash dozens of particles are born. Among them may be traces of rare processes — for example, the decay of a Standard Model Higgs boson into two W bosons. But these particles fly apart so quickly that their tracks merge into a single wide jet.
Quantum Physics2026-04-041 minarXiv:2604.03546express
How to Fit an Elephant in a Matchbox
Quantum annealing works like a smart way to find a path through a maze: instead of checking every dead end, it uses quantum effects to find the exit faster. But this maze has a quirk: the numbers that describe the walls and corridors must be roughly the same size.
Separating Signal from Noise in Particle Detectors
Particle detectors such as resistive plate chambers (RPCs) work like sensitive traps: when a charged particle flies through, it generates an electrical signal. But sometimes the chamber fires a false hit, as if an invisible hand pressed a doorbell. These spurious signals muddy the picture and make it harder to pinpoint the particle's path.
Materials2026-03-072 minarXiv:2603.07321express
How to Make Atoms Move Slowly
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Materials2026-02-281 minarXiv:2603.00740express
A Transparent Crystal Keeps an Eye on Your Pulse
A fingernail-sized piece of ceramic is squeezed in a vise, and its internal structure rearranges like clay under your fingers. Inside, orderly rows of tiny domains line up where they were once randomly oriented. After this 'massage,' the crystal lets light through almost like glass and, at the same time, generates a strong electric charge when bent or pressed.
q-bio.BM2026-01-311 minarXiv:2602.00660express
How Proteins Find Their Minimum
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q-bio.BM2026-01-311 minarXiv:2602.00782express
Proteins Without Stuttering
A protein language model is like a chef who learned from thousands of recipes and now invents new dishes. Sometimes he gets carried away and salts every dish because one good cookbook used a lot of salt. In proteins, such repetition isn't just ugly: identical stretches in the chain make the protein fragile, it can't fold into the right shape, and it doesn't work.
Optics2026-01-251 minarXiv:2601.17719express
Invisible Shield for a Perfect Light Absorber
An ordinary laser amplifies light into a bright beam. Run the process in reverse, and you get an anti-laser — a device that sucks in light without a trace. But such a machine is finicky: even a slight disorder can ruin the absorption. Physicists have found a way to make the anti-laser invulnerable.
Quantum Physics2026-01-101 minarXiv:2601.06524express
How to Make Quantum Computers More Accurate Without Extra Cost
A quantum computer is like an orchestra, where each qubit is a musician and the control signals are the conductor. If the conductor waves the baton imprecisely, the musicians fall out of sync. In a real device, signals pass through power amplifiers, like loudspeakers that add noise and distortion.
stat.ME2025-06-022 minarXiv:2506.01658
Compressing an Ocean into a Few Hundred Numbers: How a New Model Predicts El Niño
Climate scientists have long debated where exactly the El Niño "pool" is located: the region in the equatorial Pacific that first responds to an impending weather shift. The debate isn't due to a lack of data. The ocean is measured along longitude, latitude, and depth, and each slice contains thousands of numbers. The problem is that there are too many numbers to see the pattern directly.
Climate as an Interpreter: Hearing the Topic Shift, Not the Volume
An interpreter at a negotiation hears not only the volume of the voice but also the shift in topic. Climatologists have long listened only to volume: the average temperature. If it rises, the planet is warming. But behind the average hide events that matter more than the trend: heat waves, cold snaps, sudden changes.
Climate Teleconnections with a Time Lag
In 1960, a meteorologist at a station in Peru records water temperature, while a farmer in India watches the sky waiting for the monsoon. There is no direct link between these two events, but months later one will echo in the other.
eess.SY2020-04-233 minarXiv:2004.11411
How to Hear the Ocean's Voices
Earth's climate resembles a choir, where each member sings their own part at their own pitch. Some voices hold low notes, like multi-year ocean temperature oscillations, while others produce rapid trills, like short atmospheric waves. The conductor needs to hear each one, but the voices overlap and the notes blend into a mush.
stat.ME2016-05-022 minarXiv:1605.00346
Where Ice Breaks: Finding Change Points in a Random Flow
The ice cover of a river looks solid, but beneath it lie cracks that alter the flow. So it is with a time series: behind the smooth surface of numbers hide moments when the rules of the game change. These moments are called change points, and finding them is like tapping the ice to locate weak spots.