Quantum-enhanced measurements can surpass the standard quantum limit, which is a classical bound on measurement precision. Quantum mechanics, through the Heisenberg uncertainty principle, imposes fundamental limits on measurement accuracy. Conventional techniques, such as shot noise and standard quantum limits, are not as fundamental as Heisenberg limits and can be overcome using quantum strategies like squeezing and entanglement. Measurement accuracy is governed by quantum mechanics, especially at small scales, where it imposes intrinsic uncertainties on complementary observables. These limits include the Heisenberg uncertainty relation and quantum constraints on the speed of evolution, such as the Margolus-Levitin theorem. Quantum back action, where measurement outcomes influence the system, can be detrimental, but strategies like quantum non-demolition measurements can mitigate this. Techniques such as entanglement and squeezed states allow for enhanced precision in measurements, such as in interferometry, where the shot noise limit can be beaten. Quantum-enhanced parameter estimation, like in Ramsey interferometry, can achieve higher precision by using entangled states. Applications of quantum-enhanced measurements include quantum frequency standards, quantum lithography, quantum positioning, and quantum imaging. These techniques leverage quantum effects to improve measurement accuracy, often surpassing classical limits. The standard quantum limit is not fundamental but can be beaten using quantum strategies. Quantum technologies, such as entanglement and squeezing, are being developed to enhance precision in various fields. The ultimate limits to measurement precision are governed by quantum mechanics, including the Margolus-Levitin theorem and quantum geometric limits. These limits define the fundamental precision thresholds for measuring spacetime geometry. Quantum mechanics not only imposes limits on measurement accuracy but also provides strategies to surpass classical limits, enabling advancements in quantum technologies.Quantum-enhanced measurements can surpass the standard quantum limit, which is a classical bound on measurement precision. Quantum mechanics, through the Heisenberg uncertainty principle, imposes fundamental limits on measurement accuracy. Conventional techniques, such as shot noise and standard quantum limits, are not as fundamental as Heisenberg limits and can be overcome using quantum strategies like squeezing and entanglement. Measurement accuracy is governed by quantum mechanics, especially at small scales, where it imposes intrinsic uncertainties on complementary observables. These limits include the Heisenberg uncertainty relation and quantum constraints on the speed of evolution, such as the Margolus-Levitin theorem. Quantum back action, where measurement outcomes influence the system, can be detrimental, but strategies like quantum non-demolition measurements can mitigate this. Techniques such as entanglement and squeezed states allow for enhanced precision in measurements, such as in interferometry, where the shot noise limit can be beaten. Quantum-enhanced parameter estimation, like in Ramsey interferometry, can achieve higher precision by using entangled states. Applications of quantum-enhanced measurements include quantum frequency standards, quantum lithography, quantum positioning, and quantum imaging. These techniques leverage quantum effects to improve measurement accuracy, often surpassing classical limits. The standard quantum limit is not fundamental but can be beaten using quantum strategies. Quantum technologies, such as entanglement and squeezing, are being developed to enhance precision in various fields. The ultimate limits to measurement precision are governed by quantum mechanics, including the Margolus-Levitin theorem and quantum geometric limits. These limits define the fundamental precision thresholds for measuring spacetime geometry. Quantum mechanics not only imposes limits on measurement accuracy but also provides strategies to surpass classical limits, enabling advancements in quantum technologies.