Tom Wong
@thomaswong.net
Physics professor at Creighton University. Quantum computing researcher. Views my own.
Yesterday in #PHY131 #QuantumForEveryone: Lasers are one of the most important inventions of the 20th century. It uses stimulated emission to create more and more coherent photons that are released as a collimated monochromatic beam.
September 16, 2026 at 9:58 PM
Yesterday in #PHY131 #QuantumForEveryone: Lasers are one of the most important inventions of the 20th century. It uses stimulated emission to create more and more coherent photons that are released as a collimated monochromatic beam.
Today in #PHY531 #QuantumMechanics: The first midterm, covering the statistical nature of the wave function through the particle in a box. Here's the first question:
September 14, 2026 at 7:26 PM
Today in #PHY531 #QuantumMechanics: The first midterm, covering the statistical nature of the wave function through the particle in a box. Here's the first question:
The Fields Medal is often described as the "Nobel Prize of Mathematics." Twenty-five Fields Medalists have signed an joint statement about "A Severe Misalignment of AI in Mathematics." mathandai.org
September 12, 2026 at 4:28 AM
The Fields Medal is often described as the "Nobel Prize of Mathematics." Twenty-five Fields Medalists have signed an joint statement about "A Severe Misalignment of AI in Mathematics." mathandai.org
Yesterday in #PHY131 #QuantumForEveryone: Each atom's spectra is like a barcode or fingerprint that uniquely identifies the element. They are why neon signs and fireworks are different colors. In spectroscopy, an object's spectrum determines what it is made of and how it moves.
September 11, 2026 at 7:00 PM
Yesterday in #PHY131 #QuantumForEveryone: Each atom's spectra is like a barcode or fingerprint that uniquely identifies the element. They are why neon signs and fireworks are different colors. In spectroscopy, an object's spectrum determines what it is made of and how it moves.
My *third* paper with undergraduate student Jonas Duda is out! In "Faster Computation with the Generalized Laplacian Quantum Walk," we give a quantum walk that outperforms typical quantum walks at a search problem and solves it optimally. arxiv.org/abs/2609.10429
September 10, 2026 at 2:26 AM
My *third* paper with undergraduate student Jonas Duda is out! In "Faster Computation with the Generalized Laplacian Quantum Walk," we give a quantum walk that outperforms typical quantum walks at a search problem and solves it optimally. arxiv.org/abs/2609.10429
Today in #PHY531 #QuantumMechanics: A particle trapped in a box with initial wave function equal to an upside-down parabola has a probably density that evolves as shown in the animation.
September 9, 2026 at 7:57 PM
Today in #PHY531 #QuantumMechanics: A particle trapped in a box with initial wave function equal to an upside-down parabola has a probably density that evolves as shown in the animation.
Today in #PHY131 #QuantumForEveryone: We made spectrometers and saw that only certain colors are emitted from each element. The Bohr model of the atom explains this by restricting electrons to discrete shells. Electrons absorb and emit photons to jump up and fall down.
September 9, 2026 at 3:40 AM
Today in #PHY131 #QuantumForEveryone: We made spectrometers and saw that only certain colors are emitted from each element. The Bohr model of the atom explains this by restricting electrons to discrete shells. Electrons absorb and emit photons to jump up and fall down.
Today in #PHY531 #QuantumMechanics: Say a particle in a box has an initial wave function that's an upside-down parabola. Expressing it as a linear combination of the eigenstates of the Hamiltonian, which are sines, is finding its Fourier series.
September 5, 2026 at 4:31 AM
Today in #PHY531 #QuantumMechanics: Say a particle in a box has an initial wave function that's an upside-down parabola. Expressing it as a linear combination of the eigenstates of the Hamiltonian, which are sines, is finding its Fourier series.
One of my students drew a picture on their homework. #PHY531 #QuantumMechanics
September 4, 2026 at 7:44 PM
One of my students drew a picture on their homework. #PHY531 #QuantumMechanics
New paper with postdoc/mathematician Yujia Shi! By adjusting the strength of a nonlinear quantum walk, we can selectively trap and release a particle, which allows timing in state transfer or use as a quantum memory. doi.org/10.1088/1402...
September 4, 2026 at 1:55 PM
New paper with postdoc/mathematician Yujia Shi! By adjusting the strength of a nonlinear quantum walk, we can selectively trap and release a particle, which allows timing in state transfer or use as a quantum memory. doi.org/10.1088/1402...
Today in #PHY131 #QuantumForEveryone: Einstein explained the photoelectric effect, where light ejects electrons from a metal, by proposing that Planck's quantized energies correspond to particles, now called photons. The effect is the basis for image intensification night vision.
September 3, 2026 at 9:51 PM
Today in #PHY131 #QuantumForEveryone: Einstein explained the photoelectric effect, where light ejects electrons from a metal, by proposing that Planck's quantized energies correspond to particles, now called photons. The effect is the basis for image intensification night vision.
Yesterday in #PHY531 #QuantumMechanics: The stationary states of a particle in a box are sine functions, which go to zero at the ends of the box. Their various wavelengths give rise to different energies, which are spaced quadratically apart.
September 3, 2026 at 4:14 PM
Yesterday in #PHY531 #QuantumMechanics: The stationary states of a particle in a box are sine functions, which go to zero at the ends of the box. Their various wavelengths give rise to different energies, which are spaced quadratically apart.
Today in #PHY201 #GenPhys1: Ignoring air resistance, objects near the surface of the earth feel an acceleration due to gravity of -9.8 m/s^2, regardless of the mass of the object. This is constant acceleration, so we can use the kinematic equations for such "free fall" problems.
September 2, 2026 at 4:43 PM
Today in #PHY131 #QuantumForEveryone: Planck explained blackbody radiation by proposing a quantum of energy = hf.
Applications:
(1) Blackbody radiation explains why people emit infrared light, which thermal imaging picks up.
(2) Planck's constant defines the kilogram.
Applications:
(1) Blackbody radiation explains why people emit infrared light, which thermal imaging picks up.
(2) Planck's constant defines the kilogram.
September 1, 2026 at 5:00 PM
Today in #PHY131 #QuantumForEveryone: Planck explained blackbody radiation by proposing a quantum of energy = hf.
Applications:
(1) Blackbody radiation explains why people emit infrared light, which thermal imaging picks up.
(2) Planck's constant defines the kilogram.
Applications:
(1) Blackbody radiation explains why people emit infrared light, which thermal imaging picks up.
(2) Planck's constant defines the kilogram.
Today in #PHY531 #QuantumMechanics: Schrödinger's equation is a PDE. If the potential is time independent, it separates into two ODEs. One yields a complex exponential in time. The other is the time-independent Schrödinger equation, an eigenvalue relation for the Hamiltonian.
August 31, 2026 at 9:26 PM
Today in #PHY531 #QuantumMechanics: Schrödinger's equation is a PDE. If the potential is time independent, it separates into two ODEs. One yields a complex exponential in time. The other is the time-independent Schrödinger equation, an eigenvalue relation for the Hamiltonian.
Today in #PHY531 #QuantumMechanics: The expected value of a quantity Q(x,p) is found by replacing p with its operator, sandwiching Q between Ψ* and Ψ, and integrating. The spread of position and momentum measurements of identically prepared systems satisfy Heisenberg's uncertainty principle.
August 28, 2026 at 9:10 PM
Today in #PHY531 #QuantumMechanics: The expected value of a quantity Q(x,p) is found by replacing p with its operator, sandwiching Q between Ψ* and Ψ, and integrating. The spread of position and momentum measurements of identically prepared systems satisfy Heisenberg's uncertainty principle.
I've been using a refillable dry erase marker for #PHY531 #QuantumMechanics, which only last 1.75 lectures. I mentioned bringing a second marker, and a student said, "It's faster to switch to your secondary than refill your primary." That earned a laugh and a tweet.
August 28, 2026 at 6:51 PM
I've been using a refillable dry erase marker for #PHY531 #QuantumMechanics, which only last 1.75 lectures. I mentioned bringing a second marker, and a student said, "It's faster to switch to your secondary than refill your primary." That earned a laugh and a tweet.
Today in #PHY131 #QuantumForEveryone: Students shined lasers through two slits and saw bright and dark fringes, corresponding to constructive and destructive interference, so light is a wave. It's an electromagnetic wave, and different wavelengths have different names and uses.
August 27, 2026 at 7:45 PM
Today in #PHY131 #QuantumForEveryone: Students shined lasers through two slits and saw bright and dark fringes, corresponding to constructive and destructive interference, so light is a wave. It's an electromagnetic wave, and different wavelengths have different names and uses.
Yesterday in #PHY531 #QuantumMechanics: For a plane wave to satisfy the Einstein and de Broglie relations, energy and momentum are differential operators. The Hamiltonian equals the total energy, and we get Schrödinger's equation. A normalized wave function stays normalized.
August 27, 2026 at 6:12 PM
Yesterday in #PHY531 #QuantumMechanics: For a plane wave to satisfy the Einstein and de Broglie relations, energy and momentum are differential operators. The Hamiltonian equals the total energy, and we get Schrödinger's equation. A normalized wave function stays normalized.
Today in #PHY531 #QuantumMechanics: A review of probability, including measures of central tendency and spread. Variance is the average of the squared deviation from the mean, but it can be found from the average of the square minus the average squared.
August 24, 2026 at 8:23 PM
Today in #PHY531 #QuantumMechanics: A review of probability, including measures of central tendency and spread. Variance is the average of the squared deviation from the mean, but it can be found from the average of the square minus the average squared.
First day of #PHY531 #QuantumMechanics: Firing electrons through two slits, one at a time, results in a wave interference pattern, where the wave determines the likelihood of where the particle will be found. This is wave-particle duality. Relations include p = ħk and E = ħω.
August 19, 2026 at 7:43 PM
First day of #PHY531 #QuantumMechanics: Firing electrons through two slits, one at a time, results in a wave interference pattern, where the wave determines the likelihood of where the particle will be found. This is wave-particle duality. Relations include p = ħk and E = ħω.
Today in #PHY131 #QuantumForEveryone: 100% of my students had heard of "quantum" before, mostly from movies. A quantum is the smallest amount of something, so a sugar grain is a quantum of granulated sugar, and a water molecule is a quantum of water. Nearly everything has a quantum when you zoom in.
August 18, 2026 at 7:16 PM
Today in #PHY131 #QuantumForEveryone: 100% of my students had heard of "quantum" before, mostly from movies. A quantum is the smallest amount of something, so a sugar grain is a quantum of granulated sugar, and a water molecule is a quantum of water. Nearly everything has a quantum when you zoom in.