atomic clocks - 2025 ACF Winter

Question

The fountain type of these devices are more accurate due to longer observation times. For 10 points each:

[10m] Name these devices, examples of which include the new NIST-F4. These precision devices rely on electronic transitions in laser-cooled atoms, usually cesium.

ANSWER: atomic clocks [accept cesium atomic fountain clocks; prompt on clocks]

[10h] The resonant frequency of cesium-133 used in atomic clocks comes from this type of transition. The interaction between electron angular momentum and nuclear angular momentum breaks energy level degeneracy and creates this transition type.

ANSWER: hyperfine transition [accept hyperfine structure; reject “fine structure”]

[10e] A new generation of more accurate atomic clocks are named for using frequencies in this range, compared to the microwave transitions of cesium. This region of the electromagnetic spectrum has wavelengths slightly longer than ultraviolet.

ANSWER: visible spectrum [or visible light; or optical spectrum; or optical light; accept optical clocks; accept optical atomic clocks]

<Editors, Physics>

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Summary


Canada	Main	Y	6	18.33	67%	100%	17%
Florida	Main	Y	13	15.38	54%	85%	15%
Midwest	Main	Y	8	10.00	38%	50%	13%
Northeast	Main	Y	5	16.00	100%	60%	0%
Pacific Northwest	Main	Y	10	16.00	80%	60%	20%
South Central	Main	Y	5	14.00	40%	100%	0%
Upper Mid-Atlantic	Main	Y	8	17.50	75%	63%	38%
Upstate NY	Main	Y	8	16.25	63%	88%	13%
2025 ACF Nationals	2025-08-09	Y	3	16.67	67%	67%	33%

Data


UCI	UCLA C	10	0	10	20
UCLA A	Claremont Pitzer	10	0	0	10
Claremont Scripps	UCLA B	10	0	10	20
UCLA D	UCSD What Hath God Wrought	10	0	10	20
USC	UCSB	10	0	0	10
UCSD Two Running Violet V Forms	UCSD Vices and Virtues	10	10	10	30
Carleton	McGill B	10	10	10	30
Toronto B	McGill A	10	0	10	20
McGill C	Queen's A	10	0	10	20
McMaster B	Guelph B	10	0	10	20
Ottawa	Toronto C	10	0	0	10
Queen's B	Western Ontario	10	0	0	10
Guelph A	Toronto A	10	0	10	20
Toronto D	McMaster A	10	10	10	30
Waterloo	Toronto E	10	0	0	10
Toronto Metropolitan	Toronto G	10	0	0	10
Toronto I	McMaster C	0	0	0	0
Toronto J	Toronto F	10	0	0	10
Toronto K	Toronto H	0	0	10	10
Virginia B	James Madison	0	10	0	10
Liberty A	North Carolina B	10	0	10	20
Liberty B	South Carolina A	0	0	0	0
Clemson A	Liberty C	10	0	10	20
North Carolina A	NC State	10	0	0	10
South Carolina B	Clemson B	0	0	0	0
Tusculum	Virginia Tech B	0	0	10	10
North Carolina C	Virginia Tech A	10	0	0	10
Columbia A	Rowan A	10	0	10	20
Columbia B	Lehigh A	10	0	10	20
Vassar A	Columbia C	0	0	10	10
Princeton A	Rutgers B	10	0	10	20
Rutgers C	Lehigh B	0	0	10	10
Chicago A	Kentucky	10	0	10	20
Chicago B	Notre Dame B	10	0	10	20
Illinois A	Michigan B	10	0	10	20
Indiana B	Notre Dame C	0	0	0	0
Notre Dame A	Louisville A	0	0	10	10
Chicago C	Louisville B	0	10	10	20
Michigan C	Purdue C	10	0	10	20
Illinois B	Michigan D	10	10	10	30
Notre Dame D	Purdue A	0	0	0	0
Iowa State	Macalester A	10	0	0	10
Minnesota B	St. Thomas	10	0	10	20
Carleton	Nebraska	10	0	0	10
Minnesota C	Wisconsin	10	0	0	10
Arizona State A	UCO	10	10	10	30
Tulsa	Arizona State B	10	0	10	20
Macalester B	Minnesota A	10	0	10	20
Ohio	Iowa	0	0	0	0
Northwestern B	McGill D	10	10	10	30
Texas B	Northwestern A	0	0	10	10
UTD A	Rose State	10	0	10	20
Alberta B	Texas A	10	10	10	30
UTD B	Northwestern C	0	0	0	0
Illinois C	Chicago D	10	0	10	20
Alabama B	Auburn B	10	0	10	20
Georgia Tech A	Auburn A	10	0	10	20
Bruin A	Georgia Tech C	10	0	0	10
Georgia Tech B	Georgia Tech D	0	10	10	20
Mississippi State A	Huntsville B	10	0	10	20
UAB A	Sewanee A	10	0	0	10
Vanderbilt B	Vanderbilt A	10	0	0	10
Alabama A	Huntsville A	10	0	10	20
Oxford B	Cambridge D	0	10	10	20
Southampton B	Sheffield A	10	0	10	20
Durham A	Warwick A	10	0	0	10