StudentsEducators

Schrödinger’s Cat Paradox

Schrödinger’s Cat is a thought experiment proposed by physicist Erwin Schrödinger in 1935 to illustrate the concept of superposition in quantum mechanics. In this scenario, a cat is placed in a sealed box with a radioactive atom, a Geiger counter, and a vial of poison. If the atom decays, the Geiger counter triggers the release of the poison, resulting in the cat's death. According to quantum mechanics, until the box is opened and observed, the cat is considered to be in a superposition state—simultaneously alive and dead. This paradox highlights the strangeness of quantum mechanics, particularly the role of the observer in determining the state of a system, and raises questions about the nature of reality and measurement in the quantum realm.

Other related terms

contact us

Let's get started

Start your personalized study experience with acemate today. Sign up for free and find summaries and mock exams for your university.

logoTurn your courses into an interactive learning experience.
Antong Yin

Antong Yin

Co-Founder & CEO

Jan Tiegges

Jan Tiegges

Co-Founder & CTO

Paul Herman

Paul Herman

Co-Founder & CPO

© 2025 acemate UG (haftungsbeschränkt)  |   Terms and Conditions  |   Privacy Policy  |   Imprint  |   Careers   |  
iconlogo
Log in

H-Bridge Pulse Width Modulation

H-Bridge Pulse Width Modulation (PWM) is a technique used to control the speed and direction of DC motors. An H-Bridge is an electrical circuit that allows a voltage to be applied across a load in either direction, which makes it ideal for motor control. By adjusting the duty cycle of the PWM signal, which is the proportion of time the signal is high versus low within a given period, the effective voltage and current delivered to the motor can be controlled.

This can be mathematically represented as:

Duty Cycle=tonton+toff\text{Duty Cycle} = \frac{t_{\text{on}}}{t_{\text{on}} + t_{\text{off}}}Duty Cycle=ton​+toff​ton​​

where tont_{\text{on}}ton​ is the time the signal is high and tofft_{\text{off}}toff​ is the time the signal is low. A higher duty cycle means more power is supplied to the motor, resulting in increased speed. Additionally, by reversing the polarity of the output from the H-Bridge, the direction of the motor can easily be changed, allowing for versatile control of motion in various applications.

Noether Charge

The Noether Charge is a fundamental concept in theoretical physics that arises from Noether's theorem, which links symmetries and conservation laws. Specifically, for every continuous symmetry of the action of a physical system, there is a corresponding conserved quantity. This conserved quantity is referred to as the Noether Charge. For instance, if a system exhibits time translation symmetry, the associated Noether Charge is the energy of the system, which remains constant over time. Mathematically, if a symmetry transformation can be expressed as a change in the fields of the system, the Noether Charge QQQ can be computed from the Lagrangian density L\mathcal{L}L using the formula:

Q=∫d3x ∂L∂(∂0ϕ)δϕQ = \int d^3x \, \frac{\partial \mathcal{L}}{\partial (\partial_0 \phi)} \delta \phiQ=∫d3x∂(∂0​ϕ)∂L​δϕ

where ϕ\phiϕ represents the fields of the system and δϕ\delta \phiδϕ denotes the variation due to the symmetry transformation. The importance of Noether Charges lies in their role in understanding the conservation laws that govern physical systems, thereby providing profound insights into the nature of fundamental interactions.

Poincaré Map

A Poincaré Map is a powerful tool in the study of dynamical systems, particularly in the analysis of periodic or chaotic behavior. It serves as a way to reduce the complexity of a continuous dynamical system by mapping its trajectories onto a lower-dimensional space. Specifically, a Poincaré Map takes points from the trajectory of a system that intersects a certain lower-dimensional subspace (known as a Poincaré section) and plots these intersections in a new coordinate system.

This mapping can reveal the underlying structure of the system, such as fixed points, periodic orbits, and bifurcations. Mathematically, if we have a dynamical system described by a differential equation, the Poincaré Map PPP can be defined as:

P:Rn→RnP: \mathbb{R}^n \to \mathbb{R}^nP:Rn→Rn

where PPP takes a point xxx in the state space and returns the next intersection with the Poincaré section. By iterating this map, one can generate a discrete representation of the system, making it easier to analyze stability and long-term behavior.

Hausdorff Dimension

The Hausdorff dimension is a concept in mathematics that generalizes the notion of dimensionality beyond integers, allowing for the measurement of more complex and fragmented objects. It is defined using a method that involves covering the set in question with a collection of sets (often balls) and examining how the number of these sets increases as their size decreases. Specifically, for a given set SSS, the ddd-dimensional Hausdorff measure Hd(S)\mathcal{H}^d(S)Hd(S) is calculated, and the Hausdorff dimension is the infimum of the dimensions ddd for which this measure is zero, formally expressed as:

dimH(S)=inf⁡{d≥0:Hd(S)=0}\text{dim}_H(S) = \inf \{ d \geq 0 : \mathcal{H}^d(S) = 0 \}dimH​(S)=inf{d≥0:Hd(S)=0}

This dimension can take non-integer values, making it particularly useful for describing the complexity of fractals and other irregular shapes. For example, the Hausdorff dimension of a smooth curve is 1, while that of a filled-in fractal can be 1.5 or 2, reflecting its intricate structure. In summary, the Hausdorff dimension provides a powerful tool for understanding and classifying the geometric properties of sets in a rigorous mathematical framework.

Moral Hazard

Moral Hazard refers to a situation where one party engages in risky behavior or fails to act in the best interest of another party due to a lack of accountability or the presence of a safety net. This often occurs in financial markets, insurance, and corporate settings, where individuals or organizations may take excessive risks because they do not bear the full consequences of their actions. For example, if a bank knows it will be bailed out by the government in the event of failure, it might engage in riskier lending practices, believing that losses will be covered. This leads to a misalignment of incentives, where the party at risk (e.g., the insurer or lender) cannot adequately monitor or control the actions of the party they are protecting (e.g., the insured or borrower). Consequently, the potential for excessive risk-taking can undermine the stability of the entire system, leading to significant economic repercussions.

Brayton Cycle

The Brayton Cycle, also known as the gas turbine cycle, is a thermodynamic cycle that describes the operation of a gas turbine engine. It consists of four main processes: adiabatic compression, constant-pressure heat addition, adiabatic expansion, and constant-pressure heat rejection. In the first process, air is compressed, increasing its pressure and temperature. The compressed air then undergoes heat addition at constant pressure, usually through combustion with fuel, resulting in a high-energy exhaust gas. This gas expands through a turbine, performing work and generating power, before being cooled at constant pressure, completing the cycle. Mathematically, the efficiency of the Brayton Cycle can be expressed as:

η=1−T1T2\eta = 1 - \frac{T_1}{T_2}η=1−T2​T1​​

where T1T_1T1​ is the inlet temperature and T2T_2T2​ is the maximum temperature in the cycle. This cycle is widely used in jet engines and power generation due to its high efficiency and power-to-weight ratio.